Percentage Change Calculator

Use the formula: % Change = ((New Value − Old Value) ÷ |Old Value|) × 100. A positive result is an increase; a negative result is a decrease. Example: from 80 to 100 → ((100 − 80) ÷ 80) × 100 = +25%. Enter both values above for an instant colour-coded result.

The percentage change from 80 to 100 is +25% — a 25% increase. Formula: ((100 − 80) ÷ 80) × 100 = 25. Enter 80 and 100 in the calculator above to confirm.

Use the percentage change formula: ((New Salary − Old Salary) ÷ Old Salary) × 100. Example: salary increased from $55,000 to $60,500 → ((60,500 − 55,000) ÷ 55,000) × 100 = 10% raise. Enter your old and new salary above for an instant result.

The same formula applies as percentage change. If the result is negative, it is a decrease. Example: from $200 to $150 → ((150 − 200) ÷ 200) × 100 = −25%. The calculator colour-codes decreases in red automatically.

Percentage change is directional — it measures how much a value changed from a defined starting point. Percentage difference compares two values symmetrically with no defined start/end, using their average as the base. Use percentage change when you have a "before" and "after" value.

Because percentages are calculated from different base values each time. If you increase $100 by 20% you get $120, then decrease $120 by 20% you get $96 — not $100. The base changes at each step, so equal percentage increases and decreases do not cancel out.

To reverse a percentage change: Original = New Value ÷ (1 + Change%/100) for increases, or Original = New Value ÷ (1 − Change%/100) for decreases. Example: after a 25% increase, the value is 125 → Original = 125 ÷ 1.25 = 100.