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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.

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.

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.

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

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.

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

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

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.

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.

Need fuller accounts than FRS 105 allows? Switch the period's Accounts Type to FRS 102 Section 1A from the Overview, then re-enter or re-import the figures it clears.

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.

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

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.

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

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.

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

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

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.

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.

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.

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

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.

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.

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.

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

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.

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

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

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

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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

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

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

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.

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.

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.

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.

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.

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

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.

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.

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

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

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

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

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

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

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

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.

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.

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.

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.

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

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

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.

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.

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

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

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

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

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.

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

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

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.

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.

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.

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.

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

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

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.

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.

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.

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

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

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

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

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.

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.

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.

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.

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

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

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

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.

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.

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.

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

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

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

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.

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.

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

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.

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.

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.

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.

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

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.

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

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

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.

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.

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.

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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.

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.