Student loan: should you overpay?
UK student loans aren't like normal debt. You repay a fixed slice of income above a threshold, and anything left is written off after 25–40 years — so unless you'd clear the balance before then, voluntary overpayments are simply money you'd never have had to pay. This projects your loan and shows whether overpaying actually helps.
Your loan
The overpayment you're weighing up
With vs without overpaying
Worth knowing
A loan in name, a tax in behaviour
A UK student loan collects 9% of income above your plan's threshold, stops if income stops, and is wiped after 25 to 40 years depending on plan. No other debt behaves like this, which is why instincts trained on credit cards misfire so badly here. The only question that matters: on your earnings path, will you repay the balance before the write-off date? If the answer is no, the balance is a fiction and overpaying it is philanthropy aimed at the Student Loans Company.
The default example is a warning
Plan 2, £35,000 owed, £34,000 salary. Repayments run at £42 a month while interest accrues faster, and on these figures the loan is written off with £155,109 still outstanding. The balance nearly quintuples and it changes nothing: monthly repayments depend on salary alone, and the write-off erases the lot on schedule. A £5,000 lump sum thrown at this loan is £5,000 that would never have been repaid anyway. The calculator says so in red, and it's among the most valuable red messages on this site.
Who actually should overpay
The picture flips for borrowers who'll clear the loan comfortably before write-off: high earners, small balances, older Plan 1 loans with modest interest. For them the loan behaves like normal debt and early clearing saves real interest. The break-even depends on salary, salary growth, balance and plan, which is exactly what the tool models. Before committing money here, check the alternative uses: the debt or invest calculator for other debts and investments, and the take-home pay calculator to see what the 9% deduction actually does to your monthly pay while it lasts.
Common questions
Should I overpay my student loan?
Often no. UK student loans are repaid at 9% of income above a threshold and are written off after a set period, so many people never repay the full balance, which means voluntary overpayments can simply be lost. The calculator shows whether you are likely to clear it anyway.
When is a student loan written off?
It depends on the plan: Plan 2 is written off 30 years after you became liable to repay, Plan 5 after 40 years, and postgraduate loans after 30 years. If you will not clear the balance before then, overpaying rarely helps.
How much do I repay each year?
On Plans 1, 2, 4 and 5 you repay 9% of everything you earn above the threshold for your plan; postgraduate loans are 6%. The amount is based on your income, not on the size of the balance.
These results are estimates for general information only and are not financial advice. Check every figure yourself and seek appropriate advice from a qualified professional before making any decision. Read the full disclaimer.