Millimeter to Thou Converter (and vice versa)

Created by: tinycalcs.com/en
Number of supported units: 2
Last update: 2026

This converter allows you to convert millimeters [mm] to thous [mil] or thous [mil] to millimeters [mm]. Calculations are performed in both directions. The calculation result and the entered value are displayed with up to 20 decimal places for maximum accuracy.

1 millimeter [mm] ≈ 39.3701 thous [mil]1 thou [mil] = 0.0254 millimeters [mm]

Convert millimeters to thous

There are two simple ways to convert millimeters [mm] to thous [mil]. In the first calculation method, the value in millimeters [mm] is divided by 0.0254. The second method multiplies the value in millimeters [mm] by the rounded conversion factor of 39.3701.

  • Thous [mil] = millimeters [mm] ÷ 0.0254
  • Thous [mil] ≈ millimeters [mm] * 39.3701

However, the calculation method with rounded conversion values is only suitable for rough conversions from millimeters [mm] to thous [mil], as rounding errors may occur in the calculation results. The following formula shows another variant that can be used to calculate results as accurately as possible.

  • Thous [mil] = millimeters [mm] ÷ 254 * 104

Convert thous to millimeters

Converting thous [mil] to millimeters [mm] is easy and can be done in two ways. The first method involves multiplication, whereby the value in thous [mil] is multiplied by 0.0254. The second variant is a division. Here, the value in thous [mil] is divided by the rounded conversion factor of 39.3701.

  • Millimeters [mm] = thous [mil] * 0.0254
  • Millimeters [mm] ≈ thous [mil] ÷ 39.3701

However, the version with rounded conversion values can produce somewhat inaccurate calculation results, which is why it is only suitable for rough conversions from thous [mil] to millimeters [mm]. The formula below shows an alternative method that can be used to calculate results as accurately as possible.

  • Millimeters [mm] = thous [mil] * 254 ÷ 104

Converter

Decimal places

How it's calculated

Factor: 
≈ 39.37
Thous = Millimeters ÷ 254 * 104
Millimeters = Thous * 254 ÷ 104

To all available units

Millimeters

Twips

Millimeters

Yards

Millimeters

Yottameters

Millimeters

Zettameters

Nanometers

Ångströms

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