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Payments on account calculator: what you pay on 31 January 2027

Your January tax bill is often bigger than you expect: it is the rest of your 2025/26 tax plus a first advance payment towards 2026/27. Put in the figure from your tax return to see exactly what is due on 31 January and 31 July 2027, and how much to save each month until then.

Checked for 2026/27 — for the 2025/26 bill due on 31 January 2027 and the 2026/27 payments on account, last reviewed 29 October 2026.

Your figures

The total income tax and Class 4 National Insurance on your 2025/26 return, after any tax already taken through PAYE. Leave out student loan, Class 2 NI and capital gains tax: put those in “Other amounts” below.

From the tax calculation on your 2025/26 return. Not filed yet? Estimate it with the self-employed tax calculator (2025/26 bands are the same).

What you paid on 31 January 2026 and 31 July 2026. Leave blank if this is your first tax return.

These are paid with your January bill but are not used to work out payments on account.

Student loan, voluntary Class 2 NI or capital gains tax for 2025/26.

From your P60. Used for the 80% rule and to check if you can pay through your tax code.

Your best estimate of 2026/27 income tax and Class 4 NI. If you reduce your payments on account and the real bill is higher, HMRC charges interest on the difference.

If your income has dropped, you can ask HMRC to lower your payments on account.

What you pay

Pay by 31 January 2027

£0

Rest of your 2025/26 billYour 2025/26 bill plus any other amounts, minus the payments on account you already made. This is the “balancing payment”.
£0.00
First payment on account for 2026/27Half of your 2025/26 income tax and Class 4 NI, paid in advance towards 2026/27.
£0.00
Total due 31 January 2027
£0.00
Second payment on account, 31 July 2027
£0.00
Save each month until JanuaryThe January total spread over the months left until 31 January 2027.
£0.00

Paid too much:

Pay through your tax code:

Can't pay it all?

Paying late:

Your next two tax payments

Results update as you type. No sign-up, and nothing you enter leaves your device.

Worked example

Priya started as a self-employed florist in 2025. Her profit for 2025/26 was £30,000 and this is her first tax return. Her bill is £3,486 income tax (£17,430 × 20%) plus £1,045.80 Class 4 NI (£17,430 × 6%).

2025/26 income tax + Class 4 NI£4,531.80
Less payments on account already made£0.00
Rest of the 2025/26 bill£4,531.80
First payment on account for 2026/27 (half of £4,531.80)£2,265.90
Due 31 January 2027£6,797.70
Second payment on account, due 31 July 2027£2,265.90
Total over the two dates£9,063.60

That is twice her yearly bill within six months, which is why the first January catches so many people out. From 29 October 2026 she would need to put aside about £2,265.90 a month to have the January figure ready. Next year, the £4,531.80 she pays on account comes off her 2026/27 bill, so January 2028 should be much smaller if her profit stays the same.

How it works, in plain English

On 31 January 2027 you file your 2025/26 return and pay what is left of the 2025/26 bill (the balancing payment). If you have to make payments on account, you also pay the first half of an advance towards 2026/27 on the same day, and the second half on 31 July 2027.

Who has to make payments on account

Everyone in Self Assessment does, unless last year's bill was less than £1,000, or more than 80% of your tax was taken at source, for example through PAYE on a job. Each payment is half of the income tax and Class 4 National Insurance on your last return. Student loan, Class 2 and capital gains tax are not included.

If your income has dropped

You can ask HMRC to reduce them: sign in to your online account, view your latest return and choose “Reduce payments on account”, or send form SA303. Only do this if you are confident, as HMRC charges interest if the real bill turns out higher.

If you cannot pay it all

If you owe less than £3,000, already pay tax through PAYE and file online by 30 December 2026, HMRC can collect the balance through your tax code instead. Otherwise, once you have filed, you can set up a payment plan online for bills up to £30,000. File on time either way: missing the deadline adds a £100 penalty even if you owe nothing.

If you pay late

For the 2025/26 bill, HMRC adds 5% of the balancing payment still unpaid after 30 days, and again at 6 and 12 months. Interest at 7.75% a year (Bank of England base rate plus 4%) runs on everything paid late, including payments on account. Full details are on GOV.UK.

Frequently asked questions

Why is my first January tax bill so big?

In your first year of Self Assessment, HMRC asks for the whole year's bill plus a first payment on account towards the next year, which is half as much again. So a £4,000 bill becomes £6,000 on 31 January and another £2,000 on 31 July. From the second year the payments on account you have already made come off the bill, so it evens out.

Do I have to make payments on account?

Yes, unless your last Self Assessment bill was less than £1,000, or more than 80% of your tax was already taken at source, for example through PAYE on a job or pension. Each payment is half of the income tax and Class 4 National Insurance on your last return.

What is not included in payments on account?

Student loan and postgraduate loan repayments, voluntary Class 2 National Insurance and capital gains tax are paid with your January bill but are not used to work out payments on account. Put them in the 'other amounts' box so the January total is right.

Can I reduce my payments on account?

Yes, if you expect your 2026/27 bill to be lower, for example because your income has dropped. Sign in to your HMRC online account, view your latest return and choose 'Reduce payments on account', or send form SA303. If you reduce them too far you pay interest on the shortfall.

What happens if I cannot pay by 31 January 2027?

File your return on time anyway, so you avoid the £100 late filing penalty. If you owe £30,000 or less you can set up a payment plan online after filing. A plan agreed before the 30-day point stops the 5% late payment penalty, but interest is still charged.

Do late payment penalties apply to payments on account?

For the 2025/26 bill, the 5% late payment penalties are charged on the balancing payment, not on payments on account. Interest, currently 7.75% a year, is charged on any late amount, including payments on account.

Estimates only, not tax advice. These figures are a guide based on the information you enter and the rules for the 31 January 2027 bill. Your own position can differ — check GOV.UK or an accountant before relying on them.