Pay Your Self Assessment Bill Through Your Tax Code: the £3,000 Limit and 30 December 2026
Written and reviewed by the AfterTaxSalary team · Updated for 2026/27 · Editorial standards · Methodology
How employees and pensioners can have a 2025/26 Self Assessment bill under £3,000 collected through their PAYE tax code: the three conditions, the 30 December 2026 online deadline, when HMRC will not do it, how to opt out, and a worked comparison with paying on 31 January 2027.
Quick answer (2025/26 tax return)
If you owe less than £3,000 for 2025/26, already pay tax through PAYE, and file your return online by 30 December 2026, HMRC collects the bill through your tax code automatically, in 12 equal monthly amounts with your usual tax1. Miss that date, or owe £3,000 or more, and the whole bill is due by 31 January 20272. You cannot part-pay to get under £3,0001.
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Who this guide helps
- Employees comparing calculator results with a payslip
- People checking why net pay changed without a salary change
- Job movers who need a clear baseline before comparing offers
What this guide covers
- Key facts
- When HMRC will not collect it through your code
- Worked example: £40,000 salary and £4,000 of rental profit
- Payments on account and bigger bills
- How this differs from a P800 or a K code
At-a-glance examples (2026/27)
Typical default outputs for quick context.
Key facts
- HMRC collects your Self Assessment bill through your tax code automatically if all three apply: you owe less than £3,000, you already pay tax through PAYE (for example as an employee or from a company pension), and you filed on time for this route1.
- For the 2025/26 return that means online by 30 December 2026. The paper deadline for this route was 31 October 202612.
- The tax is taken from your salary or pension in equal instalments over 12 months, along with your usual tax1.
- You cannot make a part payment to get the bill under £3,0001.
- If you would rather pay in one go, say so on your tax return1.
When HMRC will not collect it through your code
- You do not have enough PAYE income for HMRC to collect it1.
- You would pay more than 50% of your PAYE income in tax, or end up paying more than twice as much tax as you normally do1.
- You owed £3,000 or more and made a part payment to bring it under £3,0001.
- Self-employed Class 2 National Insurance, unless it has been due since before 6 April 20151.
If you do not qualify, the whole balance is due by 31 January 2027 and you pay it another way12.
Worked example: £40,000 salary and £4,000 of rental profit
Priya's salary is taxed through PAYE on 1257L. In 2025/26 she also made £4,000 profit from letting a flat, so she needs a return. The salary uses her Personal Allowance and her income stays in the basic-rate band, so the extra Income Tax is 20% of £4,000.
| Pay through tax code | Pay by 31 January 2027 | |
|---|---|---|
| Tax owed for 2025/26 | £800.00 | £800.00 |
| Return must be filed online by | 30 December 2026 | 31 January 2027 |
| How it is paid | 12 equal amounts of about £66.67 with her usual tax | One payment |
| Payments on account | None: bill under £1,000 | None: bill under £1,000 |
Her bill is under £1,000, so no payments on account are needed for 2026/273. If she had owed £3,200, coding out would not be possible even if she paid £300 early, so the full £3,200 would be due on 31 January 202712.
Payments on account and bigger bills
Payments on account are advance payments towards next year's bill, each usually half of the previous year's tax, due on 31 January and 31 July. You do not have to make them if your last bill was under £1,000, or if more than 80% of the tax you owed was paid outside Self Assessment, for example through PAYE3.
If you owe more than you can pay by 31 January 2027, you can set up a Self Assessment payment plan online if you owe £30,000 or less, your returns are up to date, and you have no other tax debts or HMRC payment plans. HMRC checks the plan is affordable4. Interest runs on anything paid late: 7.75% a year, the rate on GOV.UK when we checked on 3 November 2026; it moves with the Bank of England base rate5.
How this differs from a P800 or a K code
This route is for a Self Assessment balance you choose to clear through PAYE. If you are not in Self Assessment and HMRC finds you underpaid on your salary or pension, it sends a P800 tax calculation or a Simple Assessment instead, and an underpayment collected through your code can turn your code into a K code when the amount owed is larger than your allowances. See our P800, Simple Assessment and K code guides for those letters.
Related pages on this site
- Do employees need to do a tax return? The 2025/26 checklist
- P800 tax calculation: PAYE underpayments collected through your code
- K tax code: when the amount collected exceeds your allowances
- Simple Assessment: HMRC's bill when it cannot use your code
- Tax code 1257L: check the code after HMRC changes it
Use the calculator for practical scenarios
2026/27 factual reference points
Current tax-year thresholds used across this guide and calculator.
NI thresholds
- Primary threshold: £12,570
- Upper earnings limit: £50,270
- Rates: 8% then 2%
Student loan plans
- PLAN1: threshold £26,900, rate 9%
- PLAN2: threshold £29,385, rate 9%
- PLAN4: threshold £33,795, rate 9%
- PLAN5: threshold £25,000, rate 9%
- Postgraduate: threshold £21,000, rate 6%
Frequently asked questions
Can I pay my Self Assessment through my tax code?+
Yes, if you owe less than £3,000, you already pay tax through PAYE as an employee or pensioner, and you file online by 30 December (or on paper by 31 October). For the 2025/26 return the online date is 30 December 2026. HMRC then collects it automatically.
How is coded-out tax collected?+
In equal instalments over 12 months, taken from your salary or pension along with your usual tax deductions.
Can I pay part of my bill to get it under £3,000?+
No. GOV.UK says you cannot make a part payment to meet the £3,000 threshold; if you owed £3,000 or more, the full bill is paid another way by 31 January.
What if I do not want it taken through my tax code?+
Tell HMRC on your tax return that you do not want it collected that way, and pay the bill by 31 January 2027 instead.
Why can't HMRC collect my bill through my code?+
Common reasons: you do not have enough PAYE income, it would take more than 50% of your PAYE income, it would more than double your usual tax, you filed after 30 December online, or the bill is £3,000 or more.
Do I still need payments on account if I code out?+
They are not needed if your last bill was under £1,000 or more than 80% of your tax was paid outside Self Assessment, for example through PAYE.
Related guides
Sources & references
OfficialThe rates, thresholds and rules on this page are drawn from the official UK government sources below, using the confirmed 2026/27 figures. Each link opens the relevant HMRC or GOV.UK page in a new tab.
- Pay your Self Assessment tax bill: through your tax code — GOV.UK www.gov.uk/pay-self-assessment-tax-bill/through-your-tax-code
- Self Assessment tax returns: deadlines — GOV.UK www.gov.uk/self-assessment-tax-returns/deadlines
- Understand your Self Assessment tax bill: payments on account — GOV.UK www.gov.uk/understand-self-assessment-bill/payments-on-account
- Set up a Self Assessment payment plan — GOV.UK (HMRC online service) www.tax.service.gov.uk/pay-what-you-owe-in-instalments
- HMRC interest rates for late and early payments — GOV.UK www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates
Verified against published UK government guidance for 2026/27.
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