Bearing Life Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
Enter Values
How to use this calculator
- Enter the bearing's dynamic load rating C (kN) and the equivalent dynamic load P (kN).
- Optionally add the speed (rev/min) to get life in hours.
- Read the basic rating life for ball and roller bearings.
How it works
The Bearing Life Calculator finds the basic rating life L₁₀ — the life that 90% of a group of bearings will reach or exceed under a given load.
L₁₀ = (C/P)ᵖ million revolutions, where p is 3 for ball bearings and 10/3 for roller bearings. With a speed, life in hours is L₁₀ₕ = L₁₀ × 10⁶ ÷ (60 × rev/min).
Worked example
C 30 kN, P 3 kN at 1500 rpm. Ratio C/P = 10, so a ball bearing's L₁₀ = 10³ = 1000 million revolutions — about 11,100 hours at 1500 rpm.
Frequently asked questions
Is L₁₀ the bearing's guaranteed life?
No — it's a statistical figure: 90% of identical bearings should reach it. Individual bearings vary, and real life depends heavily on lubrication, cleanliness, alignment and temperature.
Can I use these results for final design?
No. These calculators are for first-pass sizing, checking and learning. They assume ideal supports, static loads and elastic behaviour, and they don't apply load factors, member capacity, buckling or connection checks. Always verify against the relevant design code (e.g. AS 4100, AS 1170, Eurocode) and have a qualified engineer sign off structural work.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.