math calculators
Math calculators
Tools to solve percentage, proportion, age, and day counts without doing the math by hand. Enter your values and see instant results, with no sign-up required and no ads hiding your answer.
All tools
Percentage calculator
Calculate percentages, proportions, and variations.
ΣAge calculator
Exact age in years, months, and days.
ΣRule of three
Find proportions automatically.
ΣDays between two dates
Days, weeks, months, and business days between dates.
x̄Average calculator
Calculate simple average, weighted average, and the grade you still need.
x̄Weighted average calculator
Weighted average with the relative weight of each item.
No tool found. Try another term.
Frequently Asked Questions
How do you calculate a percentage of a value?
Simply multiply the value by the desired percentage and divide by 100. Our calculator also works in reverse: calculating what percentage one number is of another, or the percentage change between two values.
What is the rule of three?
It is a mathematical method to find an unknown value based on a proportion between known quantities. It can be simple (involving two quantities) or compound (involving three or more related quantities).
Does the days between dates calculator count business days?
Yes, in addition to total calendar days, it also displays the count in weeks, months, and business days between the two selected dates.