Percentage Calculator
Calculate percentages, changes, discounts and reverse-percentage problems.
Pick the shape of your problem — "X% of Y", "X is what percent of Y", percentage increase/decrease, tip/tax/discount — and get the answer without rearranging the formula in your head. Each shape is exposed as its own form so you don't have to remember which value goes where.
Common use cases: calculating tips and tax-inclusive prices, comparing year-over-year growth, working out discount-adjusted prices, computing portfolio returns, and sanity-checking percentage figures in reports and analytics dashboards.
Percentage Calculation
25 is X% of 100
%
Change from 100 to 25
%
Frequently asked questions
What's the difference between "X% of Y" and "X is what percent of Y"?
"20% of 80" is multiplication:
0.2 × 80 = 16. "16 is what percent of 80" is division: 16 / 80 = 0.2 = 20%. Both are the same equation rearranged — useful to have both directions ready when working back from a number.Why isn't a 50% drop cancelled by a 50% rise?
Because the second percentage operates on a smaller base.
100 → -50% → 50 → +50% → 75, not 100. To get back to the original after a 50% drop you need a 100% rise. This is why short-term percentage swings on the same instrument look misleadingly symmetric.When should I use percentage points instead of percent?
When comparing two percentages directly. Going from a 5% interest rate to 7% is a 2 percentage point increase, but a 40% relative increase. Mixing the two terms is a common source of confusion in news articles and reports.
How do I compute tip, tax or discount cleanly?
Tip/tax: multiply the base by
1 + rate. Discount: multiply by 1 - rate. Reverse a tax-inclusive price: divide by 1 + rate. The calculator handles each shape directly.