Percentage Calculator

Choose a calculation type, enter values, and see the result with stepby step explanation.

What is a percentage?

A percentage is a way to express a number as a fraction of 100. It shows how one quantity compares to another and is written with the % symbol. For example, 35% equals 0.35 in decimal form or 35/100 as a fraction.

How to compute it

Convert the ratio to a decimal, then multiply by 100. Example: 25 out of 50 students are male.

25 ÷ 50 = 0.5
0.5 × 100 = 50%

So, 50% of the students are male.

General percentage formula

The percentage relationship can be written as:

P × V₁ = V₂

Where P is the percentage (decimal), V₁ is the original value, and V₂ is the result.

Examples

Find P:

P × 30 = 1.5
P = 1.5 ÷ 30 = 0.05 = 5%

Remember to multiply by 100 when converting a decimal to percent.

Increase / Decrease

Increase 500 by 10%: 500 × (1 + 0.10) = 550
Decrease 500 by 10%: 500 × (1 - 0.10) = 450

Percentage difference

Percentage difference compares two values relative to their average:

Percentage Difference = |V₁ - V₂| ÷ ((V₁ + V₂) / 2) × 100

Example: between 10 and 6

|10 - 6| ÷ ((10 + 6) / 2) = 4 ÷ 8 = 0.5 = 50%

Percentage change

Percentage change shows how much a value has increased or decreased compared to the original:

Percentage Change = (V_new - V_old) ÷ V_old × 100

Use this formula to report increases or decreases as a percent of the starting value.