UK Student Loans vs Investing Guide (Plan 2, Plan 5, Repay or Invest?)

UK Student Loan Types

The UK student loan system has several "plans" depending on when and where you studied. Plan 1 — for students who started university in England or Wales before September 2012 (and some earlier Scottish and Northern Irish loans). Interest rate is the lower of RPI or Bank of England base rate + 1%. Currently approximately 4.4%. Repayment threshold: £19,895. Written off after 25 years (or at age 65 for older loans). Plan 2 — for students who started between September 2012 and July 2023 in England. Interest rate is RPI (up to 4.1%) plus up to 3% depending on income (total up to 7.3% for high earners). Repayment threshold: £27,295. Written off after 30 years. This is the most common plan for current graduates. Plan 4 — for Scottish students (post-1998) and some older English/Welsh loans. Similar to Plan 1 but with a different threshold and (sometimes) a 30-year write-off. Postgraduate Loan — for master's or doctoral study. Interest rate is RPI + 3% (currently approximately 7.3%). Repayment threshold: £21,000. Repaid alongside any undergraduate loan at 6% of income above the threshold. Plan 5 — introduced for students starting from August 2023 in England. Interest rate is RPI (approximately 4.1%). Repayment threshold: £25,000. Repayment term: 30 years. Lower interest than Plan 2 but a lower repayment threshold means more graduates repay fully over their careers. This is the newest plan and its long-term implications are still being assessed. Investment priorities →

Interest Rates 2026

Student loan interest rates in 2026 are high by historic standards. The Retail Price Index (RPI) is approximately 4.1% in 2026. Under Plan 2, while you are studying and until the April after you graduate, interest is charged at RPI + 3%, making the rate approximately 7.3% for all borrowers. Once you start repaying, the rate varies by income — on earnings below £27,295, it is RPI only (4.1%); between £27,295 and £41,405, it gradually increases from RPI to RPI + 3%; above £41,405, it is RPI + 3% (7.3%). Plan 5 interest is simply RPI (approximately 4.1%) regardless of income — significantly lower than Plan 2 for higher earners. For comparison, best savings rates in 2026 are approximately 3–5% (Cash ISAs, easy-access accounts). Investment returns in a balanced portfolio are expected to be 5–7% nominally. The Plan 2 student loan interest rate of 7.3% for higher earners is higher than both savings and expected investment returns. This creates a strong mathematical case for overpayment — but only if you will actually repay the full loan over your career. For Plan 5 borrowers at 4.1%, the rate is much closer to savings rates and below expected investment returns, making overpayment less compelling. The interest rate alone does not tell the full story; the income-contingent repayment structure and eventual write-off mean a high interest rate does not necessarily mean you should rush to repay. Understanding investment returns →

Repayment Mechanics

Understanding how UK student loans work is essential before deciding whether to overpay. For Plan 2, you repay 9% of your income above £27,295. If you earn £40,000, your repayment is 9% of (£40,000 – £27,295) = 9% of £12,705 = £1,143 per year (£95 per month). Repayments are deducted from your salary by your employer (like tax and National Insurance) and you do not need to do anything. If your income falls below the threshold, repayments stop automatically. After 30 years, any outstanding balance is written off. This is critical: if you never earn enough to repay the full loan plus interest, you will never repay the full amount — the government writes it off. The interest accrues on the outstanding balance monthly. This means your balance can grow even while you are making repayments, a phenomenon known as "negative amortisation." A graduate with a £50,000 Plan 2 loan earning £35,000 may see their balance increase over time because the interest (7.3% while studying, then 4.1% when earning below the threshold) exceeds the repayments. For Plan 5, the mechanics are similar but with a lower threshold of £25,000 and interest capped at RPI (approximately 4.1%). The lower threshold means more graduates repay some of their loan, but the lower interest rate means the balance grows more slowly. The question of whether you will "fully repay" your loan before the write-off is the single most important factor in the repay vs invest decision. Financial priorities checklist →

Should You Overpay?

The decision to overpay your UK student loan depends on several factors. YES, consider overpaying if — you have a high-earning career with a clear trajectory (e.g., medicine, law, finance, technology) that means you will almost certainly repay the full loan plus significant interest over your career; your loan balance is relatively small and you expect to repay it fully within 10–15 years; you have a high Plan 2 loan and earn above £60,000+ with good prospects; you have already maxed out your ISA allowance and pension contributions and have no higher-interest debt. NO, do not overpay if — your career earnings are uncertain or you may take career breaks, meaning you may not repay the full loan before write-off; your loan balance is large (£60,000+) and your starting salary is moderate (£25,000–£40,000); you do not have a fully funded emergency fund; you have credit card debt or personal loan debt at higher interest rates; you have not yet started investing for retirement or using your ISA allowance. The key calculation: estimate your future earnings over the write-off period. If your loan balance is £45,000 and you earn £35,000, even with modest salary growth, you will likely not repay the full amount over 30 years. In this case, overpaying is throwing money away — the government will write off the remaining balance anyway. If you are a doctor earning £70,000 with a £55,000 loan, you will almost certainly repay in full, and the 7.3% interest makes overpayment an attractive "risk-free return." Most graduates fall into the "do not overpay" category. Start investing instead →

Investing While Having a Student Loan

For most UK graduates with student loans, investing is a better priority than overpaying. Here is the hierarchy of financial priorities. First, emergency fund — 3–6 months of essential expenses in cash comes before any loan overpayment or investing. Second, employer pension match — if your employer offers pension matching (most UK employers do via auto-enrolment), contribute enough to get the full match. This is free money. Third, high-interest debt — credit cards and personal loans at 15–30% interest should be repaid before considering student loan overpayment. Fourth, ISA investing — once your emergency fund is in place and you are getting the full pension match, invest inside a Stocks and Shares ISA. The £20,000 annual allowance should be used for long-term wealth building. Fifth, pension contributions — beyond the employer match, additional SIPP contributions provide tax relief at your marginal rate. For a higher-rate taxpayer, a £100 pension contribution costs just £60 (after 40% relief). The pension return (tax relief + investment growth) is difficult for student loan overpayment to beat. Sixth, student loan overpayment — only after the above priorities are met should you consider overpaying. The opportunity cost of overpaying is the investment returns you could have earned in an ISA or pension. Over 20–30 years, a 6% annual investment return inside a tax wrapper is almost certainly better than the 4–7% "savings" from student loan interest avoided — especially given the write-off protection. Investment priorities for graduates →

Plan 5 Special Considerations

Plan 5 (introduced for undergraduates from August 2023) has different economics that change the repay vs invest decision. Lower threshold — £25,000 vs £27,295 for Plan 2. This means more of your income is subject to repayment. A graduate earning £35,000 repays 9% of £10,000 = £900 per year under Plan 5, compared to 9% of £7,705 = £693 under Plan 2. This is approximately £207 more per year. Lower interest rate — RPI only (approximately 4.1%), regardless of income. This is significantly lower than the Plan 2 rate of up to 7.3% for high earners. The lower rate reduces the financial benefit of overpaying. 30-year write-off — the same as Plan 2, but the lower threshold means more graduates will repay fully. The Institute for Fiscal Studies estimates that approximately 60% of Plan 5 graduates will repay their loan in full, compared to approximately 35% for Plan 2. If you are on Plan 5 and expect to be a high earner, the case for overpaying is similar to Plan 2 but weaker due to the lower interest rate. If you are a middle earner (say £35,000–£50,000 lifetime average), you will repay more of your loan than under Plan 2 but may still benefit from the write-off. The lower interest rate means the "risk-free return" from overpaying is lower — 4.1% vs 7.3% for Plan 2. This makes investing more attractive relative to overpaying. For most Plan 5 graduates, the recommended priority is: emergency fund, pension match, ISA investing, then — only if your career earnings are very high — consider overpaying. Build your financial foundation first →

FAQs

Should I overpay my Plan 2 student loan if I have a high interest rate?

Only if you are confident you will fully repay the loan over your career. The 7.3% interest rate is high, but the write-off protects you if your career does not reach the level needed to repay. Use a student loan repayment calculator to estimate your lifetime repayments before deciding.

Is student loan debt considered "bad debt"?

Unlike credit card or personal loan debt, UK student loans are income-contingent and are written off after 30 years. They do not affect your credit rating in the same way as other debt. They are generally considered "good debt" or at least "neutral debt" because the repayments are manageable and there is a safety net.

Can I invest and pay off my student loan at the same time?

Yes, and this is the right approach for most people. Making the standard 9% repayments through your salary while simultaneously investing in an ISA or pension is mathematically optimal for most graduates, as it balances reducing your loan balance with building long-term wealth.

Does student loan debt affect my mortgage application?

Student loan repayments are taken into account when assessing affordability for a mortgage. The 9% deduction reduces your disposable income, which may reduce the amount you can borrow. However, it is treated less severely than other debt because it ends after 30 years or when repaid. Most lenders factor it in automatically.

What happens to my student loan if I move abroad?

You are still liable for repayments if your income exceeds the threshold (lowered to approximately £2,000–£3,000 for most countries). You must inform the Student Loans Company of your overseas address and provide evidence of income. Interest still accrues, and failure to report may result in penalties.