Percentage, loan repayment, compound interest, BMI, age and discount calculators that show their working rather than just an answer.
The tools
Ordered by how often they are used. Every one is free and runs in your browser.
Background
A calculator that returns a single number is only half a tool. The useful part is understanding how the answer was reached — which is why every calculator here shows the intermediate figures, the formula applied and, where relevant, a breakdown over time.
That matters most for money. Seeing that a loan's total interest exceeds a third of the amount borrowed, or that an extra £50 a month removes four years from a mortgage, changes decisions in a way that a bare monthly-payment figure never does.
All calculations run instantly in your browser as you adjust the inputs, so you can explore scenarios freely. Nothing you enter is transmitted or stored, which makes these safe to use with real salary, loan and health figures.
What people ask most about calculators and how ours work.
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