Math & Numbers
Math & Numbers Calculators
Work through common percentage, fraction, and ratio calculations without rebuilding the formula by hand.
Math & Numbers
Percentage Calculator
Calculate a percentage of a number, find what percent one number is of another, and calculate percentage change.
CalculateMath & NumbersFraction Calculator
Add, subtract, multiply, divide, and simplify fractions with instant results.
CalculateMath & NumbersRatio Calculator
Simplify ratios and scale both parts by a multiplier to find equivalent ratios.
CalculateSolve percentages, fractions, and ratios
Choose the tool for the relationship you are trying to calculate. Percentages compare a part with a whole, fractions represent parts of a unit, and ratios compare quantities with each other.
- Find a percentage of a number by multiplying the number by the percentage divided by 100. For percentage change, compare the difference with the original value.
- When adding or subtracting fractions, use a common denominator before combining the numerators. Multiplication and division follow different rules, so use the operation that matches your problem.
- Simplify a ratio by dividing each part by the same common factor. To scale a ratio, multiply each part by the same factor to preserve the relationship.
- Check what the result represents and keep units consistent. A percentage change also depends on the chosen starting value, and it cannot be calculated when that baseline is zero.
Example: calculate a percentage and scale a ratio
Twenty percent of 150 is 150 × 0.20 = 30. Separately, scaling the ratio 2:3 by a factor of 4 gives 8:12, which preserves the original relationship.