Bearing Life Calculator

Bearing life falls with the cube of the load: a ball bearing rated C = 30 kN under 5 kN at 1000 rpm lasts L10h = 3600 h.

Bearing:

Ball (k = 3)Roller (k = 10/3)

Dynamic load rating C (kN):

Radial load Fr (kN):

Axial load Fa (kN):

Radial factor X:

Thrust factor Y:

Speed N (rpm):

Rating life L10h =

3600 h

Precision

Equivalent dynamic load P = XFr + YFa: 5 kN
Rating life L10 = (C/P)ᵏ: 216 million rev
Load ratio C/P: 6

Step-by-step solution

P = 1 × 5 + 0 × 0 = 5 kN
L10 = (C/P)ᵏ = (30 ÷ 5)^3 = 216 million rev
L10h = L10 × 10⁶ ÷ (60N) = 3600 h

Bearing Life Formula

L10 = (C/P)ᵏ × 10⁶ rev, P = XFr + YFa

k = 3 ball, 10/3 roller; L10h = L10 × 10⁶ / 60N

Worked Example

A ball bearing with C = 30 kN under a 5 kN radial load at 1000 rpm:

P = 1 × 5 + 0 × 0 = 5 kN
L10 = (C/P)ᵏ = (30 ÷ 5)^3 = 216 million rev
L10h = L10 × 10⁶ ÷ (60N) = 3600 h

Rating life L10 = (C/P)ᵏ: 216 million rev · Load ratio C/P: 6

Load, speed and reliability

Bearing life falls with the cube of load for ball bearings (power 10/3 for rollers), so a small overload has a large effect: 26 % more load halves a ball bearing’s life. Life in hours also falls in proportion to speed. L10 is the life that 90 % of bearings reach; for higher reliability multiply by a reliability factor (about 0.62 for 95 %, 0.21 for 99 %). Use the equivalent load P = XFr + YFa whenever there is axial load.

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Frequently asked questions

What does L10 life mean?

The life that 90 % of a large group of identical bearings reach or exceed before fatigue failure.

What happens to life if the load doubles?

For a ball bearing life drops to 1/8 (2³); for a roller bearing to about 1/10.

Sources

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.

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APA

Scientific Converters. (2026, October 15). Bearing Life Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/bearing-life-calculator/

IEEE

Scientific Converters, "Bearing Life Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/bearing-life-calculator/