Calculators

Simple calculators with the working shown, so you can trust the answer.

7 free tools · No sign-up · Works on any device

Most used

Popular Calculators tools

Start here — these are the ones people use most.

Percentage Calculator
Work out percentages, percentage change, increases and discounts.
FreePopular
BMI Calculator
Work out your body mass index in metric or US units, with the healthy weight range for your height.
FreePopular

Everything

All Calculators

Percentage Calculator
Work out percentages, percentage change, increases and discounts.
FreePopular
Age Calculator
Find an exact age in years, months and days — and the days to the next birthday.
Free
BMI Calculator
Work out your body mass index in metric or US units, with the healthy weight range for your height.
FreePopular
GPA Calculator
Calculate your semester and cumulative GPA from letter grades and credits.
Free
Tip Calculator
Work out the tip and split the bill between any number of people.
Free
Calorie Calculator
Estimate how many calories you need each day to maintain, lose or gain weight.
Free
Days Between Dates
Count the days, weeks and weekdays between two dates.
Free

Learn

Helpful Calculators guides

Step-by-step explanations that go with the tools above.

Calculators
Explainer
How to Calculate Percentage Change (and the Mistakes Everyone Makes)
The percentage change formula with worked examples, plus percent vs percentage points, reversing a discount, negative values and multi-year growth.
Oct 1, 2026 · 5 min readRead

FAQ

Calculators: common questions

Do the calculators show how they got the answer?

Yes — each one shows the formula it used, so you can check it yourself.

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