Ad-Efficiency
Free tool, no signup

Percentage Calculator

Three everyday percentage questions, answered live as you type. Plain-English sentences, a small visual, and exact math.

Answer
20% of 150 is
30
Sentence
What is % of ?
Formula(20 / 100) x 150
Result30

Running ads? Get a free 48-hour audit

Visual
30of 150
Part: 30 (20%)
Whole: 150
Related calculators

Keep exploring

ROAS calculator

Return on ad spend as a ratio and a percentage, with break-even check.

PPC metrics calculator

CTR, CPC, CPM, CVR, CPA and ROAS from clicks, impressions, cost, conversions.

Markup vs margin calculator

Convert between cost, markup, margin and selling price.

FAQ

Common questions

How do I calculate X% of Y?

Multiply Y by X divided by 100. For example, 20% of 150 is 150 x 0.20 = 30.

How do I calculate what percent one number is of another?

Divide the part by the whole, then multiply by 100. For example, 30 out of 150 is 30 / 150 x 100 = 20%.

How is percentage change calculated?

Percentage change = (new - old) / |old| x 100. A positive result is an increase, a negative result is a decrease.

What if the whole or old value is zero?

Percent-of and percentage change need a non-zero base. The tool shows a friendly note and skips the percentage in that case.

How many decimal places do you show?

Answers are rounded to two decimal places. The math itself uses full precision.