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Everyday math, shown step by step
Percentages, age, dates, hours, ratios and averages. Type your numbers and the answer appears, with the formula behind it.
Percentages
Percentage calculators
Percentage Calculator
Find X% of Y, what percent one number is of another, or the whole from a part.
Open calculator →Percentage Increase Calculator
Find the percent increase between two numbers, or raise a number by a percentage.
Open calculator →Percentage Decrease Calculator
Find the percent decrease between two numbers, or reduce a number by a percentage.
Open calculator →Percent Change Calculator
Percent change between two values, plus the symmetric percent difference.
Open calculator →Dates and time
Age, date and hours calculators
Age Calculator
Exact age in years, months and days, with total days and your next birthday.
Open calculator →Days Between Dates Calculator
Days, weeks, months and working days between any two dates.
Open calculator →Date Calculator
Add or subtract days, months and years and see the date and weekday.
Open calculator →Hours Calculator
Hours worked between start and end times, with breaks, in H:MM and decimal hours.
Open calculator →Numbers
Ratios and averages
Why these
Numbers you can check
The formula is always shown
Every page states the arithmetic it uses, with worked examples, so you can check the answer yourself.
Instant answers
Results update as you type. No button to press, no sign-up, no ads in the way of the result.
Private
Everything is calculated in your browser. Dates of birth and other figures are never uploaded.
Guides
Understand the formulas
Percentage formulas explained: of, is-what-percent and percent change
The formulas, worked examples, and the mistakes that trip people up.
Read guide →How to count days between dates: inclusive, exclusive and working days
Inclusive vs exclusive counting, month lengths, leap years and working days.
Read guide →