HMRC Record-Keeping Standards for MTD: What You Must Keep

Why Record-Keeping Matters More Under MTD

Filing quarterly updates is only half the job. The other half is keeping the records that prove those updates are correct. HMRC's Compliance Handbook sets out what "adequate records" looks like in practice - and for MTD-mandated sole traders and landlords, the standards are specific. This post explains what you must keep, for how long, and what happens during an enquiry if your records fall short.

What HMRC Means by "Adequate Records"

HMRC does not give you a precise list of documents and say "keep these, nothing else matters." Instead, the Compliance Handbook describes adequate records as those that are sufficient to allow a complete and accurate tax return to be prepared. That is a functional test, not a checklist.

In practice, this means your records must:

• Show all income received, with dates and amounts
• Support every expense claimed, with evidence it was incurred for business purposes
• Be accurate enough that HMRC could reconstruct your figures if they chose to
• Be legible and accessible - not just "somewhere on your phone"

Under MTD, this standard applies to each quarterly update, not just the final declaration at the end of the tax year. If you file a Q1 update and HMRC opens an enquiry six months later, you need to be able to produce the records that supported that specific quarter's figures.

Retention Periods: How Long Must You Keep Records?

The retention rules depend on who you are and what kind of income you have.

Sole traders

If you are self-employed, you must keep business records for at least five years after the 31 January filing deadline for the relevant tax year. So for the 2026-27 tax year (with a final declaration deadline of 31 January 2028), you must keep records until at least 31 January 2033.

Landlords

Property income records follow the same five-year rule for most landlords. However, if your tax return was filed late, the clock starts from when HMRC received the return, not from the standard deadline. That can push your retention obligation out further than you might expect.

When HMRC opens an enquiry

If HMRC opens a formal enquiry, you must keep all relevant records until the enquiry is fully closed - regardless of how long that takes. A five-year-old record you were about to delete could become essential evidence if an enquiry is still in progress.

What Documents Matter Most in an Audit

When HMRC examines your records, some documents carry more weight than others. Knowing which ones to prioritise makes a real difference if you are ever asked to substantiate your figures.

Income records

• Invoices issued - for sole traders, these are primary evidence of income earned
• Bank statements - HMRC will typically compare your declared income against money received
• Rental agreements - for landlords, these establish the agreed rent and the period it covers
• Rent receipts or payment records - showing what was actually received and when
• Cash income records - if any income was received in cash, you need a record of it

Expense records

• Receipts and invoices received - ideally showing the supplier, date, amount, and what was purchased
• Mileage logs - if you claim mileage using simplified rates, a log showing dates, destinations, and business purpose is essential (see our post on mileage allowances for MTD)
• Bank statements - to corroborate expense payments
• Credit card statements - where business costs were paid by card
• Mortgage statements - for landlords claiming finance costs or tracking capital vs revenue

Records that support adjustments and allowances

If you claim capital allowances, the property allowance, trading allowance, or use of home as office, you need records that justify the amounts. HMRC pays close attention to these areas because they are common points of error or overstatement.

For landlords, records of repairs versus improvements are particularly important. Repairs are allowable expenses; improvements to the property are not. If HMRC questions a cost, you need evidence of what was actually done. A contractor invoice with a description goes a long way.

Digital Records vs Paper: What MTD Actually Requires

MTD does not ban paper entirely, but it does change how your records must flow into your quarterly update.

What must be digital

Under the MTD rules, you must keep a digital record of each transaction, and data must flow between your software by digital links once it is in your records. This includes:

• Gross income from self-employment or property
• Allowable expenses, categorised correctly
• Any adjustments made within your software

If you keep a spreadsheet and use bridging software like Affordable MTD to submit, the spreadsheet itself counts as your digital record. The data does not need to live inside a full accounting package - it just needs to exist in a digital format that feeds into your submission.

What paper records are still acceptable

The underlying source documents - your receipts, invoices, and bank statements - can still exist in paper form. HMRC accepts paper receipts as supporting evidence. The requirement is for a digital record of each transaction (date, amount and category), not a scan of every receipt.

That said, digitising your receipts is a practical safeguard. Paper fades, gets lost, and is awkward to produce quickly if HMRC asks. A scanned copy stored alongside your digital records is far easier to manage.

Digital links: no copy and paste between systems

Typing transactions into your digital records (for example, entering each receipt into a spreadsheet) is allowed. What MTD rules prohibit is manually moving data between digital systems once it is in your records - retyping or copying and pasting figures from one spreadsheet or app into another. Those transfers need a digital link, such as a formula, an import or bridging software.

How Long to Keep Digital Records Specifically

The same five-year retention rule applies to digital records as to paper. Closing an account or switching software does not end your obligation. Before you leave any platform, make sure you export your records in a format you can access later - ideally a PDF summary and a CSV export of all transactions.

HMRC has made clear that if your digital records become inaccessible - because a subscription lapsed, a hard drive failed, or a service shut down - that is your problem, not theirs. Back up regularly and keep copies in more than one place.

Record-Keeping for Mixed Income: Sole Traders Who Are Also Landlords

If you have both self-employment income and property income, you must keep separate records for each. HMRC treats these as distinct income streams, and your quarterly updates for each must be supported by their own records.

This means separate expense records, separate income logs, and ideally a clear way of distinguishing any costs that are shared (such as a home office used partly for your business and partly for property management). Costs that straddle both income sources need to be apportioned reasonably and documented. See our post on managing multiple income sources under MTD for more detail.

What Happens If HMRC Decides Your Records Are Inadequate

If HMRC opens an enquiry and concludes that your records are inadequate, they have several options. They can:

• Issue a discovery assessment based on their own estimate of your income
• Disallow expenses where there is no supporting evidence
• Charge penalties for careless or deliberate inaccuracy
• Issue a record-keeping penalty of up to £3,000 for failing to keep adequate records

The record-keeping penalty is separate from any penalty for underpaying tax. You can be fined for poor records even if HMRC ultimately agrees that your tax figures were correct.

Our guide on responding to HMRC rental income enquiries covers what the process looks like if you do receive a letter, and our post on records to keep for rental income enquiries goes deeper on the property side specifically.

How Affordable MTD Supports HMRC's Record-Keeping Standards

Affordable MTD stores the data behind every quarterly update you submit. That means your income figures, expense categories, and submission history are kept within the platform and can be reviewed at any time.

Here is what that covers in practice:

• Submission records - every quarterly update you file is logged with a timestamp and confirmation reference
• Income and expense data - the figures you submitted are stored against the relevant quarter
• CSV import history - if you uploaded transaction data, that upload is retained
• Amendment records - if you corrected a quarterly update, the amendment is logged alongside the original

What Affordable MTD does not store is your underlying source documents - your invoices, receipts, and bank statements. Those remain your responsibility to keep, whether in paper or digital form. The platform handles the submission layer; you handle the evidence layer.

If you are preparing for a potential enquiry, the combination of your own stored receipts and Affordable MTD's submission records gives HMRC a clear audit trail from source document to submitted figure. That is what "adequate records" looks like in practice.

For a broader guide to setting up a system that keeps all of this organised, see our post on setting up your MTD bookkeeping system.

Practical Steps to Get Your Record-Keeping Right

You do not need a complex system. You need a consistent one. Here are the steps that make the biggest difference:

1. Digitise receipts as you go - photograph or scan each receipt when you receive it, not at the end of the quarter
2. Keep income and expense records separate by quarter - a simple folder structure (Q1, Q2, Q3, Q4) works fine
3. Reconcile your bank statement monthly - catch anything missing before it becomes a problem
4. Keep a mileage log if you drive for business - a basic spreadsheet with date, destination, and purpose is enough
5. Do not delete old records - set a calendar reminder for the five-year mark, then review before disposing
6. Back up digital records in at least two places - cloud storage plus a local copy is a sensible minimum
7. Export your data before switching software - never leave a platform without taking your records with you

If your records are currently in a mess and a deadline is approaching, see our post on fixing messy expense records before a quarterly deadline.

Summary

HMRC's record-keeping standards for MTD come down to one test: can you prove your figures? That means keeping income and expense records that are accurate, dated, and accessible - for at least five years from the relevant filing deadline. Digital records must flow into your quarterly updates through digital links, not copy and paste. Paper receipts are still acceptable as supporting documents, but digitising them makes everything easier. If HMRC opens an enquiry, strong records protect you from estimated assessments, disallowed expenses, and penalty charges. A consistent system, maintained week by week, is far less work than reconstructing records under pressure.