Bearing life calculator (L10)
Estimate the basic rating life (L10) of a ball bearing from its dynamic load rating, the applied load and the speed.
Track bearings and maintenance
Tracking bearing life and failures over time? The MTBF, MTTR and availability template is a ready-made starting point for logging maintenance data.
How it is calculated
L10 = (C ÷ P)³ million revolutions for ball bearings. L10h = 10⁶ × L10 ÷ (60 × n) hours.
Worked example
C = 25 kN, P = 5 kN, n = 1500 rpm: L10 = 5³ = 125 million revs, L10h = 125 × 10⁶ ÷ (60 × 1500) = 1388.89 h.
Steps
- Enter the dynamic load rating from the bearing catalog.
- Enter the equivalent load P from your load case.
- Enter the speed, then read L10 and L10h.
Frequently asked questions
Is L10 the expected life?
No. L10 is the life that 90 % of identical bearings reach or exceed. Average life is several times longer.
Does this cover roller bearings?
No. Roller bearings use the exponent 10/3 instead of 3. Use the catalog formula for those.
What about lubrication and contamination?
The basic L10 ignores them. Use the modified life (L10m, ISO 281) when those conditions matter.
Related calculators
References
ISO 281:2007 (basic rating life for rolling bearings); bearing manufacturer catalog for C and P values.
Estimates for information only. Verify critical values with a qualified engineer or your supplier standards.