Fractional Inches to Decimal Inches to Approximate Millimeters to Practical Millimeters
Decimal inches multiplied by 25.4 = approximate mm. N.B. When specifying metric sheet or trim sizes, fractional approximate mm measurements must be rounded off to the nearest whole number; i.e., 50.8 mm is not a practical measurement; it should be rounded up to 51 mm, and 0.5 mm is always rounded down.
| Fractional Inch |
Decimal Inch |
Approximate Millimeters |
Practical Millimeters |
|---|---|---|---|
| 1/16 | 0.0625 | 1.5875 | 2 |
| 1/8 | 0.1250 | 3.1750 | 3 |
| 3/16 | 0.1875 | 4.7625 | 5 |
| 1/4 | 0.2500 | 6.3500 | 6 |
| 5/16 | 0.3125 | 7.9375 | 8 |
| 3/8 | 0.3750 | 9.5250 | 10 |
| 7/16 | 0.4375 | 11.1125 | 11 |
| 1/2 | 0.5000 | 12.7000 | 13 |
| 9/16 | 0.5625 | 14.2875 | 14 |
| 5/8 | 0.6250 | 15.8750 | 16 |
| 11/16 | 0.6875 | 17.4625 | 17 |
| 3/4 | 0.7500 | 19.0500 | 19 |
| 13/16 | 0.8125 | 20.6375 | 21 |
| 7/8 | 0.8750 | 22.2250 | 22 |
| 15/16 | 0.9375 | 23.8125 | 24 |
| 1.0 | 1.0 | 25.4 | 25 |
Millimeters to Decimal Inches to Approximate Fractional Inches to Practical Fractional Inches
Millimeters divided by 25.4 = decimal inches. N.B. Fractional practical inches have been rounded to the nearest 1/16 inch, which may not always be a practical measurement when specifying sheet or trim sizes in inches. "<" = less than; ">" = greater than
| Millimeters | Decimal Inch |
Approximate Fractional Inch |
Practical Fractional Inch |
|---|---|---|---|
| 1 | 0.03937 | <3/64 | 0 |
| 2 | 0.07874 | >5/64 | 1/16 |
| 3 | 0.11811 | >7/64 | 1/8 |
| 4 | 0.15748 | >5/32 | 3/16 |
| 5 | 0.19685 | <13/64 | 3/16 |
| 6 | 0.23622 | >15/64 | 1/4 |
| 7 | 0.27559 | <9/32 | 1/4 |
| 8 | 0.31496 | >5/16 | 5/16 |
| 9 | 0.35433 | >11/32 | 3/8 |
| 10 | 0.39370 | <13/32 | 3/8 |
| 11 | 0.43307 | >27/64 | 7/16 |
| 12 | 0.47244 | >15/32 | 1/2 |
| 13 | 0.51181 | <33/64 | 1/2 |
| 14 | 0.55118 | >35/64 | 9/16 |
| 15 | 0.59055 | <19/32 | 9/16 |
| 16 | 0.62992 | <41/64 | 5/8 |
| 17 | 0.66929 | >21/32 | 11/16 |
| 18 | 0.70866 | <23/32 | 11/16 |
| 19 | 0.74803 | >47/64 | 3/4 |
| 20 | 0.78740 | >25/32 | 13/16 |
| 21 | 0.82677 | <53/64 | 13/16 |
| 22 | 0.86614 | >55/64 | 7/8 |
| 23 | 0.90551 | <29/32 | 7/8 |
| 24 | 0.94488 | <61/64 | 15/16 |
| 25 | 0.98425 | >31/32 | 1 |