21/64 as a decimal
21/64 = 0.328125 inches = 8.3344 mm.
0.328125
21/64 of an inch
Millimetres
8.3344 mm
Centimetres
0.83344 cm
Percent
32.8125%
Decimal
terminates
64 goes into 21 0 times with 21 left over, so write 0 and a decimal point. Then bring down a zero and divide again, one digit at a time.
| Step | Divide | Digit | Subtract | Remainder |
|---|---|---|---|---|
| 1 | 210 ÷ 64 | 3 | 210 − 192 | 18 |
| 2 | 180 ÷ 64 | 2 | 180 − 128 | 52 |
| 3 | 520 ÷ 64 | 8 | 520 − 512 | 8 |
| 4 | 80 ÷ 64 | 1 | 80 − 64 | 16 |
| 5 | 160 ÷ 64 | 2 | 160 − 128 | 32 |
| 6 | 320 ÷ 64 | 5 | 320 − 320 | 0 |
Remainder 0: nothing is left to divide, so the division stops and 21/64 = 0.328125 exactly.
Where 21/64 falls at each precision, and whether the mark is the value exactly
| Rule | Nearest mark | Exact? |
|---|---|---|
| 1/16 | 5/16 | nearest |
| 1/32 | 11/32 | nearest |
| 1/64 | 21/64 | exact |
Mixed numbers with 21/64
A whole number of inches plus 21/64: the whole number goes in front of the decimal point and 21/64 supplies the digits after it
| Mixed | Inches | mm |
|---|---|---|
| 1 21/64 | 1.328125 | 33.7344 |
| 2 21/64 | 2.328125 | 59.1344 |
| 3 21/64 | 3.328125 | 84.5344 |
| 4 21/64 | 4.328125 | 109.9344 |
| 5 21/64 | 5.328125 | 135.3344 |
| 6 21/64 | 6.328125 | 160.7344 |
| 7 21/64 | 7.328125 | 186.1344 |
| 8 21/64 | 8.328125 | 211.5344 |
| 9 21/64 | 9.328125 | 236.9344 |
| 10 21/64 | 10.328125 | 262.3344 |
| 11 21/64 | 11.328125 | 287.7344 |
| 12 21/64 | 12.328125 | 313.1344 |
Converting 21/64 to a decimal
A fraction is a division. 21/64 = 21 ÷ 64 = 0.328125. The decimal terminates because 64 factors into 2 × 2 × 2 × 2 × 2 × 2 — only 2s and 5s, the factors of ten. Any fraction whose denominator is built from those has an exact decimal.
In metric that is 8.3344 millimetres (0.83344 cm), since one inch is exactly 25.4 mm. As a percentage of an inch it is 32.8125%.
21/64 is a real mark on a rule: it is the 21/64 mark on a 1/64 rule.
Going the other way
To turn 0.328125 back into a fraction, pick the precision you are working to and multiply. At 1/16: 0.328125 × 16 = 5.25, giving 5/16 after rounding to the nearest mark. At 1/32: 0.328125 × 32 = 10.5, giving 11/32 after rounding to the nearest mark. At 1/64: 0.328125 × 64 = 21, giving 21/64 exactly.
What is 21/64 as a decimal?
21/64 as a decimal is 0.328125. Divide the numerator by the denominator: 21 ÷ 64 = 0.328125. The division comes out exactly, with no remainder left over.
What is 2 21/64 as a decimal?
2 21/64 as a decimal is 2.328125. The whole number stays in front of the decimal point and 21/64 supplies the digits after it, so 2 21/64 = 2 + 0.328125. In millimetres that is 59.1344 mm. This page's mixed-numbers table runs from 1 21/64 to 12 21/64.
What is 21/64 as a percent?
21/64 as a percent is 32.8125%. Multiply the decimal by 100: 0.328125 × 100 = 32.8125%.
What is 0.328125 as a fraction?
0.328125 as a fraction is 21/64, in lowest terms.
How many millimetres is 21/64 of an inch?
21/64 of an inch is 8.3344 mm, or 0.83344 cm. An inch has been defined as exactly 25.4 mm since 1959, so this conversion is a definition rather than a measurement — the millimetre value is exact too.
Where is 21/64 on a tape measure?
21/64 is a real mark on a rule: it is the 21/64 mark on a 1/64 rule.