Mechanical calculator
Bearing Dimensions and Size Converter
Compare the bore, outside diameter and width when the measurements use different units.
How bearing dimensions are listed
Most bearings are listed as inside diameter, outside diameter, then width. An 8 × 40 × 19.05 mm bearing has an 8 mm bore, a 40 mm outside diameter and a width of 19.05 mm.
Common mistakes
- Reversing the inside and outside diameter.
- Calling the width a diameter.
- Measuring a housing, seal or flange instead of the bearing itself.
- Choosing a bearing only because the bore fits the shaft.
This does not select a safe bearing
This page converts and compares dimensions. It does not account for radial load, thrust load, impact, speed, mounting, lubrication, shaft support or bearing life.