Work with quantities, percentages, fractions, ratios, units and numerical precision. These tools help turn a practical question into comparable numbers.
Which calculator should I use?
Choose percentages for change or part-of-whole questions, ratios for proportional relationships, and unit conversion before comparing measurements. Use rounding and error to understand the precision of a reported answer.
Available calculators
Ratio and Proportion Calculator
Simplify a ratio, find an equivalent ratio, solve a proportion, or interpret parts of a whole.
Percentage Calculator
Find a percent of a value, express a part as a percent, apply a change, or recover an original value.
Fraction Calculator
Exact fraction arithmetic and comparison, plus mixed-number and decimal forms.
Rate, Unit Rate, and Variation Calculator
Find a unit rate, scale it, or calculate direct and inverse variation.
Number Properties Calculator
Explore factorization, divisors, multiples, parity, greatest common factor, and least common multiple.
Rounding, Significant Figures, and Error Calculator
Round to decimal places or significant figures and calculate absolute, relative, or percent error.
Unit Conversion Calculator
Convert compatible length, area, volume, mass, temperature, time, speed, and data units.