How to find 30 percent of 40
"Percent" means per hundred, so 30% is the fraction 30/100, or 0.3 as a decimal. Taking 30 percent of 40 means multiplying 40 by that fraction:
30% of 40 = 40 x 30 / 100
= 1,200 / 100
= 12The same answer comes from the decimal form: 40 x 0.3 = 12. And because multiplication is commutative, 30% of 40 equals 40% of 30, which is sometimes the easier way to see it in your head.
Mental math shortcut
10% of 40 is 4 (move the decimal one place left), and 1% is 0.4. Build 30% from those pieces: 3 x 4 = 12.
Nearby percentages of 40
| Percent | Of 40 | 40 minus it | 40 plus it |
|---|---|---|---|
| 1% | 0.4 | 39.6 | 40.4 |
| 5% | 2 | 38 | 42 |
| 10% | 4 | 36 | 44 |
| 15% | 6 | 34 | 46 |
| 20% | 8 | 32 | 48 |
| 25% | 10 | 30 | 50 |
| 29% | 11.6 | 28.4 | 51.6 |
| 31% | 12.4 | 27.6 | 52.4 |
| 35% | 14 | 26 | 54 |
| 50% | 20 | 20 | 60 |
| 60% | 24 | 16 | 64 |
| 75% | 30 | 10 | 70 |
30 percent of other amounts
| Amount | 30% of it |
|---|---|
| 10 | 3 |
| 20 | 6 |
| 25 | 7.5 |
| 30 | 9 |
| 50 | 15 |
| 60 | 18 |
| 75 | 22.5 |
| 80 | 24 |
| 100 | 30 |
| 120 | 36 |
Where this comes up
A 30% discount on a 40 price takes off 12, leaving 28. A 30% tip or tax on 40 adds 12, for a total of 52. If 40 is a score out of a possible total, 30% of it is the share 12 represents. For percent change, reverse percentages, and "X is what percent of Y", use the full percentage calculator.