UK Student Loan trajectory.
Years to clear
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Annual repayment
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Total interest paid
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Your breakdown
Updates live as you type| Year | Interest added (7%) | Repaid | Balance |
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It behaves like a tax, not a loan
The biggest mental shift with a UK student loan is that it is nothing like a mortgage or a credit card. You repay a fixed percentage of income above a threshold, regardless of the balance, and anything left after the write-off period simply disappears. This calculator models that reality. You enter your balance, salary, plan type and interest rate, and it works out your annual repayment (9% of income above the threshold for Plans 1, 2, 4 and 5, or 6% for the Postgraduate Loan), then rolls the balance forward year by year adding interest, until either it clears or you hit the write-off horizon.
When interest outruns repayments
Run the defaults: a £45,000 balance, a £50,000 salary, Plan 2, and 7% interest. The threshold for Plan 2 is £27,295, so you repay 9% of the £22,705 above it, which is £2,043 a year. But 7% interest on £45,000 is £3,150 in the first year alone. Your repayment does not even cover the interest, so the balance grows rather than shrinks. The tool reports that the loan never clears within its 50-year window, and the running interest total balloons past half a million pounds. In real life that interest is academic, because Plan 2 is written off 30 years after you became liable to repay. You will pay the £2,043 a year for those 30 years and then the rest is cancelled, untouched.
The line slopes the wrong way. Far from falling, the balance creeps up every year. This is the crucial insight: for a typical Plan 2 graduate, the headline balance is a number you will mostly never repay, so chasing it down with overpayments can be throwing good money after a debt that was going to be written off anyway.
When overpaying does make sense
The picture flips for high earners. If your salary is large enough that the 9% repayments would clear the balance comfortably before the write-off date, then every pound of interest is real money you will actually pay, and voluntary overpayments save interest just like any other loan. The rough test is simple: if this calculator shows your loan clearing well before year 30, overpaying can pay off; if it shows the loan being written off, it almost never does. Plan 5 graduates face an even longer 40-year write-off, which makes early overpayment particularly hard to justify.
A note on plans and write-off dates
The write-off horizon depends on your plan. Plans 1, 2 and 4 and the Postgraduate Loan are generally written off 30 years after you first became liable to repay, while Plan 5, which applies to students starting courses from 2023, runs for 40 years. Repayments are collected through PAYE automatically if you are employed, or via Self Assessment if you are self-employed, so for most people the deduction happens without any action on their part.
Does my student loan affect my mortgage application?
Indirectly, yes. The 9% deduction reduces your net take-home pay, and lenders assess affordability on what actually reaches your bank account. A student loan does not appear on your credit file and is not treated as ordinary debt, but the monthly deduction does shrink the income a lender will lend against.
What happens to the loan if I move abroad?
You still owe it. If you leave the UK for more than three months you must tell the Student Loans Company, and they set repayments based on the income threshold for the country you move to. Stop responding and they can switch you to a fixed monthly repayment regardless of earnings, so it is worth keeping them updated.