Student Loan Repayment Calculator — PAYE, Self Assessment & Write-Off

PAYE only ever sees your salary — Self Assessment sees everything. If you have a student loan and also file a Self Assessment return, because you're a landlord, self-employed, or both, your employer's payroll deducts 9 per cent (6 per cent for a Postgraduate Loan) of salary above the plan threshold each pay period, with no idea what else you earn. HMRC then reworks the whole year's liability on Self Assessment using your combined income, and collects any shortfall by 31 January alongside the rest of your tax bill. This calculator does both sums side by side, projects how many years it would take to clear the balance at the current interest rate, and shows the write-off date for the plan you're on.

The five plans, threshold and rate

Each plan has its own annual repayment threshold and rate for 2026/27, verified on gov.uk:

• Plan 1: repay 9 per cent of income above £26,900 a year.
• Plan 2: repay 9 per cent of income above £29,385 a year.
• Plan 4 (Scotland): repay 9 per cent of income above £33,795 a year.
• Plan 5: repay 9 per cent of income above £25,000 a year.
• Postgraduate Loan: repay 6 per cent of income above £21,000 a year.

The £2,000 rule for rental and self-employment income

HMRC's own Self Assessment manual is explicit about how other income is treated: unearned income — which covers rental profit as well as most self-employment profit for this purpose — “is only taken into account in computing liability to Student/Postgraduate Loan repayments if the total amount of unearned income exceeds £2,000”. That is a cliff edge, not a slice taken off the top: a landlord with £1,800 of rental profit has none of it counted; a landlord with £2,100 has the whole £2,100 counted alongside their salary. Once combined income clears the plan threshold, the 9 per cent (or 6 per cent) rate applies to the amount above it, calculated on the year as a whole.

PAYE now, Self Assessment later

Because payroll only ever deducts against salary, anyone with meaningful rental or self-employment profit on top almost always owes something extra through Self Assessment — the amount HMRC calculates on combined income, less whatever was already taken through PAYE. That extra is due by 31 January with the rest of the Self Assessment bill; see the Self Assessment deadlines page for the full calendar, and the payments on account calculator if the total pushes you into paying twice a year in advance.

Interest, years to clear, and write-off

Plan 1, Plan 4 and Plan 5 currently charge a single fixed rate of 4.1 per cent; the Postgraduate Loan charges 6 per cent. Plan 2 is different: it is RPI-linked and tiers by income, from 4.1 per cent at or below £29,385 up to 6 per cent at or above £52,884, with a straight-line taper in between — so two Plan 2 borrowers on the same balance can be charged different rates depending on what they earn. Enter a current balance and this calculator projects, year by year, how long it would take to clear at today's income and rate — a simple projection that assumes both stay still, which real life rarely does. Compare that against the write-off date: 25 years after the April you first became due to repay on Plan 1, 30 years on Plan 2, Plan 4 or the Postgraduate Loan, and 40 years on Plan 5.

Does overpaying make sense?

Only if the loan is on track to be repaid in full before the write-off date — overpay a loan that would have been written off anyway and the extra money simply repays a debt the government would otherwise have cancelled. If the projection above clears the balance well before write-off, extra payments reduce the total interest paid; if write-off looks likely to arrive first, they don't. This is general information, not financial advice — a decision like this should weigh other borrowing, savings and pension priorities too.

Plan thresholds and repayment rates: GOV.UK — Rates and thresholds for employers 2026 to 2027 and Income Tax rates and Personal Allowances, read 12 September 2026 (imported unchanged from this site's take-home pay calculator). Interest rates: GOV.UK — Repaying your student loan: what you pay, read 13 September 2026 — rates change periodically; check the same page for the current figure. Write-off dates: GOV.UK — when your student loan gets written off or cancelled, read 13 September 2026. Other income via Self Assessment: HMRC Self Assessment Manual, SAM121610 and GOV.UK — repaying your student loan if you're self-employed, both read 13 September 2026. General information, not advice.