Fareed Mohmed · Engineering

Bearing Load, Life & Static Capacity Calculator

React · Rate · Verify

Work a bearing from the actual shaft loads through to a pass/fail: reactions at the bearings, the equivalent dynamic load, the basic rating life (ISO 281), and the static safety factor (ISO 76) — each section usable on its own.

The X, Y, C and C0 factors below are bearing-specific and come from your bearing's own catalog page — this tool intentionally doesn't assume one generic factor set for every bearing, since using the wrong one silently gives a wrong answer. Treat this as a verification and life-estimation tool for a bearing you've already selected, not a substitute for the manufacturer's data.

Shaft Reaction Calculator

A simply-supported shaft on two bearings with a single radial point load. Enter the span and load position to get each bearing's radial reaction.

Bearing Span, L mm, A to B

Load Position, a mm from bearing A

Radial Load, Fr N

Axial Load, Fa N, on the locating bearing

Locating (Axial-Taking) Bearing

Radial Reaction at Bearing A—

Radial Reaction at Bearing B—

Axial Load on Locating Bearing—

Axial Load on Non-Locating Bearing0 N (floats axially)

Simple statics for one point load: R_A = F_r·(L−a)/L, R_B = F_r·a/L. For multiple loads in different planes, or belt/gear force components, resolve each plane separately and combine by superposition before using the result below.

Equivalent Dynamic Load

P = X·F_r + Y·F_a. Use X = 1, Y = 0 whenever F_a/F_r is at or below your bearing's e value — above e, use the X and Y published on your bearing's catalog page.

Radial Load, F_r N

Axial Load, F_a N

Radial Factor, X from catalog (1 if radial only)

Axial Factor, Y from catalog (0 if radial only)

Equivalent Dynamic Load, P—

Copy this P value into the Basic Rating Life section below.

Basic Rating Life — L₁₀ / L_10h

L₁₀ = (C/P)^p million revolutions, per ISO 281. L₁₀ is the life 90% of an identical population of bearings is expected to reach or exceed — a statistical rating, not a guarantee for any one bearing.

Dynamic Load Rating, C N, from catalog

Equivalent Dynamic Load, P N, from section 02

Bearing Type

Operating Speed, n RPM

Basic Rating Life, L₁₀—

Basic Rating Life, L_10h—

Basic Rating Life—

Reverse: Required Dynamic Load Rating for a Target Life

Required Life hours

Operating Speed RPM

Equivalent Dynamic Load, P N

Minimum Dynamic Load Rating, C required—

Pick a bearing whose catalog C meets or exceeds this value at the load and speed you've entered.

Static Safety Factor

s₀ = C₀/P₀, per ISO 76. Static capacity matters even for a continuously rotating bearing whenever it also sees peak shock loads, intermittent starts, or is stationary under load at some point in its duty cycle.

Static Load Rating, C₀ N, from catalog

Radial Load, F_r N

Axial Load, F_a N

Required Safety Factor see guidance below

Static Radial Factor, X₀ 0.6 is standard for deep groove ball — confirm for your bearing

Static Axial Factor, Y₀ 0.5 is standard for deep groove ball — confirm for your bearing

Equivalent Static Load, P₀—

Calculated Static Safety Factor, s₀—

Result—

Reference Tables

Bearing Family	Life Exponent, p
Ball bearings (all types)	3
Roller bearings (all types)	10/3 ≈ 3.33

Per ISO 281. Roller bearings have a shallower life-vs-load curve than ball bearings.

Bearing Type	Static X₀	Static Y₀
Deep Groove Ball	0.6	0.5
Angular Contact Ball (single row, 40° contact angle)	0.5	0.26
Other types (roller, tapered, spherical, needle)	Varies significantly by design — use your bearing's catalog value

Per ISO 76. These two rows are widely standardized; everything else genuinely depends on the specific bearing's internal geometry.

Application Character	Typical Required s₀
Smooth running, low noise requirement (precision spindles)	1.5 – 2.5
Normal operation, light to moderate shock	1.0 – 1.5
Normal operation with some shock expected	1.5
Significant shock or vibration loading	2.0 – 3.0

Typical starting-point guidance, not a hard limit — pick the value that matches your application's loading uncertainty and consequence of overload.

Explanatory Notes

L10 life is a statistical rating, not a promise

L10 is the life that 90% of a large population of identical bearings, under identical conditions, is expected to reach or exceed before the first sign of fatigue. Any individual bearing might fail well before it, or run for many times longer — and this basic calculation doesn't account for lubrication quality, contamination, misalignment or improper mounting, all of which shorten real-world life independently of the load rating.

Why check static capacity on a bearing that's always rotating

The dynamic rating (C, L10) describes fatigue life under continuous rotation. It says nothing about a momentary overload, a shock load at start-up, or the bearing sitting stationary under load between cycles — those situations can locally deform the raceway (brinelling) well within the dynamic life rating. The static safety factor check exists specifically to catch that case.

Where X, Y, C and C0 actually come from

These four numbers are published per bearing designation in the manufacturer's catalog (SKF, Schaeffler/FAG/INA, NSK, NTN, Timken, JTEKT/Koyo, and others) — they depend on the bearing's internal geometry, not just its type, and different manufacturers' internal designs can carry different ratings for a nominally similar bearing. Pulling a number from the wrong bearing's catalog page, or reusing one bearing's X/Y for another, is the single most common way this kind of calculation goes wrong.

Related tools

To first identify which bearing type suits the application, see the Bearing Type Selector. To shortlist a standard-series bearing by bore and envelope, see the Bearing Size Finder. For the shaft and housing fit once a bearing is selected, see the Shaft & Housing Fit Calculator.