Bearing Life Calculator

Work out bearing life instantly with clear inputs, formula shown and shareable results.

About Bearing Life Calculator

Rolling bearing life follows the cube law L10 = (C/P)³ million revolutions, the life that 90 percent of identical bearings will reach. Because the exponent is three, halving the load multiplies life eightfold, which is why a modest reduction in load or a size increase transforms bearing life.

Formulas

Basic rating life

L10 = (C / P)³ million revolutions

Life in hours

L10h = L10 x 10^6 / (60 x rpm)

Worked example

With the default values below, Bearing Life Calculator returns L10 life of 1,190. Change any input above and every figure here is recalculated in your browser.

Inputs used

Basic dynamic capacity Cminimum 1 lbf: 6,000 lbf
Equivalent load Pminimum 1 lbf: 1,200 lbf
Operating speedminimum 1 rpm: 1,750 rpm

Results

L10 life: 1,190 h
L10 in million revolutions: 125.0 Mrev
Years at 8 hours a day: 0.4 years
Capacity to load ratio: 5.00

Step by step

1Values used
2Basic rating life
3Life in hours
4L10 life= 1,190 h
5L10 in million revolutions= 125.0 Mrev
6Years at 8 hours a day= 0.4 years
7Capacity to load ratio= 5.00

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Preliminary estimate only. Actual life depends on lubrication, contamination, alignment and temperature; consult the bearing manufacturer for adjusted life ratings.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Actual life depends on lubrication, contamination, alignment and temperature; consult the bearing manufacturer for adjusted life ratings.

Frequently Asked Questions

How is the Bearing Life figure worked out?

L10 = (C / P)³ million revolutions. Rolling bearing life follows the cube law L10 = (C/P)³ million revolutions, the life that 90 percent of identical bearings will reach.

Why is it called L10?

It is the tenth percentile of the failure distribution: 90 percent of bearings survive it. Median life is roughly five times longer, so L10 is deliberately conservative.

What values do I need to enter?

This calculator takes 3 inputs: Basic dynamic capacity C, Equivalent load P, Operating speed. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.