## Conversion formula

The conversion factor from inches to millimeters is 25.4, which means that 1 inch is equal to 25.4 millimeters:

1 in = 25.4 mm

To convert 12 inches into millimeters we have to multiply 12 by the conversion factor in order to get the length amount from inches to millimeters. We can also form a simple proportion to calculate the result:

1 in → 25.4 mm

12 in → L(mm)

Solve the above proportion to obtain the length L in millimeters:

L(mm) = 12 in × 25.4 mm

L(mm) = 304.8 mm

The final result is:

12 in → 304.8 mm

We conclude that 12 inches is equivalent to 304.8 millimeters:

12 inches = 304.8 millimeters ## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 millimeter is equal to 0.0032808398950131 × 12 inches.

Another way is saying that 12 inches is equal to 1 ÷ 0.0032808398950131 millimeters.

## Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twelve inches is approximately three hundred four point eight millimeters:

12 in ≅ 304.8 mm

An alternative is also that one millimeter is approximately zero point zero zero three times twelve inches.

## Conversion table

### inches to millimeters chart

For quick reference purposes, below is the conversion table you can use to convert from inches to millimeters

inches (in) millimeters (mm)
13 inches 330.2 millimeters
14 inches 355.6 millimeters
15 inches 381 millimeters
16 inches 406.4 millimeters
17 inches 431.8 millimeters
18 inches 457.2 millimeters
19 inches 482.6 millimeters
20 inches 508 millimeters
21 inches 533.4 millimeters
22 inches 558.8 millimeters