Payments on Account Calculator: What You Owe on 31 January and 31 July
What you pay on 31 January and 31 July: balancing payment plus the two 50% instalments, the £1,000 and 80%-at-source exemptions, and whether to reduce them.
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The January bill that catches new landlords is not one year’s tax — it is one and a half. Once your Self Assessment bill passes £1,000, HMRC asks for next year’s tax in advance: two payments on account, each half of this year’s bill, due 31 January and 31 July. The first one lands on the same day as the balancing payment for the year just finished. This calculator lays out the exact cash on each date and tells you whether you are exempt.
The two exemptions
- Small bill: if the tax you owe through Self Assessment is under £1,000, there are no payments on account.
- Mostly taxed at source: if more than 80% of the year’s tax was collected outside Self Assessment — through your PAYE tax code, for example — there are none either. Employed landlords with a small rental profit often fall here.
Where the numbers come from
Each payment on account is half of the tax owed through Self Assessment for the year just filed (income tax plus Class 4 National Insurance for the self-employed; Capital Gains Tax and student loan repayments are not included). The 31 January figure is the balancing payment for the year just finished — this year’s tax minus any payments on account you already made towards it — plus the first instalment for the year ahead. If you overpaid, the excess offsets the first instalment.
Reducing payments on account
If you know next year’s tax will be lower — a property sold, a mortgage rate up, a job change — you can ask HMRC to reduce the instalments (form SA303, or online). Reduce them below what turns out to be due and HMRC charges interest on the shortfall, so cut to a realistic estimate, not to zero. Our payments on account guide quotes the gov.uk rules in full; the rental income tax calculator gives you the bill to feed in.
Rules per gov.uk’s “Understand your Self Assessment tax bill” (checked 5 Sep 2026). Thresholds from the same data file as our other calculators. General information, not advice.
Asked constantly
Because it usually includes 150% of one year's tax: the full amount for the year just filed plus the first 50% payment on account for the year ahead. The second 50% follows on 31 July.
Yes — they apply to anyone whose Self Assessment tax is £1,000 or more and not mostly collected at source. Rental income is not taxed at source, so most landlords with a meaningful profit make them.
The overpayment is set against your next bill or refunded. The calculator shows an overpaid figure against the first instalment when your payments exceeded the tax due.
You can ask, but if the real bill turns out higher than your reduced payments, interest runs on the difference from the original due dates. Reduce to an honest estimate instead.
Doing this every quarter, not just once?
Keep the same figures all year instead of re-typing them: rent and expenses per property, the Section 24 finance costs and the MTD quarterly totals, in one workbook.
Landlord Tax Lab stays free. We also sell the Landlord Tax Pack: one Excel workbook for up to 10 properties that logs rent and expenses per property, maps every line to its SA105 box, keeps Section 24 finance costs out of the expense boxes, and rolls up the MTD quarterly totals. £19 once — no subscription.
Disclosure: we make and sell the Tax Pack — this is our own product, not a paid recommendation. It does not file anything with HMRC and it is not tax advice; filing goes through you, your accountant or software on HMRC’s compatible-software list.
Sources
The primary documents this page is built from. Links checked 5 September 2026.