How do I calculate percentage change?

Percentage change = ((New Value - Old Value) / |Old Value|) x 100. If the result is positive, it's an increase; if negative, it's a decrease. Example: from 80 to 100 = (100 - 80) / 80 x 100 = +25%. From 100 to 75 = (75 - 100) / 100 x 100 = -25%. The absolute value of the old value is used so the sign of the result reflects direction, not the sign of the original.

What is the formula for percentage increase?

To find the new value after a percentage increase: New Value = Original x (1 + Percentage / 100). Example: $200 with a 15% increase = 200 x 1.15 = $230. To find just the increase amount: Increase = Original x (Percentage / 100) = 200 x 0.15 = $30. This formula is used for salary raises, price markups, compound interest (one period), and population growth.

What is the formula for percentage decrease?

To find the new value after a percentage decrease: New Value = Original x (1 - Percentage / 100). Example: $150 with a 20% discount = 150 x 0.80 = $120. To find just the decrease amount: Decrease = Original x (Percentage / 100) = 150 x 0.20 = $30. This formula is used for discounts, depreciation, weight loss targets, and budget cuts.

What is the difference between percentage change and percentage difference?

Percentage change is directional: it measures change from a specific starting (old) value to a new value. Percentage difference is symmetric: it compares two values without implying which came first, using their average as the denominator. Formula: |V1 - V2| / ((|V1| + |V2|) / 2) x 100. Use percentage change for time-series comparisons; use percentage difference for comparing two measurements with no natural baseline.

Why is percentage change not symmetric?

Percentage change depends on the denominator (the old value), so going from 100 to 150 is a +50% change, but going from 150 back to 100 is a -33.3% change. This asymmetry is mathematically correct. To get a symmetric comparison, use percentage difference, which uses the average of both values as the base. Percentage difference for 100 and 150: |50| / 125 x 100 = 40%.

What is a good percentage increase for salary negotiation?

Typical salary increase benchmarks: Cost of living raise = 2-4% (maintains purchasing power). Merit raise = 5-10% (recognizes performance). Promotion = 10-20% (new responsibilities). Job change = 15-30% increase commonly expected for lateral moves. At or above inflation (currently ~3-4%) is needed to avoid a real-money pay cut. Use the % Increase mode: enter your current salary as the original value and the raise percentage to see your new salary instantly.

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Percentage Change Calculator

Percentage change = ((New - Old) / |Old|) x 100. Positive = increase, negative = decrease. Example: 100 to 150 = +50%; 150 to 100 = -33.3%. To find a new value after increase: New = Original x (1 + %/100). After decrease: New = Original x (1 - %/100). Percentage difference (symmetric) = |V1 - V2| / ((|V1|+|V2|)/2) x 100.

Calculate percentage change between two values, find the new value after a percentage increase or decrease, or compute the percentage difference between two numbers. Shows formula, direction, and absolute change instantly.

Calculation Type

Calculate the percentage change between an old value and a new value

Quick Examples

Enter Values

Old Value

New Value

Formula Reference

Calculation	Formula	Example
% Change	(New − Old) / \|Old\| × 100	(150−100)/100 = +50%
% Increase	Original × (1 + %/100)	100 × 1.25 = 125
% Decrease	Original × (1 − %/100)	100 × 0.75 = 75
% Difference	\|V1−V2\| / ((\|V1\|+\|V2\|)/2) × 100	\|40−60\| / 50 = 40%

How to Use

1
Choose the calculation type
Select % Change (old to new), % Increase (find new value after increase), % Decrease (find new value after decrease), or % Difference (symmetric comparison)
2
Enter your two values
Type the old and new values for % Change, or the original value and percentage for Increase/Decrease modes
3
View the instant result
The calculator auto-computes as you type, showing the percentage change, direction (increase or decrease), and absolute change amount
4
Check the formula
Review the formula reference table at the bottom to understand how the result was calculated
5
Copy your result
Click the copy button to save the full result (value, percentage, direction) to your clipboard

Frequently Asked Questions

How do I calculate percentage change?: Percentage change = ((New Value - Old Value) / |Old Value|) x 100. If the result is positive, it's an increase; if negative, it's a decrease. Example: from 80 to 100 = (100 - 80) / 80 x 100 = +25%. From 100 to 75 = (75 - 100) / 100 x 100 = -25%. The absolute value of the old value is used so the sign of the result reflects direction, not the sign of the original.
What is the formula for percentage increase?: To find the new value after a percentage increase: New Value = Original x (1 + Percentage / 100). Example: $200 with a 15% increase = 200 x 1.15 = $230. To find just the increase amount: Increase = Original x (Percentage / 100) = 200 x 0.15 = $30. This formula is used for salary raises, price markups, compound interest (one period), and population growth.
What is the formula for percentage decrease?: To find the new value after a percentage decrease: New Value = Original x (1 - Percentage / 100). Example: $150 with a 20% discount = 150 x 0.80 = $120. To find just the decrease amount: Decrease = Original x (Percentage / 100) = 150 x 0.20 = $30. This formula is used for discounts, depreciation, weight loss targets, and budget cuts.
What is the difference between percentage change and percentage difference?: Percentage change is directional: it measures change from a specific starting (old) value to a new value. Percentage difference is symmetric: it compares two values without implying which came first, using their average as the denominator. Formula: |V1 - V2| / ((|V1| + |V2|) / 2) x 100. Use percentage change for time-series comparisons; use percentage difference for comparing two measurements with no natural baseline.
Why is percentage change not symmetric?: Percentage change depends on the denominator (the old value), so going from 100 to 150 is a +50% change, but going from 150 back to 100 is a -33.3% change. This asymmetry is mathematically correct. To get a symmetric comparison, use percentage difference, which uses the average of both values as the base. Percentage difference for 100 and 150: |50| / 125 x 100 = 40%.
What is a good percentage increase for salary negotiation?: Typical salary increase benchmarks: Cost of living raise = 2-4% (maintains purchasing power). Merit raise = 5-10% (recognizes performance). Promotion = 10-20% (new responsibilities). Job change = 15-30% increase commonly expected for lateral moves. At or above inflation (currently ~3-4%) is needed to avoid a real-money pay cut. Use the % Increase mode: enter your current salary as the original value and the raise percentage to see your new salary instantly.