1/3 as a Percent

How to convert 1/3 to a percent

1. Divide the top number by the bottom number: 1 ÷ 3 = 0.3333….
2. Multiply by 100: 0.3333 × 100 = 33.33%.

Because 3 has a prime factor other than 2 or 5, the decimal never ends. That is why the percent is shown rounded to two decimal places, which is what most teachers and textbooks expect.

Where you will see 1/3

One third of a cup is a standard US measuring cup, about 79 mL, and it is 33.33% of a full cup.

One third of a day is 8 hours, the amount of sleep often recommended for adults.

How 1/3 compares with nearby fractions

1/3 (33.33%) is a little more than 1/4 (25%) and a little less than 3/8 (37.5%). This is handy for estimating: if you remember the nearby benchmark, you can check that your answer is in the right range before you rely on it.

Check it in reverse

To go from the percent back to the fraction, write 33.33% over 100 (using the exact value rather than the rounded one) and simplify. Because the decimal repeats, 33.33% is a rounded figure; multiplying it back by 3 gives about 1, which rounds to 1.

1/3 of common amounts

Knowing that 1/3 is 33.33% lets you take that share of any number:

• 1/3 of 20 = 6.67
• 1/3 of 50 = 16.67
• 1/3 of 80 = 26.67
• 1/3 of 200 = 66.67

All the thirds as percents

Other fractions as percents

• 6/7
• 1/8
• 1/6
• 4/5
• 3/5
• 3/2
• 5/8
• 5/4
• 5 1/5
• 2/5
• 1/5
• 4 3/4
• 4 1/4
• 3/8
• 1/4
• 5/7