7.50
A 15% tip on a bill of 50 is 7.50, making the total 57.50. To find any tip, multiply the bill by the tip rate as a decimal (50 × 0.15 = 7.50). Enter your own bill and rate in the calculator below.
Five quick percentage tools: what is X% of Y, what percent one number is of another, percentage change, percentage difference, and adding or subtracting a percent.
X% of Y
12
X ÷ Y × 100
15%
From an old value to a new value
15% · increase
Between two values (order doesn't matter)
40%
Base ± percent
plus 92 · minus 68
A percentage is a fraction of 100. To find X% of Y, multiply Y by X/100. To find what percent one number is of another, divide and multiply by 100.
Percentage change measures growth from an old value to a new one relative to the old value. Percentage difference compares two values relative to their average, so the order doesn't matter.
Percentage change is directional — it compares a new value against an original (old) value. Percentage difference is symmetric — it compares two values against their average, so swapping them gives the same answer.
Yes. Every mode accepts negative and decimal values. A few inputs have no defined answer, so they're blocked: the total (Y) in 'X is what percent of Y' and the starting value in percentage change can't be zero, and percentage difference needs at least one non-zero value.
It is handy for tax, tips, discounts, and markups: enter a base amount and a percent to see the value with the percent added and with it subtracted at the same time.
Each mode uses a direct formula. "What is X% of Y" computes (X / 100) × Y. "X is what % of Y" computes (X / Y) × 100, requiring Y ≠ 0. Percentage change is ((new − old) / |old|) × 100, signed, requiring the old value ≠ 0. Percentage difference is |A − B| / ((|A| + |B|) / 2) × 100, order-independent, requiring the two values not both be zero. "Add / subtract a percent" gives base × (1 + p / 100) and base × (1 − p / 100). All formulas follow standard mathematical definitions as documented on MathIsFun.
Reviewed by the YouCalc Team · Last reviewed
Spot a translation issue, a calculation issue, or have a suggestion? Let us know.