Percentage Calculator

Calculate percentages in multiple ways

A percentage is a ratio expressed as a fraction of 100, used to describe proportions, changes, and comparisons — calculated as (part / whole) × 100.

What is X% of Y?

What is % of ?

Result

X is what % of Y?

is what % of ?

25%

Percentage

Percentage Change

From to

+25%

Change

Increase/Decrease by %

increased by %

115

New Value

GPA Calculator

Course Name Grade Credits

0.00

Cumulative GPA

Total Credits: 0

Percentage Formulas

Basic Percentage

To find X% of Y: multiply Y by X/100. Example: 25% of 200 = 200 x 0.25 = 50

Percentage Change

Change = ((New – Old) / Old) x 100. Positive result means increase, negative means decrease.

Common Percentages

10% = 1/10, 20% = 1/5, 25% = 1/4, 33.3% = 1/3, 50% = 1/2, 75% = 3/4

GPA Scale

The US uses a 4.0 scale. GPA is weighted by credit hours: multiply each course’s grade points by its credits, sum all, then divide by total credits. Latin honors: Summa Cum Laude (3.7+), Magna Cum Laude (3.5+), Cum Laude (3.2+).

Frequently Asked Questions

How do you calculate what percentage one number is of another?

Divide the part by the whole and multiply by 100. For example, 50 is what percent of 200? (50 / 200) × 100 = 25%. The calculator includes a dedicated section for this: enter the part (50) and the whole (200) to get 25% instantly.

How do you calculate percentage change between two values?

Percentage change = ((New − Old) / Old) × 100. From 80 to 100: ((100 − 80) / 80) × 100 = +25%. A positive result is an increase; negative is a decrease. Example: a price drop from 50 to 40 gives ((40 − 50) / 50) × 100 = −20% change.

How do you increase or decrease a number by a percentage?

To increase by p%: New = Original × (1 + p/100). To decrease by p%: New = Original × (1 − p/100). A $100 item with a 15% increase becomes $100 × 1.15 = $115. A 20% discount off $80 gives $80 × 0.80 = $64.

How is GPA calculated and what is the 4.0 scale?

GPA is the weighted average of grade points, weighted by credit hours. Multiply each course’s grade points (A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0) by its credits, sum all products, then divide by total credits. Two 3-credit courses with an A (4.0) and a B (3.0): GPA = (12 + 9) / 6 = 3.5.

What is a common mistake when calculating percentage change versus percentage points?

Percentage change and percentage points are different. If interest rates rise from 2% to 3%, that is a 1 percentage-point increase but a 50% percentage change ((3−2)/2 × 100 = 50%). Confusing the two leads to errors — always clarify which metric is being discussed when comparing rates or shares.