40 millimeters to inches
1.57 in
40 mm = 1.57 in.
inches
1.57in
40 mm = 1.57 in
In short
How many inches is 40 millimeters?
40 mm = 1.57 in. 1 millimeter = 0.039370 inches, so the working is 40 × 0.039370 = 1.57.
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 millimeter = 0.039370 inches 40 × 0.039370 = 1.57
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 (in) | Off by |
|---|---|---|
| Whole number | 2 | +0.42520 |
| 1 decimal | 1.6 | +0.02520 |
| 2 decimals | 1.57 | −0.00480 |
Round trip: take 1.57 in back the other way and you land on 39.8780 mm — a drift of 0.1220 mm. That gap is the rounding, not the conversion.
What 40 mm looks like
42.67 mm
The R&A and the USGA require a golf ball to be at least 42.67 mm in diameter.
Frequently asked questions
What is 40 millimeters in inches?
40 millimeters is 1.57 inches. 1 millimeter = 0.039370 inches, so the working is 40 × 0.039370 = 1.57.
How accurate is 1.57 in?
Rounding to 1.57 in and converting straight back gives 39.8780 mm, a drift of 0.1220 mm from the 40 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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