percentage calculator

Percentage Calculator

Three modes: X% of Y, what percentage X is of Y, and percentage change from X to Y.

What each mode does

  • X% of Y — multiply Y by X ÷ 100. Handy for tips, taxes, and sale discounts. Example: 20% of 150 = 30.
  • X is what % of Y— divide X by Y and multiply by 100. Answers “what percentage is X of Y?”. Example: 30 is what % of 90 → 33.33 %.
  • % change from X to Y — (Y − X) ÷ X × 100. Positive for an increase, negative for a decrease. Example: 100 → 125 = +25 %; 200 → 150 = −25 %.

Plain-language questions

If your question does not fit neatly into one of the three modes, use the AskClaude helper below — it accepts natural phrasing like “what is 15 % of my $84 restaurant bill” or “my rent went from $1500 to $1620, what percent raise is that?”.

Related: tip calculator, loan calculator, compound interest calculator, and take-home pay calculator.

AIAsk any percentage question

Frequently asked

What percentage is X of Y?
Switch to the "X is what % of Y" mode, enter X in the first field and Y in the second. The tool divides X by Y and multiplies by 100. Example: 30 is what % of 90 → 33.33 %. Same formula whether X is larger or smaller than Y.
What is X% of Y?
Use the "X% of Y" mode, enter the percentage first and the total second. The tool multiplies Y by X ÷ 100. Example: 20 % of 150 = 30. Handy for tips, taxes, sale discounts, and commission calculations.
How do I calculate percentage change?
Use the "% change" mode. Enter the original value first, then the new value. The formula is (new − original) ÷ original × 100. Positive numbers mean an increase, negative numbers a decrease. Example: from 100 to 125 is a +25 % change; from 200 to 150 is a −25 % change.
Can I ask a percentage question in plain language?
Yes. The AskClaude helper below the calculator accepts natural-language questions like "what is 15 % of my $84 restaurant bill" or "my rent went from $1500 to $1620, what percent raise is that?", useful when the number arrangement does not fit neatly into one of the three modes.