Cash vs mortgage calculator, in hindsight

What if I'd taken a mortgage instead of buying with cash?

Pick the year you bought. This replays real mortgage rates and stock market returns, paying cash or borrowing and investing the rest, to the latest month.

Where
The cash not spent went into
Year you bought
Your numbers

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%avg

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What you'd have minus what you'd owe, on each path. Below zero means the mortgage is bigger than the investments. Touch the chart to scrub.

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How it played out

Where the money went

Both buy the same home and spend the same each month. Paying cash invests what the mortgage would have cost.

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Assumptions you can change

How this cash vs mortgage calculator works

This cash vs mortgage calculator replays the choice a cash buyer faces: pay for a home outright, or take a mortgage and invest the money that isn't spent. Pick the UK or the US, the year you bought (any January from 2000), and a deposit from 5% to 75%, and it runs month by month to the latest data.

Both paths buy the same home and spend the same each month. Paying cash uses all the money on the day, then invests every month what the mortgage payment would have been. Taking a mortgage puts down the deposit, invests the rest of the cash on day one, and pays the mortgage each month. Each ends as investments minus any mortgage still owed; the home is the same on both paths, so it cancels out.

Unless you type your own, the home is the average UK home or typical US home in the month you buy, at the average new two-year fix (UK, refixed every two years) or 30-year fixed rate (US). UK rates are for a 75% loan; deals with a smaller deposit usually cost more, so type your own rate for those. In the US, a down payment under 20% adds mortgage insurance (PMI) at 0.5% of the loan a year until the loan falls to 78% of the price. Returns are tax-free with no fund fees, as in an ISA or a Roth IRA. Mortgage fees, the US mortgage interest deduction and tax outside those wrappers are left out.

Worked example

These use the calculator's starting figures for one UK and one US case, and are refreshed when the data updates.

Had you bought a £175,636 home in January 2015 with a mortgage and a 25% deposit, putting the other £131,727 into the stock market, instead of paying cash, by August 2026 you'd be £396,000 better off with the mortgage.

Had you bought a $189,012 home in January 2015 with a mortgage and 20% down, putting the other $151,210 into the stock market, instead of paying cash, by August 2026 you'd be $336,000 better off with the mortgage.

Where the numbers come from

  • UK: mortgage rates, savings rates and exchange rates from the Bank of England. House prices from the HM Land Registry UK House Price Index. Stock market: S&P 500 with dividends, from Robert J. Shiller's data. Contains HM Land Registry data © Crown copyright and database right 2026, licensed under the Open Government Licence v3.0.
  • US: mortgage rates from Freddie Mac 30-year fixed, via FRED. Treasury bills from the Federal Reserve, via FRED. Home values: Data Provided by Zillow Group. Stock market: S&P 500 with dividends, from Robert J. Shiller's data.

Questions

Should I pay cash for a house or get a mortgage?

This page can't say what will happen next, only what would have happened. Pick UK or US and the year you bought above: when stock returns beat the mortgage rate over those years, the mortgage path came out ahead, and when they didn't, paying cash did. "How it played out" also shows how far behind the winner fell along the way; borrowing to invest means riding out crashes with a mortgage to pay.

Is it better to buy property with cash or a mortgage?

Try a few start years above. From 2000 or 2007, the market fell soon after buying and the mortgage path spent years behind; from 2009 or 2012, low rates and strong returns put it well ahead. The gap grows with a smaller deposit, because more money is borrowed and more is invested.

What deposit should I compare?

Pick anything from 5% to 75%. A bigger deposit borrows less, so the result sits closer to paying cash. In the UK the average rate is for a 75% loan, so for a 5% or 10% deposit type in the higher rate you'd have been offered. In the US, under 20% down adds mortgage insurance until the loan falls to 78% of the price.

What if I kept the cash in savings instead?

Pick "Savings" above. The cash not spent on the home earns real savings rates instead of stock returns: the Bank of England average one-year fixed-rate bond rate in the UK, the 3-month Treasury bill yield in the US. With savings, the mortgage usually costs more than the cash earns, so paying cash tends to win.

Does it count the mortgage interest tax deduction?

No. Most US households take the standard deduction and get nothing from it. If you itemise, the mortgage cost you less after tax than shown here, which would tilt the result towards the mortgage.