## Conversion formula

The conversion factor from decimeters to millimeters is 100, which means that 1 decimeter is equal to 100 millimeters:

1 dm = 100 mm

To convert 6.4 decimeters into millimeters we have to multiply 6.4 by the conversion factor in order to get the length amount from decimeters to millimeters. We can also form a simple proportion to calculate the result:

1 dm → 100 mm

6.4 dm → L(mm)

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

L(mm) = 6.4 dm × 100 mm

L(mm) = 640 mm

The final result is:

6.4 dm → 640 mm

We conclude that 6.4 decimeters is equivalent to 640 millimeters:

6.4 decimeters = 640 millimeters

## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 millimeter is equal to 0.0015625 × 6.4 decimeters.

Another way is saying that 6.4 decimeters is equal to 1 ÷ 0.0015625 millimeters.

## Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that six point four decimeters is approximately six hundred forty millimeters:

6.4 dm ≅ 640 mm

An alternative is also that one millimeter is approximately zero point zero zero two times six point four decimeters.

## Conversion table

### decimeters to millimeters chart

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

decimeters (dm) millimeters (mm)
7.4 decimeters 740 millimeters
8.4 decimeters 840 millimeters
9.4 decimeters 940 millimeters
10.4 decimeters 1040 millimeters
11.4 decimeters 1140 millimeters
12.4 decimeters 1240 millimeters
13.4 decimeters 1340 millimeters
14.4 decimeters 1440 millimeters
15.4 decimeters 1540 millimeters
16.4 decimeters 1640 millimeters