Percentages & ratios
Percentage of, percentage change, reverse percentage and margin — the four cases people mix up daily. 16 tools, including Golden Ratio Calculator, Mass percent calculator, Odds Ratio Calculator and Percent off calculator. All free, with no account and nothing to install.
Golden Ratio CalculatorSplit a length in the golden ratio φ = (1+√5)/2: give the total, the larger or the smaller segment and get the other two, drawn to scale.Mass percent calculatorCompute the mass percent of a solute in a solution.Odds Ratio CalculatorCompute the odds ratio from a 2×2 table with its log-odds standard error, the Wald interval at 90/95/99 %, relative risk, risk difference — and the Haldane–Anscombe correction when a cell is zero.Percent off calculatorTake a percentage off a price: the amount you save and the final sale price. Enter the original price and the discount.Percent to Fraction CalculatorConvert a percentage into its reduced fraction and equivalent decimal (e.g. 12.5% → 1/8).Percentage calculatorFour percentage calculations in one: X% of Y, what percent X is of Y, and increasing or decreasing a value by a percentage.Percentage change calculatorFind the percentage increase or decrease between two numbers.Percentage decrease calculatorHow far a value fell from an old figure to a new one, as a percentage — and the absolute drop. A negative result means it actually rose.Percentage difference calculatorCompute the percentage difference between two values (relative to their average).Percentage error calculatorCompute the percentage error between a measured and a true value.Percentage increase calculatorBy how much a value grew from an old figure to a new one, as a percentage — and the absolute change. A negative result means it actually fell.Percentage point change calculatorFind the difference in percentage points between two percentages, and the relative change.Proportion calculatorSolve a proportion a/b = c/x and find the missing value x.Ratio calculatorSimplify a ratio to its lowest terms and see it as a decimal.Reverse percentage calculatorFind the whole when you know that a value is a given percentage of it.Rule of threeSolve a proportion: if A gives B, what does C give?