If you need to quickly find out the millimeter equivalent to a measurement in inches, you can do so by using an automatic conversions website.
Inches to Millimeters formula 0.
How to use a ruler This ruler measure in two different units of length, inches on one side English ruler and centimeters on the other side metric ruler.
In order to accurately measure the length of your item, we strongly recommend that you first, set the correct pixels per inch to your own device, after adjustment, you will have the most precise ruler online.
Though traditional standards for the exact length of an inch have varied, it is equal to exactly 25.
Note: For a pure decimal result please select 'decimal' from the options above the result.
Conclusion Above all discussion was about the Online Ruler, how to calibrate to actual size, and how to measure any object using it.
It indicates one thousandth of the base unit, in this case the meter.