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How to enter your firm's Companies House Presenter ID and Presenter Authentication in Tax Optimiser, and how to apply for them if you don't have them yet.

Renew your HMRC connection in two minutes, and sort out the "incorrect Government Gateway account" message.

A VAT return can't be changed once HMRC has accepted it. Correct the error on your next return, or report it to HMRC, depending on its size.

What belongs in CT600 box 205, how the Non Trade Income grid takes the income out of the trading profit and taxes it on its own line, and what each column does.

Paid the submission fee against the wrong year? Move the payment to another accounting period of the same company from the Billing page, as long as nothing has been submitted for it.

What working papers record in Tax Optimiser, how a firm switches them on, and what appears on screen once they are.

QuickBooks connection lapsed? Reconnect in a couple of minutes from the Trial Balance or the Organisation page, then sync again. Nothing you have done is lost.

Interest a company receives is a non-trading loan relationship credit, taxed in CT600 box 170 after netting against interest paid. When Tax Optimiser picks it up for you, when it does not, and how to fill in the Non Trade Credit grid.

Use the Trial Balance tab of a working paper to compare each balance with last year, tick it as confirmed, explain it in a note and attach the evidence.

Xero connection lapsed? Check the Xero card, reconnect in a couple of minutes, then sync again. Nothing you have done is lost. You can also disconnect Xero from the same card.

Answer the firm's checklist, move the file through its stages, keep track of every working paper in the firm and print the report.

Generate a Sodium API key, paste it into your firm settings, pick your practice, and sync your limited-company clients into Tax Optimiser in one click.

Build the firm's working paper checklist from a ready-made pack, then add, edit, reorder and mark questions as required.

Leave a review point against any balance, see at a glance what is still outstanding, and clear each one with a response.

What a Companies House presenter ID is, how to apply for one on GOV.UK, and where to enter it so you can file your own company's accounts.

What counts as dormant for Companies House, what dormant accounts contain, and how to file them with the Dormant Accounts Wizard.

What the notes to your statutory accounts are, how the Notes screen in Tax Optimiser works, and a guide to every note.

What every box on the CT600 Company Tax Return means, how Tax Optimiser fills it, and where the figure comes from - with an entry for each box on the 2026 form.

Entering the return's income pages: multiple employments, self-employment short and full pages, UK property, and interest and dividends — with the HMRC box references on every field.

Partnership shares, foreign income with FTCR, trust and estate income, capital gains, residence status and the SA101 pages — how each supplementary schedule is entered and calculated.

How Tax Optimiser builds the directors' loans table from your loans to participators, and what to add when a loan is interest-bearing, repaid or written off.

Show the future minimum payments under non-cancellable operating leases, analysed by when they fall due.

Show long-term creditors from your trial balance, the amount due after five years and any security given.

Enable the service, link Companies House, add your UTR and create your first accounting period.

Disclose capital expenditure the company has contracted for at the year end but not yet recorded.

Already filed your accounts at Companies House? How to file just the CT600, why HMRC needs the full accounts, and how to check they match the filing.

The live SA302-style calculation: the staged statement, the band-by-band breakdown, PAYE coding adjustments and the claim to reduce payments on account, warnings, and the downloadable SA302 PDF.

How to disclose loans to directors and guarantees given on their behalf in micro-entity accounts.

The automatic penalty for filing accounts late: the bands, the doubling rule, extensions and appeals.

How to disclose capital commitments, other financial commitments and contingent liabilities in micro-entity accounts.

Break down the creditors due within one year on the balance sheet, line by line from your trial balance.

Which dealings with directors, their families and their other companies need disclosing in small company accounts, and the templates that help you word it.

State the number, class and nominal value of the company's allotted shares, agreed to the trial balance.

The cost, depreciation and net book value table for property, plant, vehicles and equipment, built from the trial balance.

A table of the items charged or credited in arriving at operating profit, read from the trial balance.

Disclose significant things that happened after the year end but before the accounts were approved, such as a dividend declared after the year end.

Show the movement on provisions other than deferred tax, from opening to closing balance.

Say who controls the company — an individual, a parent company or nobody — using one of three templates.

A members' club or association files a CT600 but nothing at Companies House, and its members' income is not taxable. Here is the whole journey, from signing up to sending the return.

Work through the calculation sections - disallowables, adjustments, donations and non-trade income - and watch the payable figure update live.

When your accounts are due at Companies House, how the accounting reference date sets the deadline, and what happens when you change it.

Disclose possible liabilities, such as guarantees given or legal claims, that are not provided for in the accounts.

Follow a trading loss from the year it is made to the year it is used: boxes 780, 160 and 285, losses before and after April 2017, and pulling the balance into the next period.

How FRS 105 (micro-entity) and FRS 102 Section 1A (small company) accounts differ, and the size thresholds - including the higher limits from 6 April 2025 - that decide which one your company uses.

What Making Tax Digital for Income Tax is, the four-step setup on your dashboard, and the difference between demo mode and live mode.

Sign the accounts, clear the pre-flight checks, and file to HMRC and Companies House through the guided wizards.

Every set of accounts and every CT600 hangs off an accounting period. Here is how the system creates them for you automatically from Companies House, and how to add one by hand when you need to.

Import from Xero, QuickBooks or a spreadsheet, or key the trial balance by hand - then make sure it balances.

A company that has never traded but has a notice to file from HMRC files a nil CT600. How to mark the period dormant, check the nil computation and send the return with dormant accounts attached.

Which capital allowance goes in which CT600 box: AIA, full expensing, the main and special rate pools, structures and buildings, and the expenditure boxes 760 to 775.

Read the loss movement, record brought-forward and carried-back losses (pre- and post-2017), and let the carried-forward balance calculate itself.

Show the movement on a capital contribution reserve: opening balance, contributions received and amounts utilised.

Replace a set of accounts you've already filed: check the original went through, correct the figures, mark them as amended, fill in the revision detail Companies House requires, and re-file.

The Gateway login is firm-wide with a per-client override; the Presenter ID is firm-only for firm-managed clients. Here are the rules, the override, and the errors.

Filing a client's accounts as a firm: credits instead of per-period fees, the firm's presenter credentials, and the pre-flight checks before the wizard sends.

Disallow depreciation, record your asset additions, and claim the Annual Investment Allowance.

Why a line in the accounts can be a pound away from the trial balance, and when you need to act.

Analyse the deferred tax provision or asset into revaluations, tax losses and other timing differences.

How the 19% and 25% rates, marginal relief and associated companies work, with three worked examples and every CT600 box from 326 to 440.

Interest on borrowing that is not for the trade - shares, let property, investments - is a non-trading loan relationship debit. How to move it out of the trade with the Non Trade Debit grid, and how a non-trading deficit is relieved in boxes 795, 260 and 263.

Disclose the fair value of forward contracts, swaps and other derivatives, and describe what they are for.

Directors' loans, the section 455 charge (35.75% from April 2026) and the relief that cancels it - how to enter loans in Tax Optimiser and what every box on the CT600A means.

Boxes 3.99 to 3.115: assets, liabilities and the partners' accounts, with all three totals calculated and a built-in way to check the sheet balances.

The movement in long-term investments such as shares in a subsidiary, taken from your trial balance, plus the details small companies give about subsidiaries.

Analyse the current asset investments on your balance sheet between listed and unlisted holdings.

How a company with investment business deducts its management expenses and the capital allowances on its investment-business assets - the Management Expenses tab, excess carried forward, and CT600 boxes 245, 255, 850 and 733.

The 100% first-year allowance for new electric vans and other zero-emission goods vehicles - who could claim it, its end for companies on 31 March 2025, how to record the vehicle in Tax Optimiser, and what goes in CT600 boxes 723, 748 and 760.

How to add a note with your own heading and wording to FRS 105 or FRS 102 Section 1A accounts.

Disclose commitments and security not shown on the balance sheet that are not covered by the capital, lease or pension commitment notes.

When the company guarantees a director's personal borrowing, s413 requires it to be disclosed. Here is how to complete the table and the description.

How to choose, word and print the accounting policies note, with a guide to every policy in Tax Optimiser.

A breakdown of the tax charge into corporation tax and deferred tax, read from the trial balance.

The Economic Crime and Corporate Transparency Act changes to accounts filing, now due on 1 April 2028, and what to check before then.

How non-trading gains and losses on intangible fixed assets and capital allowances against non-trade income reach the CT600 - boxes 195, 265, 290 and 830 on the Intangibles & Other Reliefs section.

How a company is taxed on the sale of property, shares and other capital assets - recording disposals on the Chargeable Gains tab, using capital losses, and what goes in CT600 boxes 210, 215, 220 and 825.

Claiming and surrendering losses between group and consortium companies - how to complete the CT600C in Tax Optimiser and what every box from C1 to C225 means.

Explain a final salary scheme and show the assets, obligations and movement behind the pension balance.

Where the Partnership return (SA800) menu appears, what the returns list shows, what New Partnership Period prefills for you, and what a return costs to file.

How the average number of employees is disclosed in FRS 105 and FRS 102 Section 1A accounts, and where Tax Optimiser gets the figure.

Describe the company's pension arrangements, the cost for the year and any contributions outstanding.

A text note stating the dividends paid or proposed in the year, with templates for the usual wording.

The six-character code Companies House needs to accept your filing: where it comes from and where it goes in Tax Optimiser.

The ring fence trades supplementary page - when the CT600I is needed, how ring fence profits and the supplementary charge are taxed, how to complete it in Tax Optimiser and what each box from I1 to I160 means.

The insurance supplementary page - when the CT600D is needed, how to complete it in Tax Optimiser and what each box from D1 to D5 means.

Declaring the CT600 on a different day from the accounts approval? How to put the right date in box 980 without changing the approval date in the accounts.

The map of the journey: set your firm's filing credentials once, then create each client and file accounts and Corporation Tax through the two wizards.

The cross-border royalties supplementary page - when the CT600H is needed, how to complete it in Tax Optimiser and what every box from H1 to H5H means.

How a company gets credit for foreign tax on its overseas income - adding sources on the Double Taxation Relief tab, how the credit is limited to the UK tax on each source, and what goes in CT600 boxes 450, 470 and 475.

Prepare and file SA800 Partnership Tax Returns for LLP and partnership clients: a six-step wizard, self-calculating boxes, the official form as a PDF, and direct HMRC filing. In closed beta with accountancy firms and not yet open to the public.

Four ways to add a client: the Companies House lookup, by name, from QuickBooks or Xero, or the full details form. Then what to complete before you file.

When Corporation Tax is due, where to find the amount and date in Tax Optimiser, quarterly instalments for large companies, and how to record what has been paid.

Adding partners, boxes 6-12, entering each partner's share, and the live checks: the allocation-vs-return warning and the UTR check that prevents error 8205.

The cost, amortisation and net book value table for goodwill and other intangible assets, built from the trial balance.

Read the cross-referenced computation, finish the statutory accounts, and clear the validation checks.

Who can skip an audit, when shareholders can insist on one, and the statement the directors must sign.

Mark rental income and letting costs as UK property in the P & L, and Tax Optimiser reports the property business in boxes 190, 805 and 250 - separately from the trade.

Where annual payments, non-exempt dividends from overseas companies and income received net of Income Tax go on the CT600 - boxes 175, 180 and 185 in Tax Optimiser, with a worked example.

Enter a year-end adjustment as debits and credits, approve it, and see exactly what it changed.

A breakdown of the balance sheet debtors figure into trade debtors, group and related amounts, prepayments and other debtors.

The Freeports and Investment Zones supplementary page - when the CT600M is needed, the two enhanced allowances, how to complete it in Tax Optimiser and what each box from M1 to M30 means.

The 45% charge on restitution interest paid by HMRC - when the CT600K is needed, how to complete it in Tax Optimiser and what every box from K1 to K35 means.

An optional text note describing what the company's turnover is made up of.

The controlled foreign company charge, the foreign branch exemption election and hybrid mismatch disclosures - how to complete the CT600B in Tax Optimiser and what every box from B1 to B85 means.

How to add a second company to the Tax Optimiser login you already have, finish its details, and switch between your organisations.

Every set of accounts and every CT600 hangs off an accounting period. Here is how the system creates them for you automatically from Companies House, and how to add one by hand when you need to.

Disclose material arrangements that are not on the balance sheet but expose the company to risks or benefits.

The fair value reconciliation for property held to earn rent or for capital growth, with the basis of valuation.

The end-of-year additions - dividends, foreign income, pensions, reliefs - that complete the year before your tax is worked out.

The once-a-year declaration that crystallises your tax bill, what must be done first, and how to re-open a year to amend it.

Reporting a DOTAS Scheme Reference Number on the Company Tax Return - when the CT600J is needed, how to complete it in Tax Optimiser and what every box from J1 to J50A means.

State that the company has no share capital and how much each member guarantees on a winding up.

The full SA800 income and expenses page: entering income and expense totals, the capital allowance pools, an optional breakdown of disallowables, and how the calculated boxes 3.65 and 3.73 drive the rest of the return.

How quarterly figures get into Tax Optimiser: uploading a spreadsheet, the full and consolidated example templates, and mapping your own cells.

The R&D supplementary page of the Company Tax Return: who has to file one, how the seven RDEC steps turn a claim into cash, and what every box from L5 to L210 means.

Depreciation in the accounts is not deductible for Corporation Tax. How to add it back in Tax Optimiser, record your fixed assets so capital allowances replace it, and reverse profits or losses on disposal.

The Details step: partnership name and live-checked UTR, boxes 3.1/3.2, period and start/cessation dates, the accounting basis and declarations, the page 2 questions and box 3.116.

How the stock figure on your balance sheet is split into raw materials, work in progress and finished goods, straight from the trial balance.

How to authorise Tax Optimiser to talk to HMRC, the difference between an individual and an agent connection, and when to reconnect.

Sending a quarterly update: reading the values, confirming the declaration, and amending a quarter after it has gone.

The 4% tax on residential property development profits above a £25 million group allowance - when the CT600N is needed, how to complete it in Tax Optimiser and what every box from N1 to N285 means.

Where the firm's Presenter ID and Government Gateway login live, what each one is, and how to obtain a Presenter ID.

Prepare and file full SA100 Self Assessment returns for clients not in MTD — with a live tax calculation — from inside Tax Optimiser. Beta access via support@taxoptimiser.co.uk.

Two versions of one set of accounts: what filleting removes, where each version is filed, and how amended filings work.

Asking HMRC to work out the tax on what you have reported, the three kinds of calculation, and how to read the result.

Accepted years lock; Reopen for amendment files a replacement return. The amendment deadline, rejections, and chasing stuck submissions.

Square off a penny of rounding, or change how a balance is shown, without touching your bookkeeping.

The checks that block a return HMRC would reject (each linked to its step), the page 8 declaration, the review summary, printing the official SA800 form and its schedule, what Submit really does, and what happens afterwards.

The tonnage tax supplementary page - when the CT600F is needed, how the profit for each ship is worked out, how to complete it in Tax Optimiser and what each box from F1 to F70 means.

Filing the CT600 for a client: the UTR and Gateway login it needs, what the warnings mean, and the final confirmations before sending.

Filing a prepared return: the pre-flight checks and their fix links, the declaration, what happens during submission, and reading the submission history.

Land & Property, Foreign, Chargeable Assets and Savings on one screen - each page files only when it carries figures, and the totals calculate themselves.

A one-sentence statement that the accounts follow FRS 102 Section 1A, which Tax Optimiser fills in for you.

Where your personal details go, and why your National Insurance Number is required before any submission.

How a company gets money back from its Company Tax Return - R&D and creative credits paid in cash, Income Tax repaid, bank details - and what every CT600 repayment box from 860 to 970 means.

Explain a corrected prior period error or a change of accounting policy, and the amounts restated.

Stuck on something? Raise a support case from inside Tax Optimiser. Attach screenshots, get an email when the support team replies and keep the whole conversation in one place.

The opening note that identifies the company: its name, legal form, where it is registered, its number and its registered office.

AVEC, VGEC and the creative reliefs - how an expenditure credit becomes a payable credit, how to claim it in Tax Optimiser and what every box on the CT600P means.

Pension contributions, Gift Aid, Marriage Allowance, the High Income Child Benefit Charge, student loan plans, and the return's closing boxes.

Disclose listed shares and other financial assets carried at fair value, the gain or loss for the year and how they were valued.

The per-business settings that shape how figures are reported: cash or accruals accounting, standard or calendar quarters, and full or consolidated expenses.

Every period follows the same three stages before you can file: get the trial balance in, build and review the accounts, and build the Corporation Tax computation. Here's the map.

Opening a client's first Self Assessment year, the pre-filled personal details, choosing the return's pages with Add Section, moving between sections, and the save-as-you-go model.

Show the historical cost comparison and the revaluation reserve movement for fixed assets carried at a valuation.

How Tax Optimiser retrieves your income sources from HMRC, the three business types, and what each business holds.

Send a period's accounts and Company Tax Return to your client from the period Overview. They read, sign and approve online, or ask a question, and cannot open or change anything else.

Find your way around the View Accounts screen: the live preview, page links and the editing actions.

Bring a year's figures in from Xero, Sage 50 or any spreadsheet, map them to HMRC and Companies House-ready accounts with AI help, and make it balance.

Your accountant has sent you accounts or a tax return to approve. Sign in, read each document, then sign and approve, or send a question back.

Need fuller accounts than FRS 105 allows? Switch the period's Accounts Type to FRS 102 Section 1A from the Overview and keep your trial balance, journals and tax computation.

Clear the validation list, record who signed and when, and keep the signed copy on file - then you are ready to submit.

How a company carries a trading loss back against earlier profits - the 12-month carry-back, three-year terminal loss relief when the trade stops, the Carry back to earlier periods panel, amending earlier returns, and CT600 boxes 45, 275, 280 and 780.

The one-off fee a company pays to file a period: how much, when you are asked, how to pay and where to find the receipt.

Looking for a CT600 or a set of accounts you have already filed? Where to find it in Tax Optimiser, how to read the status and how to download a copy.

What companies and accountant firms pay for in Tax Optimiser: per-period fees or credits for year-end filing, and a subscription for VAT and MTD.

The four FRS 105 notes explained, including the mandatory average-employees figure and how wording templates work.

How the note set grows under FRS 102 Section 1A, which notes fill themselves from the trial balance, and the accounting policies window.

When a company's accounts cover more than 12 months, Tax Optimiser keeps one set of statutory accounts but splits the Corporation Tax into two CT600 returns - the first 12 months and the remainder. How the split is decided, how profits, capital allowances and losses are divided, and how both returns are filed.

How statutory accounts for a limited liability partnership differ from company accounts in Tax Optimiser: members and designated members, no directors' report or tax line, members' interests on the balance sheet, the reconciliation of members' interests, and one credit covering the accounts and the SA800.

A CIO files a CT600 but nothing at Companies House, and its SORP accounts go to HMRC as a PDF. Here is the whole journey, from signing up to sending the return.

Set the organisation's Corporation Tax company type to Charity or CASC and the CT600E supplementary page appears, ready to complete and file with the CT600. A company only owned by a charity has its own company type and files no CT600E.

The VAT and MTD subscription: the free period, adding or changing a card, finding invoices, changing the billing contact and cancelling.

Mark a company's accounts as audited or as an audit exempt subsidiary (s479A): the auditor's details, the four opinion types, and what changes in the accounts and the iXBRL. In beta for accountant firms.

Manage the directors list, sync it from Companies House, and designate who signs the balance sheet.

How accountant firms pay for year-end filing: Active and Dormant credits, the packs, exactly when a credit is used, and the purchase and consumption history.

Write the strategic report that medium and large companies must include, and small companies may: the sections, the templates, moving directors' report matters, approval and the checks. In beta for accountant firms.

The Company Information, Dates, Pages and Addresses windows - the descriptive details that appear throughout the document.

Add free credits with a gift code, and earn credits by sharing your firm's referral code.

Worked trial balances for a dormant company: never traded, used to trade, subsidiary, investment holder, director's loan and Companies House fees.

How to correct a Company Tax Return that HMRC has already accepted: the two-year limit, Submit as amended, returns first filed elsewhere, and what to do when the window has closed.

From the balance sheet to Send Accounts: every screen for a company that was dormant all year.

When no CT600 is needed, when a nil return is, and how to handle a company that was dormant for only part of the year.

Prepare a small company's accounts under full FRS 102: a statement of changes in equity and a cash flow statement, plus staff costs, directors' remuneration, tax reconciliation, reserves and financial instruments notes. In beta for accountant firms.

The yearly duties of a dormant company at Companies House and HMRC, and which ones Tax Optimiser files.

Prepare a charity's accounts in charity format: a Statement of Financial Activities by fund, a trustees' annual report and an independent examiner's report under the Charities SORP, or receipts and payments accounts for a small charity that is not a company. In beta.

Switch on the VAT service, enter your VAT registration number and find your way around.

Tell Tax Optimiser which sheet and cells of your spreadsheet hold the nine VAT-return boxes.

Accept the declaration, get HMRC's acceptance back and keep the receipt as proof of filing.

A step-by-step guide to the Imported Data tab: matching each imported account to a common account by hand or with AI suggestions, and checking the result.

HMRC rejected the CT600? What errors 3304, 1611, CTISS002 and an authentication failure mean, why they happen and how to fix each one.

Drag your spreadsheet onto the open period and check the nine boxes it fills.

Practise the HMRC connection in demo mode, then go live with your firm's agent account and let the client's periods flow in.

Track what HMRC says you owe and have paid, and settle into the quarterly routine.

Upload the client's spreadsheet, check the nine boxes, accept the declaration and keep HMRC's receipt.

Practise the HMRC connection in demo mode, then grant authority for real and let your periods flow in.

Tell Tax Optimiser which sheet and cells of the client's spreadsheet hold the nine VAT-return boxes.

Give a client a login to their own organisation - they only ever see the organisations they belong to.

How filing VAT for clients works in Tax Optimiser - what you set up once for the firm and what you do for each client.

Add a client organisation from your Organisations list - only the VAT registration number is required.

Add colleagues to your firm so they can act for your clients with their own login.

Four ways to get a year's figures into Tax Optimiser, how to choose, and a walkthrough of Simple Entry: numbered boxes for micro-entity accounts and Corporation Tax, from first figure to filing.

Every Community Interest Company must send a CIC34 report to Companies House with its accounts each year. What goes in it, when it is due, the fee, and how to file it online or by post.

A Community Interest Company files the same CT600 and accounts as any company. The difference is the CIC34 report it sends to Companies House each year - here is how to prepare it in Tax Optimiser.