Math & Numbers
Percentage, ratio, proportion, scientific notation, and Roman numeral tools
Tools
Select a tool to get started
Percentage Calculator
Calculate percentages: find a percentage of a number, what percent one number is of another, or the percentage change between two values.
Percentage Increase Calculator
Calculate the result of increasing a value by a given percentage.
Proportion Calculator
Solve proportions by finding the missing value D in the equation A/B = C/D.
Ratio Calculator
Simplify a ratio of two numbers using the greatest common divisor, and see it as a decimal and percentage.
Roman Numeral Converter
Convert between Roman numerals and decimal numbers (1–3999).
Scientific Notation Converter
Convert numbers between standard decimal form and scientific notation.
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