Accuracy and Calibration of Calipers
This unit of the Metrology Fundamentals series was developed by the Mitutoyo Institute of Metrology, the educational department within
Mitutoyo America Corporation. The Mitutoyo Institute of Metrology provides educational courses, free on-demand training videos, and
other resources across a wide variety of measurement related topics including basic inspection techniques, principles of dimensional
metrology, calibration methods, and GD&T. For more information on the educational opportunities available from Mitutoyo America
Corporation, visit us at www.mitutoyo.com/education.
This technical bulletin addresses the accuracy and calibration of digital, dial, and vernier calipers. The technical basis for
this document is the American national standard (ANSI standard) entitled ASME B89.1.14-2018. This technical bulletin
summarizes the most important technical issues; however, the ASME standard should be consulted for further information.
Accuracy Specifications
Two accuracy specifications cover the most important metrological characteristics of calipers. In accordance to the ASME
standard, as well as the international standard ISO 13385-1, these two characteristics are called the partial surface contact
error, E, and the scale shift error, S. The partial surface contact error applies to any measurements made using the outside
measuring faces, and the scale shift error applies to measurements using any other measuring faces available on the caliper,
such as inside, step, and depth measurement. The key difference is that all specifications apply when the zero is set using
the outside measuring faces and therefore there is the possibility of larger errors when using the other measuring faces.
The table below lists the default specification values that are in the ASME B89.1.14 standard. These specifications are stated
as maximum permissible errors, or MPE values, for the E and S errors. These values are only defaults the manufacturer
or user may state different values. Mitutoyo generally states values that are equal to or less than the values shown in this
table. Mitutoyo specifications for calipers are quite similar to these values, and many customers may find the best practice
is to simply adopt theses values for their own caliper calibrations.
Digital Resolution / Dial or Vernier Scale Interval
Measured Length, L
0.0005 in. 0.001 in. 0.01 mm 0.02 mm 0.05 mm
EMPE SMPE EMPE SMPE EMPE SMPE EMPE SMPE EMPE SMPE
mm in.
in. in. in. in mm mm mm mm mm mm
0 L 50 0 L 2 ± 0.0010 ± 0.0010 ± 0.001 ± 0.001 ± 0.02 ± 0.03 ± 0.02 ± 0.04 ± 0.05 ± 0.05
50 L 100 2 L 4 ± 0.0010 ± 0.0020 ± 0.001 ± 0.002 ± 0.03 ± 0.05 ± 0.04 ± 0.06 ± 0.05 ± 0.10
100 L 150 4 L 6 ± 0.0010 ± 0.0020 ± 0.001 ± 0.002 ± 0.03 ± 0.05 ± 0.04 ± 0.06 ± 0.10 ± 0.10
150 L 200 6 L 8 ± 0.0015 ± 0.0020 ± 0.002 ± 0.003 ± 0.03 ± 0.05 ± 0.04 ± 0.06 ± 0.10 ± 0.10
200 L 300 8 L 12 ± 0.0015 ± 0.0025 ± 0.002 ± 0.003 ± 0.04 ± 0.06 ± 0.04 ± 0.06 ± 0.10 ± 0.10
300 L 400 12 L 16 ± 0.0020 ± 0.0025 ± 0.002 ± 0.003 ± 0.04 ± 0.06 ± 0.04 ± 0.06 ± 0.10 ± 0.10
400 L 500 16 L 20 ± 0.0020 ± 0.0030 ± 0.002 ± 0.003 ± 0.05 ± 0.07 ± 0.06 ± 0.08 ± 0.10 ± 0.10
500 L 600 20 L 24 ± 0.0020 ± 0.0030 ± 0.002 ± 0.003 ± 0.05 ± 0.07 ± 0.06 ± 0.08 ± 0.15 ± 0.15
600 L 700 24 L 28 ± 0.0025 ± 0.0035 ± 0.003 ± 0.004 ± 0.06 ± 0.08 ± 0.06 ± 0.08 ± 0.15 ± 0.15
700 L 800 28 L 32 ± 0.0025 ± 0.0035 ± 0.003 ± 0.004 ± 0.06 ± 0.08 ± 0.06 ± 0.08 ± 0.15 ± 0.15
800 L 1000 32 L 40 ± 0.0030 ± 0.0040 ± 0.003 ± 0.004 ± 0.07 ± 0.09 ± 0.08 ± 0.10 ± 0.15 ± 0.15
For complete definitions of EMPE and SMPE please see the ASME B89.1.14-2018 standard.
These specifications are a function of the measured length, L, not the overall measuring range of the caliper.
The decision rule that applies for these specifications is Simple Acceptance with a test uncertainty ratio, TUR 4.
All specifications apply at 20 C.
EDU-15003A
© 2018 Mitutoyo America Corporation
