Reading a vernier scale

Perhaps it would be best to look at a real vernier calipers first. The one in this animation is rather unusual, but the principle for making a reading is the same.

Showing the reading principle

This applet shows how one interprets the vernier scale on a calipers.

NOTE on most screens the picture will be quite magnified! So it looks about 3 to 4 times bigger than real millimeters.


Put a check in the   show box (by clicking with the mouse) and draging  left/right on the movable jaw. Then you will see that small arrows show which gradation lines on the scales are lined up and how this gives the  1/10th mm value on the lower scale.

Reading exercise

Take away the check in the   show box. Move the jaw and write in your measurement in      mm

Use .  as decimal sign! When you press [Enter] you are told how well you did.


There is a QBASIC training program that shows more step by step how each reading is done. It also shows more types of scale division. It is easily downloaded (only 0,2 Mb) here: (zipped or self-extracting). Even QBasic is included so it is ready to run. (The text in these may be in Swedish. I have English versions that I can find or recreate and make available if you contact me.) 

1 Pictures of a real calipers being used  | 2 Simulation showing how to use a (vernier or digital) caliper