421 millimeters in inches

Conversion formula
How to convert 421 millimeters to inches?

We know (by definition) that: $1\mathrm{mm}\approx 0.039370079\mathrm{in}$

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

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

Conclusion: 421 ⁢ mm ≈ 16.574803259 ⁢ in

Conversion in the opposite direction

The inverse of the conversion factor is that 1 inch is equal to 0.060332541567696 times 421 millimeters.

It can also be expressed as: 421 millimeters is equal to $\frac{1}{\mathrm{0.060332541567696}}$ inches.

Approximation

An approximate numerical result would be: four hundred and twenty-one millimeters is about sixteen point five seven inches, or alternatively, a inch is about zero point zero six times four hundred and twenty-one millimeters.