10 mm to inches
Instant conversion for 10 mm — decimal inches, the nearest 1/64 fraction , and how far off common imperial sizes are, using the same engine as the mm to inches hub.
10mm to inches conversion
- Decimal inches
- 0.3937
- Nearest 1/64
- 25/64 in (−0.078 mm)
- Feet + inches
- 0 ft 0.394 in
The inches fraction result is rounded to the nearest 1/64 fraction.
10 millimeters is equal to 0.3937 inches.
- Decimal inches: 0.3937 in
- Nearest 1/64: 25/64 in (-0.078 mm from the exact size)
How many inches is 10mm?
10 millimeters is equal to 0.3937 inches. That is the exact international conversion ( 1 in = 25.4 mm). On a fractional chart, the nearest 1/64 is 25/64 in.
How to convert 10mm to inches
Formula: inches = millimeters ÷ 25.4 (exact). Or multiply by 0.0393701 for a quick estimate of the same definition.
- Start with 10 mm.
- Divide by 25.4: 10 ÷ 25.4 = 0.3937 in.
- Reverse check: 0.3937 × 25.4 = 10 — the conversion round-trips cleanly.
About the fraction result
The decimal column is exact (shown to four places). The fraction is the nearest 1/64 approximation used on rulers and bit charts — so the two can disagree. Here, 10 mm = 0.3937 in exactly, while 25/64 in differs by -0.078 mm. The converter disclaimer (“rounded to the nearest 1/64 fraction”) exists so that difference is never mistaken for a data error.
10 mm in fractional inches (bits & sockets)
10 mm is a common small metric drill bit and socket size. The nearest 1/64 is 25/64 in — slightly undersize versus the exact decimal. People often reach for 3/8 in instead, but that is a different size.
Compared with 3/8 in (9.52 mm): 10 mm is +0.475 mm (metric size is larger).
This page is for specification checks — drill bits, sockets, tubing, and stock — not body measurements. For shop picks across many metric diameters, see the drill bit & socket mm to inches chart.
10mm to inches conversion chart
Local density around 10 mm (±1 mm, every 0.1 mm). For the full 0–100 mm table, use the mm to inches hub chart.
| mm | inches (decimal) | inches (nearest 1/64) |
|---|---|---|
| 9 | 0.3543 | 23/64 |
| 9.1 | 0.3583 | 23/64 |
| 9.2 | 0.3622 | 23/64 |
| 9.3 | 0.3661 | 23/64 |
| 9.4 | 0.3701 | 3/8 |
| 9.5 | 0.3740 | 3/8 |
| 9.6 | 0.3780 | 3/8 |
| 9.7 | 0.3819 | 3/8 |
| 9.8 | 0.3858 | 25/64 |
| 9.9 | 0.3898 | 25/64 |
| 10 | 0.3937 | 25/64 |
| 10.1 | 0.3976 | 25/64 |
| 10.2 | 0.4016 | 13/32 |
| 10.3 | 0.4055 | 13/32 |
| 10.4 | 0.4094 | 13/32 |
| 10.5 | 0.4134 | 13/32 |
| 10.6 | 0.4173 | 27/64 |
| 10.7 | 0.4213 | 27/64 |
| 10.8 | 0.4252 | 27/64 |
| 10.9 | 0.4291 | 27/64 |
| 11 | 0.4331 | 7/16 |
FAQ
How many inches is 10 mm?
10 millimeters is equal to 0.3937 inches.
What fraction of an inch is 10 mm?
The nearest 1/64 is 25/64 in (0.390625 in), about 0.08 mm undersize versus exact 10 mm.
Is 10 mm the same as 3/8 inch?
No. 3/8 in = 9.525 mm, so 10 mm is 0.475 mm larger. Prefer a true 10 mm bit or socket when fit matters.