Home/ Calculators/ Percentage Calculator
Percentage Calculator
Four everyday percentage questions, including the one people get wrong.
Runs in your browser Nothing is uploaded Free, no sign-up
Result
—
Four calculations cover almost every percentage question that comes up in a working day.
The four
What is X% of Y — discounts, tips, commission. X is what percent of Y — share of a total. Percentage change from X to Y — growth, drops, variance against budget. And X is Y% of what — working backwards from a part to the whole, which is how you recover a base from a commission figure.
The asymmetry people miss
A 50% fall needs a 100% rise to get back. A stock down 80% needs to quintuple to break even. Percentage changes are not symmetric, and treating them as if they were is how portfolios and sales forecasts both get misread.
Percentage points
A rate moving from 5% to 6% is one percentage point, but a 20% increase. Financial writing uses both, often in the same sentence. The distinction is worth insisting on.
Frequently asked questions
How do I calculate percentage change?
Subtract the old value from the new, divide by the old value, and multiply by 100. The base is always the starting figure, which is where most errors creep in.
Why is a 50% fall not reversed by a 50% rise?
Because the second percentage applies to a smaller base. A 50% fall needs a 100% rise to recover, and an 80% fall needs a 400% rise. Percentage changes are not symmetric.
What is the difference between percent and percentage points?
A rate moving from 5% to 6% has risen by one percentage point, but by 20% in relative terms. Financial writing uses both, often in the same sentence, so the distinction is worth insisting on.
How do I work backwards from a percentage?
If a figure is Y% of an unknown total, multiply it by 100 and divide by Y. The fourth mode of this calculator does that — useful for recovering a sale value from a commission amount.