Guides/What is 20% of a number

What is 20 percent of a number?

Twenty percent means twenty parts out of one hundred — or one-fifth. The fastest path is multiply by 0.20 (or divide by 5).

Formula

20% of N = N × 0.20 = N ÷ 5

General rule: X% of N = N × (X ÷ 100).

Mental shortcuts near 20%

• 10%: move the decimal one place left (250 → 25).
• 20%: double 10%, or divide by 5.
• 15%: 10% + half of 10%.
• 25%: divide by 4.

Worked examples

1. 20% of 50: 50 × 0.2 = 10.
2. 20% of 85: 85 ÷ 5 = 17.
3. 20% of $49.99: ≈ 0.2 × 49.99 = $10.00 (sale savings on a 20% off tag).
4. 20% tip on $64: 0.2 × 64 = $12.80.
5. Score: 20% of 200 points = 40.
6. Not the same as reverse: if a sale price is already 20% off, recovering the original uses ÷ 0.80 — seeoriginal before discount.

Common mistakes

• Multiplying by 20 instead of 0.20.
• Confusing “20% of N” with “N is 20% of what?” (that needs ÷ 0.20).
• Stacking percents as if 20% + 10% off always equals 30% off the original.

Try it free

Use thePercentage Calculator“X% of Y” tab. Broader walkthrough:percentage of a number.