Common Percentages Cheat Sheet
Most quick percentage math is a handful of friendly percents applied to round numbers. Use this table when you want the answer in your head. For any other pair, including searches like 8.25% of 200, use the percent-of calculator rather than a separate page for each number.
Shortcuts worth memorizing
10% is the number with the decimal point moved one place left. 5% is half of that. 1% is the number divided by 100. 50% is half. 25% is a quarter. 20% is a fifth. 15% is 10% plus 5%.
- 1% of 200 is 2
- 5% of 80 is 4
- 10% of 150 is 15
- 15% of 80 is 12
- 20% of 50 is 10
- 25% of 64 is 16
- 50% of 90 is 45
Common percents of round numbers
Each row is a base amount. Each column is a common percent of that amount. Number queries that are not in this table belong on the percent-of calculator.
| Number | 1% | 5% | 10% | 15% | 20% | 25% | 50% |
|---|---|---|---|---|---|---|---|
| 10 | 0.1 | 0.5 | 1 | 1.5 | 2 | 2.5 | 5 |
| 20 | 0.2 | 1 | 2 | 3 | 4 | 5 | 10 |
| 50 | 0.5 | 2.5 | 5 | 7.5 | 10 | 12.5 | 25 |
| 80 | 0.8 | 4 | 8 | 12 | 16 | 20 | 40 |
| 100 | 1 | 5 | 10 | 15 | 20 | 25 | 50 |
| 200 | 2 | 10 | 20 | 30 | 40 | 50 | 100 |
| 500 | 5 | 25 | 50 | 75 | 100 | 125 | 250 |
| 1000 | 10 | 50 | 100 | 150 | 200 | 250 | 500 |
Building harder percents from easy ones
12% is 10% plus 2%. 2% is double 1%. 7.5% is half of 15%, or 5% plus 2.5%. Once 1%, 5%, and 10% are automatic, most shop and grade percents are additions of those pieces.
Related reading
Mental-math questions
Take 10% and add 5%. 15% of 80 is 8 + 4 = 12.
7.5% is not a column. Half of 15% of 1000 is 75, or use the percent-of calculator for that pair.
Those number queries all use the same formula. This cheat sheet covers friendly percents. Every other pair belongs on one calculator.
Move the decimal point two places left. 1% of 200 is 2. 1% of 80 is 0.8.
Yes, 25% is a quarter of the number. 25% of 64 is 16. Convert other percents to decimals instead of hunting for a matching fraction.