0.25 inches to millimeters
6.35 mm
0.25 in = 6.35 mm.
millimeters
6.35mm
0.25 in = 6.35 mm
In short
How many millimeters is 0.25 inches?
0.25 in = 6.35 mm. 1 inch = 25.400000 millimeters, so the working is 0.25 × 25.400000 = 6.35.
The working
The factor below is an exact definition rather than a measurement, so nothing is approximated in the arithmetic. The only rounding on this page happens where a number is displayed.
1 inch = 25.400000 millimeters 0.25 × 25.400000 = 6.35
How much precision do you need?
Each row is the same answer cut at a different number of decimals, with what that choice costs you. Pick the shortest row whose error is smaller than whatever you are measuring with.
| Rounded to | Answer (mm) | Off by |
|---|---|---|
| Whole number | 6 | −0.35000 |
| 1 decimal | 6.3 | −0.05000 |
| 2 decimals | 6.35 | exact |
Round trip: take 6.35 mm back the other way and you land on 0.2500 in — a drift of 0.0000 in. That gap is the rounding, not the conversion.
Frequently asked questions
What is 0.25 inches in millimeters?
0.25 inches is 6.35 millimeters. 1 inch = 25.400000 millimeters, so the working is 0.25 × 25.400000 = 6.35.
How accurate is 6.35 mm?
Rounding to 6.35 mm and converting straight back gives 0.2500 in, a drift of 0.0000 in from the 0.25 you started with. The factor itself is exact; every bit of that difference comes from the rounding, not the conversion.
Nearby values
Any value at all
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