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Most UK student loan borrowers never clear their balance before it's automatically written off — which changes the maths on overpaying completely. Enter your numbers below for an instant, plan-specific answer.
This is a simplified estimate for education purposes, not regulated financial advice. It assumes your salary grows at the selected rate for ten years, then in line with prices, and your loan's interest rate stays flat at today's figure — the real SLC calculation compounds monthly, and if you're on Plan 2, your rate will actually track your income up or down as it changes over time rather than staying fixed. If you have more than one loan (e.g. an undergraduate plan plus a Postgraduate Loan running alongside it), this only models one at a time. Candid Personal Finance Ltd is not authorised or regulated by the Financial Conduct Authority (FCA).
The plan you're on determines your interest rate, your repayment threshold, and — critically — how long until any remaining balance is wiped clean regardless of what you've repaid.
| Plan | Interest rate | Repay above | Repayment rate | Written off after |
|---|---|---|---|---|
| Plan 1 (pre-2012 / NI) | 4.1% | £26,900/yr | 9% | 25 years |
| Plan 2 (2012–2023 starters) | 4.1%–6%, ramped by income | £29,385/yr | 9% | 30 years |
| Plan 4 (Scotland) | 4.1% | £33,795/yr | 9% | 30 years |
| Plan 5 (2023 onwards) | 4.1% | £25,000/yr | 9% | 40 years |
| Postgraduate Loan | 6% | £21,000/yr | 6% | 30 years |
Plan 2's rate isn't a single figure — it ramps linearly from RPI (4.1%) towards RPI+3% as your income rises from £29,385 to £52,885, and it's a straight-line scale, not a step. Below £29,385 you pay 4.1%. The rate is currently capped at 6%, which the scale reaches at an income of about £44,270, so everyone above that pays 6%. The rates in this table apply from 1 September 2026 to 31 August 2027. Rates and thresholds are reviewed annually — check gov.uk for the current year if you're close to a decision. If you know your exact rate, enter it above to override the plan default.
If your projected balance is heading to zero at write-off anyway — because your income growth is outpacing interest — then overpaying genuinely saves you money: it clears the loan sooner and cuts the interest you'd otherwise pay.
But if your balance is stable or growing (interest is outpacing your repayments), the loan is on track to be forgiven regardless of what you do. In that case, every extra pound you put toward it just reduces the amount that gets written off — it isn't "saved," because you were never going to pay it anyway. Worse, if overpaying is enough to tip you from "written off" into "cleared in full," you've actually turned free debt forgiveness into a debt you paid for entirely yourself.
Overpaying is worth it when you're already on track to clear the loan before write-off — in that case it's simply cheap, guaranteed debt reduction. The calculator above checks exactly that, using your salary, plan, balance and your chosen salary growth projection.
The £100,000 tax trap calculator — if you're earning near £100k, pension sacrifice there often beats both overpaying your loan and holding cash. · Mortgage overpayment vs high-yield savings — the same "clear debt vs hold cash" question, for a mortgage fix instead of a student loan.