Sumwise

What is 30 Percent of 42?

30% of 42 = 12.6

Result
12.6
Remaining
29.4
30% as decimal
0.3
42 + 30%
54.6

Sumwise · Maintained by Theo Abbott (pen name) · automated checks · Data: exact arithmetic; unit definitions from NIST SP 811 · Updated · How the checks work

How to work it out

  1. Turn the percentage into a decimal: 30 ÷ 100 = 0.3
  2. Multiply: 0.3 × 42 = 12.6
  3. Check: Work backwards: 12.6 ÷ 42 × 100 = 30%.

Another method. As a proportion of part to whole: 30/100 = part/42, so part = 30 × 42 ÷ 100 = 12.6. Both methods always give the same answer.

In a spreadsheet: =30%*42. Forgetting to divide the percentage by 100 makes the answer 100 times too big. Note that x% of y always equals y% of x.

What the result means

12.6 is the 30% share of 42. The remaining 70% is 29.4, and the two parts add back up to 42.

Discounts: 30% off an item priced $42 saves $12.6, so you pay $29.4.

Adding and taking away 30%

Increasing 42 by 30% gives 54.6 and decreasing it by 30% gives 29.4. These do not cancel out: raising 42 by 30% and then lowering the result by 30% ends at 38.22, because the second 30% is taken of a bigger number.

Related results

Results for nearby numbers
5% of 42

5% of 42 = 2.1

10% of 42

10% of 42 = 4.2

15% of 42

15% of 42 = 6.3

20% of 42

20% of 42 = 8.4

25% of 42

25% of 42 = 10.5

50% of 42

50% of 42 = 21

75% of 42

75% of 42 = 31.5

The other way round: 42% of 30. 30% of 42 and 42% of 30 are always equal (both are 30 × 42 ÷ 100 = 12.6), so you can swap the numbers when one order is easier to work out in your head.

Practice

6% of 19
Show answer

6% of 19 = 1.14

83% of 56
Show answer

83% of 56 = 46.48

50% of 46
Show answer

50% of 46 = 23

71% of 37
Show answer

71% of 37 = 26.27

30% of 31
Show answer

30% of 31 = 9.3

37% of 93
Show answer

37% of 93 = 34.41

Calculate another

How answers are calculated and checked: methodology.

Questions

What is 30 Percent of 42?

30% of 42 is 12.6. Formula, steps and practice examples.

What is 30% off 42?

29.4. Taking 30% off leaves 70% of 42.

What is 42 plus 30%?

54.6. Adding 30% is the same as multiplying by 1.3.