What's the difference between percentage change and percentage difference?

Percentage change has a direction (from A to B) and uses A as the base. Percentage difference is symmetric and uses the mean of A and B as the base.

Can I use negative numbers?

Yes. Negative values work in every mode; the sign of the result reflects direction (e.g. a negative change means a decrease).

Does the calculator round results?

Results are shown with up to 6 decimal places, trimmed of trailing zeros.

How do I calculate 20% of 80?

Convert 20% to 0.20, then multiply by 80. The result is 16.

How do I find what percent 30 is of 200?

Divide 30 by 200 and multiply by 100. 30 / 200 x 100 = 15%.

Percentage Calculator - CalculatorBox

Quick percentage formulas

Use these three formulas for most percentage questions:

X percent of Y = (X / 100) × Y
X is what percent of Y = (X / Y) × 100
Percentage change = (new value - old value) / old value × 100

For example, 15% of 200 = 30, because 15 / 100 × 200 = 30. If a price rises from 80 to 100, the percentage increase is 25%, because (100 - 80) / 80 × 100 = 25%.

How to use the Percentage Calculator

Pick one of three modes:

% of — Find X% of a number (e.g. 15% of 200 = 30).
% change — Compute the percent change from one value to another.
is what % — Find what percentage the first number is of the second.

Enter the values exactly as they appear in your problem. The result updates instantly and keeps enough decimal places for homework, budgeting, finance checks and everyday comparisons.

Formula & examples

% of:       result  = (percent / 100) × value
% change:   result  = (to − from) / from × 100%
is what %:  result  = part / whole × 100%

Question	Formula	Answer
What is 12% of 50?	12 / 100 × 50	6
18 is what percent of 60?	18 / 60 × 100	30%
Increase from 40 to 50	(50 - 40) / 40 × 100	25%
Decrease from 80 to 68	(68 - 80) / 80 × 100	-15%
7 out of 25 as a percent	7 / 25 × 100	28%

Percentage increase vs percentage decrease

Percentage change always depends on the starting value. Moving from 50 to 75 is a 50% increase, but moving from 75 back to 50 is a 33.333% decrease. The size of the change is the same in absolute terms (25), but the base value is different.

Increase: (75 - 50) / 50 × 100 = 50%
Decrease: (50 - 75) / 75 × 100 = -33.333%

Percentage vs percentage points

A change from 4% to 6% is an increase of 2 percentage points. It is also a 50% relative increase, because (6 - 4) / 4 × 100 = 50%. Use percentage points when comparing two percentages directly, such as interest rates, poll numbers or conversion rates.

Common pitfalls

A 50% increase followed by a 50% decrease does not return to the original value (1 × 1.5 × 0.5 = 0.75).
Don’t average percentages without weighting — average the underlying counts instead.
Be careful with zero as the starting value. Percentage change from zero is undefined because the formula divides by the old value.
A negative percentage change means a decrease; a negative input can change the interpretation depending on the context.

Common use cases

Shopping and discounts — calculate sale prices, tips, taxes and markdowns.
Finance — compare returns, interest rates, growth rates and fees.
School and grades — convert points earned into a grade percentage.
Business metrics — measure conversion rate, completion rate, churn, margin and month-over-month change.
Everyday ratios — turn part-whole comparisons into a clear percent.

Percentage Calculator