1/64 inch in decimal and mm
Decimal inches
0.015625 in
0.0156 in to four places
Millimetres
0.396875 mm
From the standard, the international inch, 25.4 mm exactly
The math
- A fraction is its top number divided by its bottom number: 1/64 in = 1 ÷ 64 = 0.015625 in.
- An inch is exactly 25.4 mm, so 0.015625 × 25.4 = 0.396875 mm, or 0.397 mm to three places.
- In feet, divide by 12: 0.015625 ÷ 12 = 0.001302 ft. In centimetres, divide the mm by 10: 0.0396875 cm.
1/64 to the nearest 1/8, 1/16, 1/32
A tape or rule marked more coarsely than 64ths can’t show 1/64 exactly. The nearest marks, and how far off each is (plus means the mark is bigger; a size exactly halfway goes to the bigger mark):
| Nearest | Mark | Off by (in) | Off by (mm) |
|---|---|---|---|
| 1/8 | 0 in | −0.015625 | −0.397 |
| 1/16 | 0 in | −0.015625 | −0.397 |
| 1/32 | 1/32 in | +0.015625 | +0.397 |
Drills, plywood and lumber at 1/64 in
| Drill | Size | Off by |
|---|---|---|
| 0.3 mm | 0.0118 in | −0.0969 mm |
| 0.4 mm | 0.0157 in | +0.0031 mm |
Every drill is on the drill bit size chart.
Sizes either side
| Fraction | Decimal | mm |
|---|---|---|
| 1/32 in | 0.03125 in | 0.794 mm |
Every size is on the fraction to decimal chart; any other size goes in the fraction to decimal calculator.