Both have free money calculators, and they answer different questions. Calculator.net's calculators project forward from rates you set. Ctrl Alt Decide replays what really happened at a real place and date.
| Calculator.net | Ctrl Alt Decide | |
|---|---|---|
| What it answers | What might happen: it projects forward from rates you enter. | How a choice turned out: it replays what really happened at a real place and date. |
| Where the numbers come from | Rates you enter, such as "Home value appreciation (/ year)", "Rental fee increase (/ year)" and "Average investment return". | Published records for your place and month: HM Land Registry, ONS, Zillow, Freddie Mac, Bank of England and more. You can type over any figure. |
| Rent or buy | Yes, projected forward from the rates above, with US federal and state tax inputs. | Yes, for over 600 UK and US places, back to 2015. |
| Overpay the mortgage or invest | A mortgage payoff calculator. Investing instead is mentioned in the text, not calculated. | Yes: overpaying against investing, back to 2000. |
| Lease or buy a car | An auto lease payment calculator. No lease against buy comparison found. | Yes: leasing, a car loan or paying cash, compared. |
| Savings or investing | Savings, compound interest and investment calculators, with a return you set. | Cash savings against the stock market, with real savings rates and returns back to 2000. |
| Moving city | None found. | Pay, rents and house prices in two places, replayed since 2015. |
| Pay against inflation | An inflation calculator that converts a dollar amount between months with the US consumer price index. No pay comparison. US only. | Yes: your pay then and now against prices and real average pay, UK and US, back to 2000. |
| Stock markets by country | An investment calculator with a return rate you enter. No real past returns and no other countries. | Yes: two countries' real share prices side by side, in pounds or dollars, back to 2000. |
| UK coverage | Mostly US. It has a UK mortgage calculator with stamp duty, but no UK rent vs buy. | UK and US. |
| Account needed | Not needed. An account is optional, for saving calculations. | Not needed. |
| How it makes money | Advertising. | No ads, no affiliate links, no paid version. |
You need a quick general calculator for almost anything, from loans to maths to health, or a simple UK mortgage payment with stamp duty.
You want to know how a choice actually played out: in your place, from the month you made it, with the real prices, rents and rates since. It covers the UK as well as the US, and every figure names its source.
Checked on 23 September 2026 against Calculator.net's own pages: Calculator.net rent vs buy calculator, About Calculator.net. Spotted something out of date? Tell us at @ctrlaltdecide.