Convert Inches Millimeters Calculator

How the answer is presented. The conversion itself is identical in every mode.
Ruler reading only. 16 for a standard tape measure, 32 or 64 for a machinist rule.
Height reading only, when the source unit is feet.
Height reading only, added to the feet above.
Applied to the display value; the exact result is also returned.
Converted value
25.4
Unit Converter
Unrounded result
25.4
Conversion
1 in = 25.4 mm
Reading
25.4 mm
Multiply by
25.4
Reverse conversion
1
Worked out from NIST Special Publication 811, Guide for the Use of the International System of Units and 1 other source.

How this is worked out

2 steps
  1. 1 in = 25.4 mm
  2. 1 x 25.4 = 25.4 mm

Results are general information, not financial, tax, legal, medical or engineering advice.