Published 20 October 2026 · Updated 24 October 2026
Short answer: percentage increase = (New − Old) ÷ |Old| × 100. Enter any two of the three numbers — old value, new value, or percentage — and this calculator solves the third, showing every step of the working.
% increase = (New − Old) ÷ |Old| × 100. The three steps: find the absolute change (New − Old), scale it by the starting value (divide), convert to percent (× 100). Dividing by the old value is what makes a €200 rise mean very different things on a €2,000 salary (10%) and a €20,000 revenue (1%).
Reverse formulas: New = Old × (1 + %/100) · Old = New ÷ (1 + %/100). Use a negative percent for decreases.
Your salary rises from €2,800 to €3,150:
Reverse check: €2,800 × 1.125 = €3,150 ✓.
1. Percentage points vs percent. A mortgage rate moving from 3% to 4% is a 1 percentage-point rise but a 33% relative increase (1 ÷ 3 × 100). Headlines mix these up constantly — now you can spot it.
2. The asymmetry trap. Up 25% then down 25% does not return to the start: €100 → €125 → €93.75, because the second 25% is taken from a larger base. To undo a 25% rise you need a 20% fall.
Percentage increase = (New − Old) ÷ |Old| × 100. Subtract the old value from the new value, divide by the old value (its size), and multiply by 100.
They use the same formula. Percentage change is the general term for movement in either direction; percentage increase describes the case where the new value is higher.
Moving from 10% to 15% is a 5 percentage-point increase but a 50% relative increase (5 ÷ 10 × 100). Confusing the two is the most common percentage mistake.
Use the same formula: (New − Old) ÷ |Old| × 100. The result comes out negative — for example, €80 down to €72 is −10%, i.e. a 10% decrease.
Yes. A 100% increase doubles a value, 200% triples it, and so on. From €50 to €200 is a 300% increase.
Multiply the original by (1 + percent ÷ 100). A €2,000 salary with a 12.5% raise becomes €2,000 × 1.125 = €2,250.
Divide the new value by (1 + percent ÷ 100). A €138 price after a 15% increase came from €138 ÷ 1.15 = €120.
With zero as the baseline, percentage change is undefined — describe it as an absolute change instead. With a negative baseline, divide by its absolute size, so −50 to −25 is a 50% increase.