What Is L10 Bearing Life?
L10 life (also called basic rating life) is the number of revolutions (or hours at a given speed) that 90% of a sufficiently large group of identical bearings can be expected to endure before the first evidence of fatigue appears. It is calculated per ISO 281 and is the primary metric for bearing selection and comparison.
The L10 Formula
L10 = (C / P)^p million revolutions. C = dynamic load rating, P = equivalent bearing load, p = 3 (ball) or 10/3 (roller). For hours: L10h = (10^6 / 60n) x L10. The Bearing Selection Guide includes an interactive L10 calculator.
Frequently Asked Questions
How do you calculate L10 bearing life?
L10 = (C/P)^p, where C = basic dynamic load rating (from catalogue), P = equivalent dynamic bearing load, and p = 3 for ball bearings or 10/3 for roller bearings. The result is in millions of revolutions. Convert to hours: L10h = (10^6 / 60n) x L10, where n is RPM.