About Overpay or Invest
Overpay or Invest is a free calculator for people in the UK with a student loan. It helps you compare two choices: putting extra money towards your loan, or keeping to the minimum repayments and investing the difference instead.
Why it exists
For many UK borrowers, the loan is written off before it is fully repaid. When that is true, paying extra can just hand money to the loan company that would have been cancelled anyway. For others, the loan will be cleared and the interest really does cost money. Which case you are in depends on your plan, your salary and when you started repaying. The calculator works that out from your own numbers.
How it works
Each plan year you repay a fixed share of your income above your plan’s threshold, whatever your balance is. Whatever is left is written off a set number of years after the April you first started repaying. The calculator runs that year by year, once with minimum payments only and once with your overpayment, and compares the result with investing the same money at the return you choose.
- Covers Plan 1, Plan 2, Plan 4 (Scotland), Plan 5 and the Postgraduate Loan.
- Uses the 2026–27 thresholds and interest rates.
- Everything is calculated in your browser. The figures you type in are not sent to us. See the privacy policy.
Where the rules come from
Plan rules are taken from gov.uk and the House of Commons Library briefing on student loan repayment (CBP-10654). Thresholds and rates change, so please check your own figures against your loan statement.
Limits
It is an annual approximation of a monthly system, so it is directionally useful rather than exact to the penny. It models one loan at a time and assumes steady salary growth. Please read the disclaimer: this is general information, not financial advice.
Spotted a mistake?
If a threshold, rate or result looks wrong, please tell us at hello@overpayorinvest.com. Corrections are welcome and we will check them against official sources.
Who runs it
Overpay or Invest is an independent project run by an individual based in the United Kingdom. It is not affiliated with the Student Loans Company, the UK government or any lender.