Buy a property, or invest the money?
Compare buying a property with a mortgage against putting the same cash into investments — and see how leverage and an ISA change the answer.
The comparison
Wealth after the period
A deposit has two possible careers
£62,500 can be 25% of a £250,000 rental property, or it can go straight into the market. The property route earns rent and house-price growth on the full £250,000, courtesy of the mortgage, and pays for that leverage through interest, running costs, tax on the rent and the 5% stamp duty surcharge on the way in. The investment route grows unleveraged but frictionless, especially inside an ISA where returns arrive tax-free. On the defaults here, property finishes £90,730 ahead over 15 years. It earns that lead the hard way.
Leverage is the whole argument, tax is the counterargument
Modest growth on a mortgaged asset produces outsized returns on the cash invested, which is why property built so many fortunes. The counterweights have grown: Section 24 restricting interest relief for personal landlords, the stamp duty surcharge taking a bite before the first tenant, CGT waiting at the exit, while the ISA alternative compounds untouched by any of them. Run the same comparison with the taxable-account option and watch the gap change; the wrapper is doing more work than most people credit.
Price in the fourth dimension: effort
An index fund never rings on a Sunday about a leak. Property returns include payment for genuine work and risk, voids, tenants, regulation that tightens more often than it loosens. If the projected gap between the two routes is thin, the passive one usually deserves the verdict. Test the property leg deal-by-deal with the buy-to-let analyser and the market leg with the investment calculator, then decide which future self you want messages from.
Common questions
Is property or the stock market a better investment?
Property often looks better on paper because a mortgage lets you control a large asset with a small deposit, magnifying gains — but that leverage also magnifies losses, and property is illiquid and costly to trade. Investments, especially in a tax-free ISA, are cheaper, more liquid and diversified. The calculator weighs leverage, tax and costs on your own numbers.
How does leverage make property returns higher?
If you put down a £62,500 deposit on a £250,000 property, a 4% rise adds £10,000 — around 16% of your cash, not 4%. That gearing is the main reason buy-to-let can beat the market. The flip side is that a price fall hits your equity just as hard.
Does an ISA change the answer?
Often, yes. Investment growth inside an ISA is completely tax-free, while a buy-to-let owes Capital Gains Tax on the gain and income tax on the rent. Switching the investment side from taxable to an ISA can be enough to flip the verdict — toggle it in the calculator to see.
These results are estimates for general information only and are not financial advice. Property decisions have real consequences — check every figure and take appropriate professional advice before acting. Read the full disclaimer.