Bearing Life Calculator

Find the basic rating life of a rolling bearing from its dynamic load rating C, the equivalent load P and the speed, as in ISO 281. Then see the life at a higher reliability and the rating you need for a target life.

Bearing and load

Take C, X and Y from the bearing maker's table. For a deep groove ball bearing with little axial load (Fa/Fr at or below the factor e), X = 1 and Y = 0.

Results

Basic rating life L10h:

Equivalent load P
Load ratio C/P
L10 in revolutions
Life at the chosen reliability
Rating needed for the target life
Target life met?

P = X·Fr + Y·Fa. L10 = (C/P)p million revolutions. L10h = 106/(60·n) × L10. Ln = a1 × L10, with a1 from ISO 281.

This is the basic rating life: 90% of a large group of identical bearings reach it. It leaves out the ISO 281 life modification factor for lubrication and contamination, which can raise or lower the life a lot. Use the maker's calculator for a final check.

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Life at other loads, same bearing and speed

Load P, kNC/PL10, million revL10h, hours