Bearing Life Calculator
Calculate bearing life step by step: L10 = (C ÷ P)^p million revolutions (ISO 281); L10h = L10 × 10⁶ ÷ (60 × n).
In short
Formula: L10 = (C ÷ P)^p million revolutions (ISO 281); L10h = L10 × 10⁶ ÷ (60 × n).
L10 life
2,400 hours
- Millions of revolutions
- 216
- Load ratio C/P
- 6
What this calculator does
Calculate bearing life step by step: L10 = (C ÷ P)^p million revolutions (ISO 281); L10h = L10 × 10⁶ ÷ (60 × n). Worked example, questions and limitations included.
Use it to turn Bearing type, Basic dynamic load rating C, Equivalent dynamic load P, Speed into a checked result you can compare, copy, or rerun with different assumptions.
The page shows the formula, a numeric worked example, and the assumptions that affect this mechanical calculation.
Inputs and what they mean
- Bearing type
- — choice value.
- Basic dynamic load rating C
- — From the bearing catalogue.
- Equivalent dynamic load P
- — number value.
- Speed
- — number value.
How to use it
- Enter each value in the unit shown next to the box (use the unit converter first if your numbers are in other units).
- Check the breakdown to see every intermediate step.
- Read the limitations before relying on the result.
Formula
p = 3 for ball bearings, 10/3 for roller bearings.
L10 is the life 90% of identical bearings reach or exceed.
C comes from the catalogue; no default rating is assumed.
L10 = (C ÷ P)^p million revolutions (ISO 281); L10h = L10 × 10⁶ ÷ (60 × n).
Inputs used: Bearing type, Basic dynamic load rating C, Equivalent dynamic load P, Speed.
Worked example
Ball bearing, C = 30 kN, P = 5 kN, 1,500 rpm
- L10 = (30 ÷ 5)³ = 216 million revs.
- L10h = 216 × 10⁶ ÷ (60 × 1,500) = 2,400 h.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Basic rating life only (no a1/aISO modification factors).
- Constant load and speed.
- Assumes correct mounting and lubrication.
- Results are estimates for planning and learning. Real designs, installations and bids must be checked by a qualified, licensed professional against the codes that apply where you work.
- The result depends on the values you enter for this bearing life calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Common questions
What does L10 mean?
90% of a large group of identical bearings under the same conditions will reach this life. 10% may fail sooner.
What is equivalent load P?
A single radial load that causes the same life as the actual combined radial and axial loads, calculated with catalogue X and Y factors. Check the formula, example, and limitations on this page before using the result for a real mechanical decision.
Does lubrication change life?
Yes. ISO 281 has a modified life with factors for reliability, lubrication and contamination, not included here.
How do I use the Bearing Life Calculator?
Enter the required values for Bearing type, Basic dynamic load rating C, Equivalent dynamic load P, Speed. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the Bearing Life Calculator use?
L10 = (C ÷ P)^p million revolutions (ISO 281); L10h = L10 × 10⁶ ÷ (60 × n). The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.
Can the Bearing Life Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
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