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Explain My HMRC Letter

What each common HMRC letter means, how to recognise it, what to do and by when, what happens if you ignore it, and the official GOV.UK page. Pick your letter below.

By The HandySums teamLast checked:
Plain EnglishNo jargon, with the deadline up front.
Scam-awareEvery page tells you how to check a letter is genuine.
No uploadsWe never ask for your letter, a photo or a password.

Beware of HMRC scam letters, emails and texts

Do not upload, photograph or send any letter to us or to anyone you are not sure of. This site never asks for your letters. Scammers copy HMRC letters. If something rushes you, threatens you or asks for money or bank details, stop.

It could be a scam if it:

  • It rushes you or sets a short deadline.
  • It threatens you, for example with arrest or legal action.
  • It is unexpected.
  • It asks for personal information such as bank details.
  • It tells you to transfer money.
  • It offers a refund, tax rebate or grant.

What HMRC says:

  • HMRC will only email you about a tax rebate, or ask for personal or payment information, from an address ending hmrc.gov.uk.
  • HMRC never uses social media to offer a rebate or ask for personal or financial information.
  • HMRC will never ask you to pay with gift or payment vouchers.
  • HMRC never leaves voicemails threatening legal action or arrest.
  • HMRC does send some text messages and may include a link to GOV.UK or HMRC webchat, but do not open links in a text that offers a refund in exchange for personal or financial details.
  • Letters may contain QR codes. They usually go to GOV.UK, and HMRC tells you if not. A genuine one never takes you to a page asking for personal information.

How to report it:

  • Emails: forward to phishing@hmrc.gov.uk, then delete.
  • Texts: forward to 60599 (your network rate applies) or email phishing@hmrc.gov.uk.
  • Phone calls: use the "Report a suspicious HMRC phone call" online service.
  • Social media accounts: email branddefence@hmrc.gov.uk.
  • If you have lost money, report it to Report Fraud, or to Police Scotland on 101 in Scotland.

Check the list of genuine HMRC letters on GOV.UK and the scam checklist. When in doubt, sign in to your HMRC online account yourself rather than using a link.

Pick your letter

Late filing penaltySelf Assessment late filing penalty noticeHMRC charges an automatic penalty when a Self Assessment return is filed late, even if you owe no tax.SA statementSelf Assessment statement and balancing paymentThe statement shows what you owe HMRC at the time it was sent: your balancing payment, any payments on account, anything left over from earlier years, and payments you have made (shown as CR).Payment reminderPayment on account and January payment remindersA reminder is HMRC nudging you to pay by 31 January.Notice to fileNotice to file a Self Assessment tax returnA Notice to File is HMRC's formal request that you complete a Self Assessment return (HMRC form SA316).Simple AssessmentSimple Assessment letter (tax bill by post)A Simple Assessment is a tax bill HMRC works out for you, without you filing a return.P800P800 tax calculation letterA P800 is HMRC's tax calculation after the tax year ends.CIS registrationCIS registration confirmation letterWhen you register for the Construction Industry Scheme, HMRC confirms your payment status: net of deduction (20% taken by the contractor) or gross (no deduction, if you applied and qualify).CIS verificationCIS verification letter or reference from a contractorBefore paying a new subcontractor, a contractor must check with HMRC what rate to deduct: gross, standard (20%) or higher (30%).MTD letterMaking Tax Digital for Income Tax letterHMRC writes to say you need to use Making Tax Digital for Income Tax, or that it has signed you up.Tax return nudge"You may need to complete a tax return" letterHMRC sometimes writes to people when its records suggest they should be in Self Assessment, for example untaxed income or a high income child benefit charge.
At a glance

What to do, and by when

LetterBy when
Late filing penaltyPay a penalty within 30 days of the date on the penalty notice. File the return as soon as possible.
SA statementBy midnight on 31 January for the balancing payment and first payment on account, and 31 July for the second payment on account.
Payment reminder31 January and 31 July, midnight.
Notice to fileOnline 31 January after the end of the tax year; paper 31 October. New to Self Assessment? Register by 5 October.
Simple AssessmentIf the letter arrives before 31 October 2026 (for 2025/26), pay by 31 January 2027. If it arrives on or after 31 October 2026, pay within 3 months of the date of the letter. Contact HMRC within 60 days if it is wrong.
P800Follow the dates on your letter. Collecting by tax code starts the next 6 April.
CIS registrationRegister before your first CIS job so contractors deduct 20% instead of 30%.
CIS verificationAs soon as you see a 30% deduction. Each month at 30% costs you tax you may not need to pay.
MTD letterQuarterly updates are due 7 August, 7 November, 7 February and 7 May for those in MTD. Sign up before your start date.
Tax return nudgeRegister by 5 October after the end of the tax year, then file online by 31 January.

Frequently asked questions

Should I upload my HMRC letter to a website to have it explained?

No. Do not upload letters, photos or personal details to a site you are not sure of. This page explains each letter in general terms and asks for nothing.

How do I know if an HMRC letter is genuine?

Check it against the GOV.UK list of genuine HMRC letters. A genuine letter will not rush you, threaten you or ask you to transfer money. If in doubt, use your online HMRC account or find HMRC’s details on GOV.UK yourself.

What if I cannot find my letter here?

Check the GOV.UK list of genuine HMRC letters, which gives the letter code and what it asks you to do. If it is still unclear, contact HMRC or an accountant.

I got a letter saying I owe tax but I am not self-employed. Is it real?

It may be a P800 or a Simple Assessment, which HMRC sends to employees and pensioners. Check it against GOV.UK and the genuine letters list before you pay anything.

Why use this one

What is different about this guide

  • Each page gives the action and the deadline first, then the detail.
  • It links each letter to the calculator that works out the figure.
  • It is built from GOV.UK pages, and says where HMRC does not publish a letter code.
  • It leads with scam warnings, because scammers copy HMRC letters.
  • It runs without asking for your letter or any personal detail.
CalculatorPayments on Account CalculatorYour 31 January and 31 July payments, the balancing payment, and whether CIS means you owe none.CalculatorMaking Tax Digital CheckerDo you need MTD for Income Tax, and from when? Uses the £50k, £30k and £20k thresholds.CalculatorCIS Tax & Refund CalculatorCheck the CIS that should have been taken, spot deductions on materials, and estimate your refund or bill.CalculatorWhat's Changed for Me?Tick your situation and get your own list of every tax change and deadline for 2026/27 and 2027/28, with a £ estimate where we can work one out.GuideSelf Assessment deadlines and penaltiesEvery key date for 2025/26 and 2026/27, and exactly what it costs to file or pay late.GuideHow to claim a CIS refundStep-by-step for sole traders, with a worked example and the deadlines for 2025/26.

Sources and review

Last checked: 1 November 2026. The letter explanations, deadlines and scam advice on these pages. Written and checked by the HandySums team against the GOV.UK pages below. HandySums is independent and not an accountancy firm — see how we check our sums.

A guide, not tax advice. Explanations are a guide and HMRC has the final say. Always follow the dates and instructions on your own letter.