About Ctrl Alt Decide
Free what-if calculators that replay real UK and US prices, rents and rates, so you can see how a money decision turned out on both paths.
Why it exists
Most money calculators ask you to guess the future: a growth rate, an inflation rate, a return. Change the guess and the answer flips. This site does the opposite. It takes a decision someone made, or could have made, at a real place and date, and replays what the published records say happened next. Both paths get the same money going in, so the gap between them is the difference the choice made.
It's built for people making their own money decisions: renters, homeowners and savers. It isn't a tool for financial advisers or businesses.
The calculators: rent vs buy, overpay the mortgage or invest, lease vs buy a car, savings vs investing and move or stay. There's also a table of where buying beat renting since 2015.
Who made it
Leon Ross
I wanted one place for the common what-if money scenarios, like renting or buying and saving or investing, answered with what actually happened rather than guesses.
Each calculator replays published UK and US prices, rents and rates from a real start date and charts both choices side by side.
Ctrl Alt Decide is independent. It isn't owned or paid by a bank, lender, broker or adviser. Questions, or a number that looks wrong? Tell me on X at @ctrlaltdecide.
How it makes money
It doesn't. There are no ads, no affiliate links, no sponsored content and no paid version. Nobody pays to be recommended, because nothing is recommended.
Where the numbers come from
- UK: HM Land Registry UK House Price Index (house prices), ONS Price Index of Private Rents (rents), ONS consumer price indices (inflation and car prices), ONS earnings from PAYE Real Time Information (pay), and the Bank of England (mortgage, savings and loan rates, exchange rates). UK data is Crown copyright, used under the Open Government Licence v3.0.
- US: Zillow (home values and rents; Data Provided by Zillow Group), Freddie Mac 30-year fixed rates via FRED, the Federal Reserve (Treasury bills, car loan rates), BLS (inflation, car prices, pay) and the Census ACS (property tax).
- Both: S&P 500 returns with dividends, from Robert J. Shiller's data.
Each calculator lists its sources at the foot of the page, and you can type over any figure it fills in.
Privacy
No accounts and no ads. The calculations run in your browser. The site uses HeyCatch analytics to see which pages and buttons get used; it keeps an anonymous visitor ID in a cookie and in your browser's storage. Your last inputs are kept in your browser's storage so a calculator opens where you left off; clearing the site's data removes them. A share link carries your inputs in the address, so anyone you send it to sees them. Fonts and the analytics code load from Google Fonts and esm.sh, and the site is hosted on Cloudflare; like any web host, they see standard request details such as your IP address.
Not advice
Everything here is for illustration, not financial advice. It shows what happened to real prices and rates in the past. It can't say what happens next, and it doesn't know your whole situation.