1 mm to inches

Instant conversion for 1 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.

1mm to inches conversion

Decimal inches
0.0394
Nearest 1/64
3/64 in (+0.191 mm)

The inches fraction result is rounded to the nearest 1/64 fraction.

1 millimeter is equal to 0.0394 inches.

  • Decimal inches: 0.0394 in
  • Nearest 1/64: 3/64 in (+0.191 mm from the exact size)

How many inches is 1mm?

1 millimeter is equal to 0.0394 inches. That is the exact international conversion ( 1 in = 25.4 mm). On a fractional chart, the nearest 1/64 is 3/64 in.

How to convert 1mm to inches

Formula: inches = millimeters ÷ 25.4 (exact). Or multiply by 0.0393701 for a quick estimate of the same definition.

  1. Start with 1 mm.
  2. Divide by 25.4: 1 ÷ 25.4 = 0.0394 in.
  3. Reverse check: 0.0394 × 25.4 = 1 — 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, 1 mm = 0.0394 in exactly, while 3/64 in differs by +0.191 mm. The converter disclaimer (“rounded to the nearest 1/64 fraction”) exists so that difference is never mistaken for a data error.

Is 1 mm the same as 1/32 inch?

No. 1/32 in equals 0.79375 mm — about 0.206 mm smaller than 1 mm. On a 1/64 chart the nearest tick is 3/64 in (1.190625 mm), about 0.191 mm larger than 1 mm. In decimal inches 1 mm is 0.0394 in, or roughly 39.37 thousandths of an inch (thou/mil). For a thickness feel: about ten sheets of typical copy paper stack near 1 mm; a credit card (roughly 0.76 mm) is a bit thinner. Tiny clearances like this rarely land on a clean imperial tick.

Compared with 1/32 in (0.794 mm): 1/32 in is about 0.206 mm smaller than 1 mm.

Nearest inch fractions

Same conversion engine as the calculator. Diff (mm) is how far each size sits from exact 1 mm (positive = larger than 1 mm; negative = smaller).

ComparisonInchesmmDiff (mm)
Exact0.03941
Thou / mil39.37 thou1
Nearest 1/643/641.191+0.191
Nearest 1/321/320.794-0.206
Often confused1/161.588+0.587

This page is for tiny clearances and thickness checks — not body measurements. For the full mm chart, see the mm to inches hub.

1mm to inches conversion chart

Local density around 1 mm (±1 mm, every 0.1 mm). For the full 0–100 mm table, use the mm to inches hub chart.

mminches (decimal)inches (nearest 1/64)
0.10.00390
0.20.00791/64
0.30.01181/64
0.40.01571/64
0.50.01971/64
0.60.02361/32
0.70.02761/32
0.80.03151/32
0.90.03541/32
10.03943/64
1.10.04333/64
1.20.04723/64
1.30.05123/64
1.40.05511/16
1.50.05911/16
1.60.06301/16
1.70.06691/16
1.80.07095/64
1.90.07485/64
20.07875/64

FAQ

  • How many inches is 1 mm?

    1 millimeter is equal to 0.0394 inches (1 ÷ 25.4). That is about 39.37 thousandths of an inch (thou/mil).

  • What fraction of an inch is 1 mm?

    The nearest 1/64 is 3/64 in (1.191 mm), about 0.191 mm larger than exact 1 mm. The nearest 1/32 is 1/32 in (0.794 mm), about 0.206 mm smaller than 1 mm.

  • Is 1 mm the same as 1/32 inch?

    No. 1/32 in = 0.79375 mm, about 0.206 mm smaller than 1 mm. On a 1/64 chart the closer tick is 3/64 in, about 0.191 mm larger than 1 mm.

  • How many mils / thou is 1 mm?

    1 mm = 0.03937007874 in × 1000 ≈ 39.37 thou (mils). One thou is 0.001 in = 0.0254 mm.

  • How thick is 1 mm?

    1 mm is 0.0394 in. Roughly ten sheets of typical copy paper stack near 1 mm; a credit card (about 0.76 mm) is a bit thinner. It is not equal to 1/32 in.

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