Check that the vernier caliper is clean and the jaws are closed
Close the jaws fully and note whether the zero marks align
If the zero marks do not align, record the zero error
Open the jaws and place the object between the outside jaws for external measurement
Gently close the jaws until they touch the object
Lock the slider if needed
Read the main scale value just before the vernier zero
Find the vernier division that exactly matches a main scale mark
Multiply the matching vernier division by the least count
Add the vernier reading to the main scale reading
Apply zero correction if zero error was found
Use the inside jaws for internal measurements
Use the depth rod for depth measurements
Repeat the measurement for accuracy
Return the jaws to zero after use