How to find 90 percent of 80
"Percent" means per hundred, so 90% is the fraction 90/100, or 0.9 as a decimal. Taking 90 percent of 80 means multiplying 80 by that fraction:
90% of 80 = 80 x 90 / 100
= 7,200 / 100
= 72The same answer comes from the decimal form: 80 x 0.9 = 72. And because multiplication is commutative, 90% of 80 equals 80% of 90, which is sometimes the easier way to see it in your head.
Mental math shortcut
10% of 80 is 8 (move the decimal one place left), and 1% is 0.8. Build 90% from those pieces: 9 x 8 = 72.
Nearby percentages of 80
| Percent | Of 80 | 80 minus it | 80 plus it |
|---|---|---|---|
| 1% | 0.8 | 79.2 | 80.8 |
| 5% | 4 | 76 | 84 |
| 10% | 8 | 72 | 88 |
| 15% | 12 | 68 | 92 |
| 20% | 16 | 64 | 96 |
| 25% | 20 | 60 | 100 |
| 30% | 24 | 56 | 104 |
| 50% | 40 | 40 | 120 |
| 75% | 60 | 20 | 140 |
| 85% | 68 | 12 | 148 |
| 89% | 71.2 | 8.8 | 151.2 |
| 91% | 72.8 | 7.2 | 152.8 |
90 percent of other amounts
| Amount | 90% of it |
|---|---|
| 20 | 18 |
| 25 | 22.5 |
| 30 | 27 |
| 40 | 36 |
| 50 | 45 |
| 60 | 54 |
| 75 | 67.5 |
| 100 | 90 |
| 120 | 108 |
| 150 | 135 |
Where this comes up
A 90% discount on a 80 price takes off 72, leaving 8. A 90% tip or tax on 80 adds 72, for a total of 152. If 80 is a score out of a possible total, 90% of it is the share 72 represents. For percent change, reverse percentages, and "X is what percent of Y", use the full percentage calculator.