Comparison · Borrowing · 2026
Repay Student Loan Early vs Invest 2026: Which Is Smarter?
A UK student loan is unlike any other debt. You repay 9% of income above a threshold, repayments pause if your income drops, and whatever is left is written off after 30 or 40 years. That makes the usual instinct to clear debt early surprisingly often the wrong move. This 2026/27 comparison explains how Plan 2 and Plan 5 work, why most graduates never repay the full balance, and uses worked examples to show when overpaying beats investing the same money in a pension or ISA - and when it does not.
TL;DR - 30-Second Summary
- - Most graduates: investing wins - the loan is likely written off anyway
- - Repayment: only 9% of income above the threshold, never more
- - Write-off: Plan 2 after 30 years, Plan 5 after 40 years
- - Repay early only if: you are a high earner certain to clear the balance
How the Loan Works
| Feature | Plan 2 | Plan 5 |
|---|---|---|
| Repayment threshold | £29,385 | £25,000 |
| Repayment rate | 9% above threshold | 9% above threshold |
| Written off after | 30 years | 40 years |
| Repays if income falls | No - pauses below threshold | No - pauses below threshold |
| Affects credit score | No | No |
Worked Example: £5,000 Spare
A Plan 2 graduate earning £35,000 has £5,000 spare. They repay 9% of income above £29,385, which is about £505 a year regardless of what they do with the £5,000. Compare overpaying the loan with investing the money.
| Option | Immediate effect | Likely outcome |
|---|---|---|
| Overpay £5,000 on the loan | Monthly repayment unchanged | No saving if loan is written off anyway |
| £5,000 into a pension (higher rate) | Grossed up to ~£8,333 | Tax relief plus decades of growth |
| £5,000 into a Stocks & Shares ISA | Invested tax-free | Accessible growth, no tax on returns |
The key insight is that the monthly repayment does not change when you overpay - it is fixed at 9% of income above the threshold. If this graduate will not clear the loan before write-off, the £5,000 overpayment buys nothing, whereas in a pension it is boosted by tax relief and grows for decades. Compare paths with the student loan calculator and the compound interest calculator.
When Overpaying Does Make Sense
For a high earner the maths can flip. Someone earning well into six figures will repay the full balance long before the write-off date, so every pound of interest is real money they will actually pay. For them, clearing the loan early cuts the total interest and can be worthwhile, particularly if expected investment returns are modest and certain.
Even then, the order of priorities matters. Capturing an employer pension match, clearing expensive credit card debt, and building an emergency fund all usually come before overpaying a student loan, because each offers a clearer and often larger return.
Who Should Choose What
- - You are on a modest or variable income
- - You are unlikely to clear the loan before write-off
- - You have unused pension or ISA allowance
- - You want accessible, growing savings
- - You are a high earner certain to clear the loan
- - You will repay well before the write-off date
- - You strongly dislike carrying any debt
- - You have already invested and built reserves
Verdict
For the majority of graduates, a UK student loan behaves more like a temporary graduate tax than a conventional debt, and the smart move is to invest spare money rather than overpay. Pension tax relief and tax-free ISA growth generally do far more for your wealth than reducing a balance that may be written off anyway. The exception is high earners who will comfortably clear the loan before its write-off date, for whom overpaying genuinely saves interest. Check which plan you are on, estimate whether you are likely to clear the balance, and only then decide.