UK student loans share a name with bank loans and almost nothing else. Understanding the difference changes decisions about repayment, overpayment and even whether the balance matters at all.
The Mechanics
You repay 9% of income above your plan’s threshold — nothing below it. Plan 2 (2012–2022 starters): threshold ~£29,385, written off after 30 years. Plan 5 (2023+): lower threshold ~£25,000, but a 40-year write-off. Repayments stop when income stops; the balance never appears on credit files; mortgage lenders see only the monthly deduction.
Why the Balance Is (Mostly) Irrelevant
On Plan 2, government forecasts have long expected the majority of graduates never to clear the balance before write-off. For them, the "debt" is functionally a 9% additional tax for 30 years — and whether they owe £45,000 or £60,000 changes their monthly payment by precisely nothing.
When Overpaying Is a Mistake
Voluntarily overpaying a balance destined for write-off is donating money to the Treasury. Overpaying only pays off for those who will clear it anyway: consistently high earners with modest balances. Everyone else does better directing spare cash at pensions (with tax relief) or a mortgage deposit.
The Interaction Nobody Mentions
The 9% stacks on top of tax and NI: a Plan 2 graduate earning between £50,270 and £60,000 faces a marginal deduction of 51% (40 + 2 + 9). Salary-sacrifice pension contributions reduce loan repayments too — one of the quieter arguments for them.