How to Calculate Percentage Increase
Last updated 2026-09-11
Percentage increase measures how much a value has grown, expressed as a fraction of its starting point — useful for salaries, prices, and performance metrics.
Subtract the old value from the new value
This gives you the raw increase in units.
Divide by the old value
This expresses the increase as a fraction of the starting point.
Multiply by 100
This converts the fraction to a percentage. Full formula: ((New − Old) ÷ Old) × 100.
Example
A salary goes from $50,000 to $56,000. Increase = ((56,000 − 50,000) ÷ 50,000) × 100 = 12%.
Important Considerations
- If the old value is 0, percentage increase is mathematically undefined — there's no baseline to compare against.
- Two successive percentage increases don't add up simply: two 10% increases in a row produce a 21% total increase, not 20%, because the second increase applies to the already-larger value.
- If the new value is smaller than the old one, use percentage decrease instead — the formula direction matters.
Frequently Asked Questions
- Why can't I just add two percentage increases together?
- Because each increase applies to a different base value. A 10% increase followed by another 10% increase compounds: 100 → 110 → 121, a 21% total increase, not 20%.
- What if the value decreased instead?
- Use the percentage decrease formula: ((Old − New) ÷ Old) × 100 — the numerator direction flips.