Maths everyone does by hand, or doesn't do: whether instalments beat cash with the inflation you expect, how to split your salary, who owes whom after the barbecue. Each calculator runs in the browser, asks for no account, and the result is shareable with a link. The figures it needs, inflation and rates, you enter yourself: none has a number built in that could go stale.
The calculators
- Instalments vs cashIs it better to pay in instalments or in cash?Enter the cash price, the instalment total and the inflation you expect: the calculator shows what the instalments are worth today and which costs less.
- 50/30/20 rule50/30/20 rule calculatorEnter your net income and the calculator splits it into needs, wants and savings using the 50/30/20 rule. With adjustable percentages and a worked example.
- Split expensesSplit expenses with friends: who owes whomEnter who's in and what each person paid: the calculator splits equally and tells you who pays whom with the fewest transfers. No sign-up.
How they're made
- No sign-up and nothing to install. What you type stays in the page's address, which is what you share.
- The formula and a worked example are written on every page, to understand the maths and not just see the number.
- No figure that changes over time is built in: you enter the inflation or the rate, and the page says where to get it, with a source.
- None of them makes a recommendation. They do the maths with your assumptions and say what comes out under those assumptions.
Educational content. No calculator is financial advice or a recommendation to buy or invest.
Frequently asked questions
Are the calculators free?
Yes, and with no sign-up. They run in your browser and store nothing on any server.
Why doesn't the instalments calculator come with inflation filled in?
Because any number written there would be read as official and go stale the following month. You enter it; the page says where the latest published figure is.
Will more calculators be added?
Yes. Next in the plan: emergency fund, how much to save per month for a goal, fixed-term deposits and inflation, and a monthly budget template. They show up on this page when published.