21 millimeters in feet

Result

The conversion result is: 21 millimeters is equivalent to 0.0688976377952756 feet.^[1]

Conversion formula
How to convert 21 millimeters to feet?

We know (by definition) that: 1 mm ≈ 0.0032808399 ft.

We can set up a proportion to solve for the number of feet.

1 mm / 21 mm ≈ 0.0032808399 ft / x ft

Now, we cross multiply to solve for our unknown x:

x ft ≈ (21 mm / 1 mm) * 0.0032808399 ft → x ft ≈ 0.0688976379 ft

Conclusion:

21 mm ≈ 0.0688976379 ft

Conversion in the opposite direction

The inverse of the conversion factor is that 1 foot is equal to 14.5142857142857 times 21 millimeters.

It can also be expressed as: 21 millimeters is equal to 1 / 14.5142857142857 feet.

Approximation

An approximate numerical result would be: twenty-one millimeters is about zero point zero seven feet, or alternatively, a foot is about fourteen point five zero times twenty-one millimeters.