Cash vs Accrual Accounting Under MTD: Choosing the Right Basis and Practical Implications

Why this matters now: the 2026–2028 MTD ITSA rollout

Making Tax Digital for Income Tax Self Assessment, often shortened to MTD ITSA, is being introduced in stages. From April 2026 those with income above £50,000 will need to comply. From April 2027 the threshold falls to £30,000, and from April 2028 it reaches £20,000. If you are self-employed or a landlord, this means most small businesses will soon need to keep digital records and send quarterly updates alongside a final year-end declaration.

Cash basis versus accruals: the simple difference

Choosing between cash accounting and accrual accounting is one of the first practical decisions you must make for tax. The core difference is straightforward.

• Cash basis records income when money actually hits your bank and expenses when you actually pay them. It is simple and follows your cashflow.
• Accruals (also called the invoice or traditional basis) records income when you invoice a customer and expenses when you receive an invoice from a supplier, regardless of when cash moves.

MTD does not force a change of accounting basis. However, the basis you choose affects how you keep digital records, the timing of your tax liabilities, and the way you prepare quarterly updates under MTD ITSA.

Which businesses typically use each basis?

• Cash basis is commonly used by smaller unincorporated businesses and many landlords because it is easier to operate and reflects cash available to the business.
• Accruals tend to suit businesses with stock, significant credit terms, regular work-in-progress, or those that need accurate income- and expense-matching for management information.

How the choice affects your MTD ITSA quarterly updates

Under MTD ITSA you will be making four quarterly updates and then a final end-of-period statement and declaration at the year end. The basis you use determines which transactions appear in each update.

• If you use the cash basis, you report cash receipts and payments in the period in which they actually occurred. Quarterly figures will match your bank statements more closely.
• If you use accruals, you report income when invoices are raised and expenses when bills are received. That means a quarter with many invoices raised will show higher income even if cash comes later.

Practical example: why timing matters

Imagine you are a self-employed consultant who invoices a client 29 March for 5,000 and the client pays on 10 April. Under accruals that income belongs to the earlier accounting period; under cash basis it belongs to the period when payment arrives. The effect can be that a taxable gain appears in one year on accruals but in the next year on cash basis, which changes when tax is payable.

Common situations where choice matters

• Late payments — if your customers are slow to pay, accruals can show profit you do not yet have in cash.
• Large prepayments or deposits — accruals may require you to recognise income earlier.
• Stock and work-in-progress — businesses holding inventory usually need accruals so stock is valued at period end.
• Capital spending — capital allowances rules sit alongside your basis. The way you treat fixed assets will differ and needs careful handling when you change basis.

Landlords: a note on rental income and deposits

If you are a landlord, your choice affects how you report rent received and certain costs. Rent paid in arrears versus in advance, tenancy deposits handled as non-taxable or taxable receipts, and repair timing all influence whether the cash or accruals basis better reflects your situation. Many landlords choose the cash basis because it aligns with tenancy payments, but if you manage multiple properties, have large repairs or capital works, or hold insurance claims that cover costs, accruals can sometimes be more accurate for accounting purposes.

What MTD requires of your records, irrespective of basis

MTD ITSA focuses on digital records. Whether you are on cash or accruals, HMRC requires that you maintain digital records that can be linked to commercial MTD-compatible software for quarterly submissions. Practically this means:

• Digital copies of invoices and bills, not paper-only ledgers.
• Electronic records of receipts and payments if using cash basis, or invoice and bill records if using accruals.
• Clear categorisation of income and expense types so quarterly updates include the right totals.

Can you switch between cash and accruals?

Yes, you can change basis, but there are rules and consequences. Changing basis affects how you treat opening and closing balances and may require transitional adjustments to avoid double counting or omitting income or expenditure. You should:

• Discuss the change with your accountant before implementing it.
• Keep careful records of the reason and date of change.
• Make any necessary adjustments on your tax return so neither year is unfairly taxed or relieved.

Choosing the right basis: a practical checklist

Use this checklist to decide which basis is likely to suit your business under MTD ITSA.

• How regular are your receipts? If clients pay quickly and you prefer simplicity, cash basis is attractive.
• Do you hold stock or have long contracts? Accruals usually give a truer picture of profit.
• What does your cashflow look like? If timing of tax payments is a concern, cash basis can smooth tax due on late-paid income.
• Are you planning to claim capital allowances or have large equipment purchases? Speak to an accountant — the timing of reliefs differs between bases.
• How complex are your books? If you prefer fewer end-of-period adjustments, cash basis reduces year-end reconciliations.
• Can your accounting software handle the basis and MTD submissions? Ensure your software supports the necessary reporting and digital linking.

Accounting software: features to look for

Under MTD you must use MTD-compatible commercial software. When choosing software to support either basis, look for:

• Explicit support for both cash and accrual reporting and the ability to switch with guidance.
• Automated bank feeds and rule-based transaction categorisation to reduce manual work.
• Easy preparation of the quarterly updates required by MTD ITSA and the end-of-period statement.
• Good tagging, project and property modules if you run multiple activities or manage several rental properties.
• Secure digital attachments for invoices and receipts so your records are complete for HMRC checks.

Practical steps to prepare before your first MTD quarterly update

• Decide your accounting basis with your accountant and document that decision.
• Choose MTD-capable software that suits your business needs and test it with sample transactions.
• Digitise historical paperwork and ensure your current year transactions are recorded in the chosen system.
• Reconcile bank accounts and check that categories for tax purposes are correct.
• Run a mock quarterly update so you know what figures will be submitted and what follows at year-end.

Common pitfalls and how to avoid them

• Mistaken timing — confuse invoice dates and payment dates. The software should be set to the correct basis so numbers appear in the right quarters.
• Missing digital links — MTD submissions require digital records that link to your software. Avoid paper-led systems or unlinked spreadsheets.
• Ignoring capital allowances — equipment and vehicle costs are handled differently to everyday expenses. Get guidance before deducting large purchases.
• Assuming one size fits all — what works for a sole trader with simple income may be unsuitable for a landlord with multiple properties or a trading business with stock.

What to tell your accountant

When you speak to your accountant about MTD and the basis choice, be ready to provide:

• Details of your trading pattern and cashflow timing.
• Examples of invoices issued close to period ends and any long payment terms.
• Information on stock, work-in-progress or significant repairs and capital expenditure.
• Any plans to change trading structure or take on new properties or contracts.

Final practical tips and reassurance

The move to MTD ITSA is a change in process rather than a sudden new tax. Your accounting basis will influence the timing of tax rather than the overall tax due in most cases. The right software, good record-keeping and early conversations with your accountant make this transition manageable. If you keep basic digital records now and test a quarterly submission, you will have confidence before your required start date.

Tax Digital helps clients choose and implement the right basis, select compatible software and set up a steady workflow that keeps quarterly updates accurate and painless. We take the stress away and make compliance easy.