// measurement · least count 0.01 cm

Vernier Callipers

Drag the slider — or use ← → keys (Shift for 1 mm)
magnified view
Jaw position
Zero error 0.00 cm
View

Close the jaws to inspect zero error, then measure the rod.

How to read a vernier calliper

  1. Least count. The vernier has 10 divisions spanning 9 mm, so each division is 0.9 mm. LC = 1 mm − 0.9 mm = 0.1 mm = 0.01 cm.
  2. Main scale reading (MSR). Find the main-scale mark immediately to the left of the vernier's zero. That value (in cm) is your MSR.
  3. Vernier coincidence (VSD). Exactly one vernier line aligns perfectly with a main-scale line. Its number is the VSD. Use the magnifier!
  4. Observed reading = MSR + VSD × LC.
  5. Zero error. Close the jaws fully. If vernier 0 sits right of main 0, the error is positive: ZE = +VSD × LC. If it sits left, it's negative: ZE = (VSD − 10) × LC.
  6. Corrected reading = observed − ZE (mind the sign — subtracting a negative adds).
💡 In Explore mode, drag the slider and watch the reading panel update live. Arrow keys nudge by one least count.