How repayments are calculated
You repay a percentage of income above the threshold for your plan, not a percentage of the amount still outstanding. Official guidance is that the amount you owe has no impact on how much you repay each year. Plans 1, 2, 4 and 5 repay at 9%. A Postgraduate Loan repays at 6%. If you have a Postgraduate Loan and an undergraduate plan, the two percentages can apply together, which is what the optional checkbox does.
Thresholds change by tax year. For 2026/27 the official employer rates page lists Plan 1 at £26,900, Plan 2 at £29,385, Plan 4 at £33,795, Plan 5 at £25,000 and the Postgraduate Loan at £21,000. For 2025/26 the official employer rates page lists Plan 1 at £26,065, Plan 2 at £28,470, Plan 4 at £32,745 and the Postgraduate Loan at £21,000. It does not list a Plan 5 threshold for 2025/26, so this tool will not invent one: if you pick Plan 5 and 2025/26, you will see that limitation instead of an estimate.
On the current “how much you repay” page, a Plan 1 example with £33,000 of income and the £26,900 threshold produces a 9% repayment on the £6,100 excess, which is £549 for the year. That is the same arithmetic this calculator uses for 2026/27 Plan 1.
Self Assessment and PAYE
If you are employed only, repayments are usually taken through PAYE when a job is above the weekly or monthly threshold. If you are self-employed, or you complete a Self Assessment return for another reason, HMRC works out how much you repay from the return, based on income for the whole year. If you are both employed and self-employed, the official method uses combined income for the year, then deducts any repayments already taken from a salary.
This estimator uses a single income box and does not try to reconstruct a PAYE-versus-Self-Assessment split, refunds where annual income ends below the yearly threshold, or overseas repayment terms. Interest on the loan is also outside this tool. It is a repayment estimate, not a balance, and not a figure from the Student Loans Company.
Student loan repayments are not included in payments on account; they are collected on the 31 January balancing payment if they are due through Self Assessment. You still file the return, if you need one, for free on GOV.UK.
If you do not know which plan you are on, check your Student Loans Company account or the starter information you gave an employer, rather than guessing. A Plan 1 threshold and a Plan 2 threshold are several thousand pounds apart in both official years, so the same income can produce a repayment on one plan and nothing on the other. Overseas repayment terms, and interest added to the outstanding balance, are outside this estimator.