Self Assessment Record Keeping Guide

Why your records matter

Every figure on your tax return has to be backed by something. Your records are the evidence for the income you declare and the expenses you claim, and they are what you fall back on if HMRC opens a check. Good records also make the return itself far quicker to complete, because the numbers are already there.

The habit starts the moment you register for Self Assessment and runs for as long as you trade. It sits underneath everything else, from working out a payment on account to correcting a figure later.

How long to keep your records

If you are self-employed, HMRC asks you to keep your records for at least five years after the 31 January submission deadline for the relevant tax year. So records for the 2024 to 2025 return, filed by 31 January 2026, must be kept until at least 31 January 2031.

People who are not in business but still file a return, such as employees or pensioners with some untaxed income, keep records for around 22 months after the end of the tax year. If you send a return more than four years late, keep the records for 15 months after you file.

• Self-employed or a landlord: five years after the 31 January deadline.
• Not in business but filing a return: about 22 months after the tax year ends.
• Return filed very late: 15 months after the date you send it.
• Under enquiry: keep everything until HMRC confirms the check is closed.

What records to keep

You need enough to show your income and your allowable expenses. On the income side that means your sales or fees, along with anything else taxable such as bank interest, dividends or rental income.

• Income: invoices you issue, till or sales records, and statements from any platform that pays you.
• Bank and card statements for the business, plus records of any cash taken.
• Expenses: receipts and invoices for anything you claim, kept in date order.
• A mileage log if you claim for a vehicle, with dates, journeys and business miles.
• Records of anything you use for both work and private life, so you can show the split.

For use of home you can either work out the actual business share of your bills or use HMRC simplified flat rates: 10 pounds a month for 25 to 50 hours worked at home, 18 pounds for 51 to 100 hours, and 26 pounds for 101 hours or more. Keep a note of the hours either way.

Cash basis is now the default

From the 2024 to 2025 tax year the cash basis is the default way most sole traders and partnerships work out profit. You record income when the money actually reaches you and expenses when you actually pay them, rather than by invoice date. The old turnover limits for using it have been removed, so a business of any size can use it unless it elects for traditional accruals accounting instead.

This matters for record keeping because it ties your figures to your bank account rather than to a ledger of unpaid invoices, which is far simpler to evidence.

Digital records and Making Tax Digital

Making Tax Digital for Income Tax changes how records are kept for larger sole traders and landlords. It applies from 6 April 2026 where qualifying income from self-employment and property is over 50,000 pounds, from April 2027 where it is over 30,000 pounds, and from April 2028 where it is over 20,000 pounds. Qualifying income is measured on gross income before expenses.

Once you are inside Making Tax Digital you must keep your records digitally in compatible software and send quarterly updates to HMRC, rather than pulling a shoebox of receipts together once a year. Photographs of receipts are accepted, as long as they are legible and kept.

If your income is below the thresholds you are not caught yet, but moving to digital records now makes the eventual switch painless and gives you a clearer view of your position through the year.

Keep business and personal money apart

The single change that saves the most time is a separate bank account for the business. It removes the guesswork of picking business transactions out of personal spending, and it makes reconciliation quick. If you do pay for something business-related from a personal account, note it so it is not lost.

Clean separation is also what lets your records support later decisions, such as when you reduce your payments on account because profits have fallen. Without solid figures you are guessing, and guessing wrong carries interest.

The penalty for poor records

HMRC can charge a penalty of up to 3,000 pounds for failing to keep or preserve adequate records, under section 12B of the Taxes Management Act 1970. In practice the maximum is reserved for serious cases, such as records deliberately destroyed, but weak records cause a bigger day-to-day problem. Expense claims you cannot back up may be disallowed, and HMRC can raise an assessment based on its own estimate of your income.

Good records also protect the right to put things right. You have twelve months from the filing deadline to correct a mistake on a submitted return, but only if the paperwork supports the change.

A simple monthly routine

Record keeping is far easier as a small monthly habit than as a January panic. A workable routine looks like this.

• Reconcile the business account against your records so nothing is missing.
• File the month's receipts and invoices, digitally where you can.
• Update your mileage log while the journeys are still fresh.
• Set aside the tax you have earned that month so it is there in January.
• Note anything unusual, such as a large one-off cost, while you remember the detail.

Half an hour a month keeps the records complete and the eventual return straightforward, and it means the figures are ready if HMRC ever asks to see them.

Frequently asked questions

How long do I have to keep my Self Assessment records?

If you are self-employed or a landlord, at least five years after the 31 January submission deadline for that tax year. If you are not in business but still file a return, keep them for around 22 months after the end of the tax year.

Can I keep everything digitally?

Yes. HMRC accepts digital records and photographs of receipts, provided they are legible and complete. From April 2026, businesses inside Making Tax Digital for Income Tax must keep digital records in compatible software.

What records do I actually need to keep?

Enough to evidence your income and your allowable expenses: invoices and sales records, bank statements, receipts, a mileage log if you claim for a vehicle, and records of anything used for both work and private life.

What happens if I lose some records?

Recreate what you can from bank and card statements and note where a figure is estimated. Persistently inadequate records can lead to a penalty of up to 3,000 pounds and to expense claims being disallowed, so rebuild the trail as far as you can.

Do I need software to keep records?

Not unless you are within Making Tax Digital for Income Tax, which requires compatible software. Below the thresholds a spreadsheet is fine, though moving to software early makes the later switch simpler.