DailyCalc

Percentage Calculator

Percent of a number, percentage change, increases, decreases and more.

What do you want to calculate?
%

Result

30

20% of 150 is 30.

Working
150 × 20 ÷ 100 = 30

Fix the highlighted field to update the result.

How to use

  1. Pick a calculation at the top.
  2. Enter two numbers. A % sign is fine.
  3. Read the answer, a plain sentence and the working.

Percentage formulas

Question Formula Example
P% of X X × P ÷ 100 20% of 150 = 30
X is what % of Y X ÷ Y × 100 1.5 of 30 = 5%
% change from A to B (B − A) ÷ |A| × 100 80 → 100 = +25%
Increase X by P% X × (1 + P ÷ 100) 500 + 10% = 550
Decrease X by P% X × (1 − P ÷ 100) 500 − 10% = 450
Original before +P% Y ÷ (1 + P ÷ 100) 550 → 500
% difference |A − B| ÷ average × 100 10 and 6 → 50%

Examples

  • Discount: 80 with 25% off is 80 × 0.75 = 60
  • Pay rise: 18 to 19.80 is +10%
  • Price before tax: 115 including 15% tax was 115 ÷ 1.15 = 100, not 97.75
  • Points vs percent: 10% to 12% is +2 points, which is a 20% rise

Percent, decimal and fraction

Percent Decimal Fraction
1% 0.01 1/100
5% 0.05 1/20
10% 0.1 1/10
12.5% 0.125 1/8
20% 0.2 1/5
25% 0.25 1/4
33.33…% 0.333… 1/3
50% 0.5 1/2
75% 0.75 3/4
Why +10% then −10% doesn’t get you back

Each step starts from a different number. 500 + 10% is 550. Then 10% of 550 is 55, so you end at 495.

To undo a 10% rise, divide by 1.10 instead. That is what the Original before % mode does.

Negative starting values

Percentage change is measured against the size of the starting value. So a loss shrinking from −50 to −25 counts as +50%.

Working out loan repayments? Try the loan and EMI calculator.

Frequently asked questions

How do I work out a percentage of a number?

Divide the percentage by 100, then multiply. For example, 20% of 150 is 0.20 × 150 = 30.

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

Divide the part by the whole and multiply by 100. For example, 1.5 out of 30 is 5%.

How do I calculate percentage increase or decrease?

Subtract the old value from the new one, divide by the old value, then multiply by 100. Going from 80 to 100 is +25%.

What is the difference between percent and percentage points?

Points are the plain gap between two percentages. Going from 10% to 12% is +2 percentage points, but a 20% relative increase.

Why doesn’t +10% then −10% get me back to the start?

Each step uses a different starting value. 500 + 10% is 550, and 550 − 10% is 495. To undo +10%, divide by 1.10.

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