Once you've measured your workpiece, you can read the caliper to determine the value of the measurement. There are two sets of graduation's on a vernier caliper. On inch calipers like this one, the main scale is marked in 0.025 inch intervals and is read directly by finding the last graduation passed by the zero mark on the sliding jaw. The vernier scale is located on the sliding jaw. The number of lines is not the same for all calipers, but on most current inch vernier calipers, you'll find 25 graduations. For a final graduation of 0.001 inches. Reading the caliper is a two-step process. First, look at the zero mark on the sliding scale and find the graduation that it last passed. This case, it passed the 5 and then 2 more hash marks. So that's 0.55 inches. To read the vernier scale, note how the lines on the scale match up with the lines on the main scale. The way that the scale is made, only one of these lines will match up correctly. In this case, the 15 matches up correctly. So that's 0.015 inches. The final reading is the sum of these two readings. So that's 0.550 inches and 0.015 inches. For a final reading of 0.565 inches.