Calculator Tools

Percentage Calculator

Find a part, a percentage, a whole, or the change between two values.

What would you like to calculate?

What is X% of Y?

Use a decimal point, without commas or symbols. In a percentage field, 15 means 15%.

Your numbers stay in this browser. No account needed.

Result

Start with your question.

Enter two numbers and select Calculate. Your answer and the calculation will appear here.

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Choose the calculation that fits

Start with what you know and what you need to find. Use the same units for both values.

Find a part

What is 15% of 240?

36

240 × 15 ÷ 100 = 36. This could be the amount of a discount. The price after that discount would be 204, not 36.

Find a percentage

42 is what percent of 60?

70%

42 ÷ 60 × 100 = 70%. Useful for a score or a share of a total. This does not assign a grade or decide a pass mark.

Find the whole

30 is 20% of what?

150

30 × 100 ÷ 20 = 150. If 30 is the price after 20% off, it represents 80% of the original price instead.

Find percentage change

What changed from 80 to 100?

25% increase

(100 − 80) ÷ 80 × 100 = 25%. Reversing the values gives a 20% decrease: the original value is always the base.

Small details that change the answer

Percentage change or percentage points?

A rate moving from 20% to 25% rises by 5 percentage points, but its relative increase is (25 − 20) ÷ 20 × 100 = 25%. This calculator returns relative change, not percentage-point difference or the symmetric percentage difference.

Can I use zero, negative numbers or more than 100%?

The first three modes allow signed values and percentages above 100. A whole of zero cannot be the base for a percentage; a zero percentage cannot determine a unique whole. Percentage change requires an original value greater than zero. A new value can be negative: 100 to −20 is a 120% decrease. Signed ratios are algebraic relations, not necessarily meaningful shares of a population.

What are the input and rounding limits?

Enter up to 6 decimal places and an absolute value of up to 1 trillion. Trailing zeros do not count toward the decimal limit. Use a dot; omit commas, percent signs, currency symbols and exponent notation. Each field accepts at most 64 characters. Results are calculated using exact decimal relationships and rounded once to at most 6 decimal places, with midpoint values rounded away from zero. Very small nonzero answers use scientific notation with up to 6 significant digits. The ≈ symbol means the answer was rounded.

Are these currency or interest calculations?

No currency, interest period, tax rules or unit conversions are assumed. An answer is not automatically rounded to cents. The calculator handles the four stated mathematical relationships, not compound interest, loan payments or tax advice.

Do my numbers leave this device?

Calculations run in browser memory. Numbers, answers and formulas are not uploaded or stored. Copying is optional. Only a rating or message you choose to send goes to the feedback service; calculation content is never attached. Local development and QA visits send no analytics.