Payments on account calculator

See what Self Assessment will ask for on 31 January 2027 and 31 July 2027, based on your 2025–26 bill.

Your 2025–26 Self Assessment bill (income tax and Class 4 National Insurance, after tax taken at source) Payments on account you already made for 2025–26 (0 if this is your first year) 80% or more of my total tax was already taken at source (for example through PAYE)

How it works

If your Self Assessment bill is over £1,000, HMRC usually asks for advance payments towards next year's bill: two payments on account, each half of this year's bill.
They're due on 31 January and 31 July. 31 January also brings any balancing payment for the year just ended.
No payments on account are needed if the bill is £1,000 or less, or if 80% or more of your tax was already taken at source.
In your first year, January can be the whole bill plus half of next year's: about 150% of what you expected.
If you know next year's income will be lower, you can ask HMRC to reduce your payments on account.

General information, not tax advice. Your real figures are on your Self Assessment account. See GOV.UK: payments on account.

Set money aside as you go. The Self Assessment Tracker (£12) adds up income and expenses through the year so January isn't a surprise. The Budget and Savings Planner is pay what you want.