Guides/Double a number by percent
Double a number by percent
To double a value, multiply by 2 — that is the same as a100% increase (add 100% of the original) or taking200% of the original.
Formulas
- Doubled value = original × 2
- After +100% increase: original × (1 + 1.00) = ×2
- 200% of original = original × 2.00
- “200% increase” usually means +200% → ×3 (triple), not double — language is ambiguous; prefer “doubled” or “+100%.”
Worked examples
- $50 doubled: $100. Percent increase = 100%.
- 120 → 240: 200% of 120; +100% change.
- If someone says “increased 200%” to 240 from 80: 80×3=240 → +200% change (tripled) — clarify wording. See percentage increase.