What is 30% of 300?

Percentage: 30%
Of: 300
Result: 90

30% of 300 is 90. The easiest path is to find 10% (move the decimal one place: 30) and multiply by 3, giving 90. As a decimal it is 0.30 × 300 = 90. Try any percentage and number in the calculator below.

Math

Percentage Calculator

Six quick percentage tools: what is X% of Y, what percent one number is of another, X is P% of what, percentage change, percentage difference, and adding or subtracting a percent.

What is X% of Y?

X% of Y

Percent (X)

Of (Y)

X is what percent of Y?

X ÷ Y × 100

Number (X)

Total (Y)

15%

Percentage change

From an old value to a new value

From (old)

To (new)

15% · increase

Percentage difference

Between two values (order doesn't matter)

Value A

Value B

40%

Add or subtract a percent

Base ± percent

Base value

Percent (%)

plus 92 · minus 68

X is P% of what?

X ÷ (P ÷ 100)

Number (X)

Percent (P)

How it's calculated

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. "X is P% of what" solves for the base as X / (P / 100), requiring P ≠ 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.

Sources

Reviewed by the YouCalc Team · Last reviewedJune 11, 2026

Results are estimates. Verify with a professional for important decisions.

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