by Asim Abbas
12 November 2026 
Making an HMRC disclosure with missing records: how to use estimates properly
Making an HMRC disclosure with missing records: how to use estimates properly
Many people delay a disclosure because their records are incomplete. HMRC accepts that this happens: you can use reasonable estimates, as long as you keep your workings.
- Include only income, gains and tax you have not declared before.
- If records are incomplete, use reasonable estimates and keep your workings.
- Ask your bank for old statements to fill gaps.
- Failing to keep proper records can bring a penalty of up to £3,000.
- HMRC’s online calculators cover tax years ending 5 April 2010 to 5 April 2024.
What matters is that the figures are honest, sensible and explained. A careless estimate can lead HMRC to reject the disclosure.
This guide explains how to rebuild your figures, based on HMRC’s guide to making a disclosure.
What goes into the disclosure
According to HMRC’s guide, include only income, gains and tax you have not declared before. Income you have already declared stays out. Current-year income goes on your normal tax return, and income for the previous year should go on a return if you are still within 12 months of the filing date.
Common items include undeclared self-employed income, rental income (after allowable expenses), investment income, capital gains and, for companies, overdrawn director’s loans and understated profits.
Using estimates
If your records are incomplete, you can estimate, but you must keep your workings. Good estimates are based on evidence, not guesses:
- bank statements: ask your bank for copies of old statements
- rental records: tenancy agreements, letting agent statements and deposit records
- online platforms: sales histories from marketplaces and payment apps
- crypto: exchange transaction downloads, even for closed accounts where possible
- property sales: completion statements and Land Registry records
Where a figure has to be estimated, use a reasonable method and apply it consistently across the years, and write down how you reached it.
Estimate your disclosure
Our free HMRC disclosure calculator works out tax, interest to today and penalties for each year, with PDF or CSV download.
The record-keeping penalty
Failing to keep proper records can lead to a penalty of up to £3,000. Once you have made your disclosure, keep good records going forward, because HMRC expects your later years to be accurate.
HMRC’s calculators
HMRC’s underpaid tax service offers calculators for straightforward cases. The tax, interest and penalty calculator covers tax years ending 5 April 2010 to 5 April 2024, and the interest and penalty calculator covers years ending 5 April 2006 to 5 April 2024. They assume basic personal allowances only, so they are not suitable for more complex affairs.
Fixed-fee accountancy support
Transparent monthly packages for sole traders, landlords and limited companies. Fixed fees agreed upfront, VAT included.
Get a fixed-fee quoteCall 0161 531 4179Tax credits and benefits
If you received tax credits during the years being disclosed, you should still disclose and tick the relevant box, as extra income may affect what you were entitled to.
How we help
We rebuild missing figures from bank statements and third-party records, document our method so HMRC can follow it, and calculate the tax, interest and penalty for each year. Read our guides to how many years to disclose and the Digital Disclosure Service.
Voluntary disclosure help near you
We help clients make disclosures across the UK, including London, Manchester, Birmingham, Leeds, Liverpool, Bristol, Newcastle, Cardiff and Wales, and in Scotland from Glasgow to Edinburgh. Start with our voluntary tax disclosure service.
What should I do next?
Start now, as banks can take weeks.
Including rental, online sales and crypto.
Apply it consistently and write it down.
We prepare figures HMRC can follow.
Frequently Asked Questions
Can I make a disclosure without full records?
Yes. You can use reasonable estimates if you keep your workings and can explain your method.
How do I get old bank statements?
Ask your bank for copies. Many banks can provide several years of statements.
Is there a penalty for poor records?
Failing to keep proper records can lead to a penalty of up to £3,000.
Should I include income I have already declared?
No. Only include income, gains and tax you have not declared before.
Can I use HMRC’s calculators?
For straightforward cases only. They cover limited years and assume basic personal allowances.
Need help with this? Wingate Accountants offers fixed-fee online accountancy support across the UK. Call 0161 531 4179 or request a quote at wingateaccountants.co.uk.
About the Author
Stephen Reynold
I’m Stephen Reynold, an accountant at Wingate Accountants. I work with sole traders and small companies, turning tax rules into clear, practical next steps.
