Overpay vs invest?
You've got spare cash. The same £300/mo can clear your mortgage early, or compound in an ISA / pension / GIA. We model both paths over your full mortgage term, apply UK tax to the investment side, and tell you the £-denominated winner.
Overpay your mortgage, or invest the cash?
We compare both strategies over your full mortgage term, with UK tax on the investment side.
Invest — you're £40,979 ahead
Your expected 7% return beats the 4.79% interest you'd save by overpaying — even after vehicle tax. The market is risky; this answer is an expectation, not a guarantee.
Investment portfolio value, gross, in each strategy. Mortgage equity is identical at term end so it cancels out.
The agent factors in tax, deal end, and risk.
Pension reliefs, employer matches, ISA allowances, fund choice — the agent walks through them with your numbers.
How we compare them
Overpay path: you pay your normal monthly + the spare cash every month until the mortgage clears (typically years early). From the early payoff date through to the original term end, we redirect that plus your old monthly payment into the same investment vehicle. So both paths invest the same money; the question is just when.
Invest path: you keep your mortgage on schedule and invest the spare cash from month one. Over a long term, that extra time in the market compounds.
Tax matters. ISA returns are tax-free. GIA gains above £3,000 a year incur Capital Gains Tax (18% basic / 24% higher for non-property assets). Pensions get income-tax relief at the front (so £100 of net cash becomes £125+ in the pension), and 25% comes out tax-free at retirement with the rest taxed at your marginal rate. We model all three.
Risk warning. Overpaying is a guaranteed return equal to your mortgage rate. Investing has an expected return — markets can fall. The verdict here is "expected" not "guaranteed". For a personalised view that factors in your time horizon and risk tolerance, hand off to the AI agent.
Estimates only — not regulated financial advice. Pension funds are illiquid until age 55+ (rising to 57 from April 2028). Tax rules change; figures based on FY2025-26 UK rules.