When does HMRC send a tax code change notice?
HMRC’s internal manual states that a P2 notice is issued when there is a change to a customer’s tax code. The notice follows the change, so the sequence matters more than the calendar. Two taxpayers can receive notices at different times of the year, or not at all in a given year, depending on whether and when their individual code changes.
| Situation | Result under the guidance |
|---|---|
| Your tax code changes | A P2 notice is issued |
| Your tax code does not change | No P2 notice is triggered by a code change |
| You look for a published send date | None exists on GOV.UK or in the internal manual |
Because no fixed date exists, a calendar cannot tell you when a notice will arrive.
What a tax code notice shows
A tax code notice is HMRC’s written record of the tax code it applies to your income. The sources set no fixed annual date, and a notice is not guaranteed every year.
When reading a notice, check these elements:
- The code figure: the full code, including its numeric and letter parts.
- The tax year covered: confirm that the notice applies to the year you are looking at.
- Any explanation given: if the notice explains why the code changed, compare it with your circumstances.
The code combines numbers and letters. Use HMRC’s own explanation on the notice or on GOV.UK to interpret each part, rather than relying on memory or a third-party summary.
Add them once a dated official source is supplied.*
Why can your tax code change mid-year?
Your tax code is a set of figures that tells your employer or pension provider how much Income Tax to deduct from each payment. It is set for the tax year, but HMRC recalculates it when something changes the figures behind it. Three kinds of mid-year event commonly produce that change.
Starting or leaving an employment or a new pension
- Starting a job: HMRC needs to know which income is now taxed through that employer and whether you have other taxable income that should be reflected in your code.
- Leaving a job: earnings and deductions linked to that employment stop counting toward your code, and the code can be recalculated for the income that remains.
- A new pension: once a second source of taxable pension income starts, the code can change to account for it.
Each event can move the code up or down, depending on which income remains taxed through it.
Benefits in kind and untaxed income added to the code
Some income is not paid as cash through payroll, or is not taxed at source. This includes certain benefits in kind (non-cash perks provided through your employment) and other income that has not been taxed. When HMRC identifies such amounts, they are typically added to your code, so the tax due on them is collected through regular deductions from pay or pension. The effect is usually a lower tax-free allowance in the code and therefore more tax deducted from each payment. The amount added reflects the value of the benefit or income, so the new code will differ from the one you had before.
Corrections for past over- or underpaid tax
If tax was over- or underpaid in an earlier period, the difference can be settled through your code. An underpayment is generally recovered by adjusting the code so that a further amount is deducted from future payments. An overpayment can lead to a code that gives you more allowance, returning money through lower deductions. In both cases, the change applies to the payments that follow the adjustment, not to earlier pay already received.
How can you check your tax code?
GOV.UK (HMRC, 2026) lists four ways to see your current tax code: online, in the HMRC app, on your payslip, or on a Tax Code Notice letter.
Online account
Sign in to your HMRC online account to see your current code. Sign-in is required, so have your login details ready before you start. Once signed in, you can also open the codes for previous years. Checking several years side by side shows whether your code has changed between tax years. Your online account lets you view previous years’ codes, so use it if you want to compare codes over time.
HMRC app
The HMRC app is an alternative to the website. Use it if you prefer your phone to a computer. Sign in with the same details you use for the online account, then find your current code in the app. The source does not state whether the app shows previous years, so check the app’s own screens if you need older codes.
Your payslip
The tax code is printed on your payslip. Open the payslip for the pay period you want to check and read the code shown. A payslip reflects the code applied to that pay, so it tells you the code in use at that point, not a history.
Tax Code Notice letter
HMRC may send a Tax Code Notice letter that states your code. Keep it with your other tax paperwork, as it provides a dated written record of the code HMRC has set for you.
What if you receive no notice?
No notice does not mean your tax code is correct or unchanged. A change can take effect without a notice you can see.
Your existing code stays in force until it is replaced. Until HMRC issues a new code, the one you already have continues to apply to your pay. If that code is out of date, it keeps applying without any new message to alert you.
The main consequence is an unexpected deduction. If your tax code has changed and you were not notified, the first sign may be a difference in the tax deducted from your pay. A difference in the tax deducted without any notice is a reason to check your code against your payslip and your online account, and to contact HMRC if it looks wrong.
Two things can be true at once: no notice has arrived, and your code is wrong.
Do you get an email or a letter?
If you sign up for paperless notifications, HMRC emails you when your tax code changes. You may also get a Tax Code Notice letter. There are two possible routes: an email notification and a printed Tax Code Notice letter. Which one you receive depends on your delivery settings, and you may receive both.
If you have signed up for paperless notifications, HMRC emails you when your tax code changes, so email is the channel to expect once you have opted in. GOV.UK also states that you may still get a Tax Code Notice letter, so paperless sign-up does not guarantee that no paper notice will arrive.
The table below compares the two channels.
| Channel | How it reaches you | Where to act on it |
|---|---|---|
| Email notification | Sent when you have signed up for paperless notifications | Check the inbox linked to your HMRC account |
| Tax Code Notice letter | Sent by post; you may get one in addition to any email | Keep the letter and compare the code with your records |
To switch between email and post, change your delivery preferences in your online account with HMRC. The source material available for this section does not give the exact menu path or wording, so follow the current instructions on GOV.UK rather than relying on a remembered screen. Changing the preference affects future notices; it does not replace notices already issued.
What should you do if your code looks wrong?
If your tax code seems incorrect, work through the steps in order. Start with your own records, then contact HMRC only once you have the information they will ask for.
| Step | Action | What you need |
|---|---|---|
| 1 | Gather your evidence | Recent payslips and any Tax Code Notice letter you received |
| 2 | Compare the code on each document | The code on your notice, your payslip and your current record |
| 3 | Contact HMRC to query the code and ask for a review | Your payslips, notice details and any information about income or benefits you think is missing |
| 4 | Check the corrected code | The revised notice or updated code from HMRC |
Your payslips and the notice show the code HMRC is applying and the pay it has been applied to, so you can tell HMRC exactly which figure you dispute. If the code on your payslip differs from the code on the notice, note both, because the difference itself is the point to raise.
When you contact HMRC, state which code you believe is wrong and why. Ask them to review it and explain how the code was calculated. Keep a record of the date, the person you spoke to and any reference they give you.
If the review shows you paid too much tax while the code was wrong, ask HMRC whether and how any overpayment will be repaid. The outcome depends on HMRC’s assessment of your case. If you disagree with HMRC’s answer, you can seek independent advice, for example from a tax adviser or Citizens Advice.
Frequently asked questions
Will I receive a tax code change notice every year?
No. GOV.UK sets no fixed timetable, so a notice only follows when your tax code actually changes. Check your code if you expect a change, rather than waiting for a yearly letter.
Where can I check my tax code without waiting for a letter?
You can view it online after signing in to your HMRC account, where previous years are also available. It also appears in the HMRC app and on your payslip.
Does signing up for paperless notifications change how I hear about a code change?
Yes, it changes the channel. With paperless notifications, HMRC emails you when your code changes, though you may still receive a Tax Code Notice letter.
