AtlasCalcsUtility Calculation Suite
August 2026 12 min read

Bearing Load Calculator

Free bearing load calculator. Compute resultant radial load, equivalent dynamic load P, static equivalent load P₀, and X/Y/e factors for deep groove, angular contact and cylindrical roller bearings.

Bearing Load Calculator

Bearing Load Inputs

Unit System
SI — N Imperial — lbf
Horizontal Radial F_h (N)
N

Force in the horizontal plane

Vertical Radial F_v (N)
N

Force in the vertical plane

Axial Load F_a (N)
N

Thrust along the shaft axis

Static Load Rating C₀ (N)
N

From the bearing catalogue

Bearing Type

Sets the X/Y/e factor table

Load Factor f_s

Shock / application severity

Auto-calculate instantly

Equivalent Dynamic Load P

5,125N

Axial-adjusted constant load the bearing must carry (incl. load factor 1).

Moderately loaded — normal life
Resultant Radial F_r

5,000N

Equivalent Static P₀

5,000N

F_a / F_r

0.3

e (limiting)

0.28

X / Y factors

0.56 / 1.55

P / C₀ ratio

0.2562

F_a / C₀

0.075

Load factor

1

Resultant Radial F_r

5,000N

√(F_h² + F_v²)

Equivalent Static P₀

5,000N

0.6·F_r + 0.5·F_a (min F_r)

F_a / F_r

0.3

Threshold e = 0.28

e (limiting)

0.28

Use full X·F_r + Y·F_a if exceeded

X / Y factors

0.56 / 1.55

From F_a/C₀ table

P / C₀ ratio

0.2562

Severity indicator

F_a / C₀

0.075

Sets the X/Y table

Load factor

1

Shock / application severity

Result Summary

Bearing TypeDeep Groove Ball (contact ≈ 0°)
Horizontal radial F_h3,000 N
Vertical radial F_v4,000 N
Axial load F_a1,500 N
Resultant radial F_r5,000 N
Equivalent dynamic P5,125 N
Equivalent static P₀5,000 N
Static rating C₀20,000 N
Selection verdictModerately loaded — normal life
Estimated Result — Uses ISO 281 equivalent-load convention with standard catalogue X/Y/e tables for the three supported bearing families. For tapered or spherical roller bearings use the manufacturer's exact factors. Shock, misalignment, lubrication and mounting are covered by the load factor but not by the static correction — verify against the governing design code.

Interactive Diagram

Diagram scales live with your inputs: red arrows are radial components, the blue arrow is axial thrust, and the dashed line is the resultant on the supports.

Visualizations

Load Overview

3,000NF_h
4,000NF_v
1,500NF_a (axial)
5,000NF_r (resultant)
5,125NP (equiv.)

Load Severity (P / C₀)

P used / C₀26%

Formula

The resultant radial load is the vector sum of the horizontal and vertical components. The equivalent dynamic load collapses the real combined load into a single constant radial load giving the same fatigue life. The axial load only matters once F_a/F_r exceeds the limit e, which itself grows with F_a/C₀.

P = X·F_r + Y·F_a (if F_a/F_r > e) | P = F_r (if F_a/F_r ≤ e)

Alternative Form

P₀ = 0.6·F_r + 0.5·F_a (≥ F_r) | F_r = √(F_h² + F_v²)

Variables

SymbolNameUnitDescription
F_rResultant radial loadN√(F_h² + F_v²) — total perpendicular-to-shaft force
F_h, F_vRadial componentsNHorizontal and vertical plane forces on the shaft
F_aAxial (thrust) loadNForce parallel to the shaft axis
C₀Static load ratingNCatalogue permanent-deformation limit
XRadial factor—1 when axial negligible, else 0.44–0.56
YAxial factor—Grows with F_a/C₀
eLimiting ratio—Threshold F_a/F_r for axial significance
PEquivalent dynamic loadNConstant load for life comparison
P₀Equivalent static loadNUsed for stationary / slow checks
f_sLoad factor—Shock / severity multiplier on P

Explanation

Rolling-element bearings fail by subsurface fatigue, so life depends on the peak contact stress set by the load. Because axial and radial loads create different contact-stress patterns, standards define an equivalent radial load P that reproduces the same stress field as the real combined load. The X/Y/e machinery encodes the bearing geometry: a deep groove ball develops a small contact angle under axial load and therefore needs a large Y, whereas an angular-contact bearing already has a large contact angle and needs little correction.

Derivation

Starting from the Lundberg–Palmgren life model, the dynamic capacity C relates to life by L10 = (C/P)^p (p = 3 for balls, 10/3 for rollers), millions of revolutions. The equivalent load is the load that, when substituted for the real load, yields the same orthodox stress. Catalogue committees fit X, Y and e from the contact mechanics of each bearing type as functions of F_a/C₀, which is why the table lookup is used rather than a single closed form.

Step-by-Step Calculation

Follow each step to understand how the result is calculated from your inputs.

Step 1

Combine the radial force components into a single resultant.

F_r = √(F_h² + F_v²)
F_h:3,000 N
F_v:4,000 N
Intermediate: F_r = 5,000 N
Result: Resultant radial load established
Step 2

Form the axial-to-static-rating ratio that selects the X and Y factors.

F_a / C₀ → table
F_a:1,500 N
C₀:20,000 N
Intermediate: F_a/C₀ = 0.075
Result: Chosen e = 0.28, X = 0.56, Y = 1.55
Step 3

Test whether the axial load is significant.

if F_a/F_r ≤ e → P = F_r
F_a/F_r:0.3
e:0.28
Intermediate: Axial load significant — full form used
Result: P = 5,125 N
Step 4

Apply the application (shock) load factor for real service.

P_used = f_s · P
f_s:1
P:5,125 N
Intermediate: P_used = 1 × 5,125
Result: P_used = 5,125 N
Step 5

Compute the static equivalent load for stationary / slow checks.

P₀ = max(0.6·F_r + 0.5·F_a, F_r)
F_r:5,000 N
F_a:1,500 N
Intermediate: P₀ = 5,000 N
Result: Static check value ready
Step 6

Assess load severity against the dynamic rating.

P/C₀
P_used:5,125 N
C₀:20,000 N
Intermediate: P/C₀ = 0.2562
Result: Moderately loaded
Final Answer
5,125 N

Worked Examples

See how the calculator works with different scenarios.

Scenario

A fan shaft on deep groove bearings with modest combined load.

Inputs

F_h:2000 N
F_v:1500 N
F_a:300 N
C₀:18000 N
Bearing:Deep groove ball

Calculation

F_r = √(2000²+1500²) = 2500 N; F_a/C₀ = 300/18000 = 0.0167 → e = 0.22, Y = 1.99; F_a/F_r = 0.12 ≤ e → P = F_r = 2500 N

Result

P = 2500 N, P/C₀ = 0.139 (light load, long life)

Interpretation

A lightly loaded electric-motor style bearing — life will be very long; a smaller standard size may suffice.

Understanding Your Result

Your Result: 5,125 N

Typical range: Healthy designs target P/C₀ below 0.15 (very long life) to about 0.3 (normal life). Yours is 0.2562 — typical.

What This Means

Your load combination produces a resultant radial force of 5,000 N and an equivalent dynamic load of 5,125 N (including the 1× application factor). The static equivalent is 5,000 N. The P/C₀ ratio is 0.2562.

Why It Matters

The equivalent load is the single number that unlocks the life equation L10 = (C/P)^p. Get P wrong — by ignoring thrust, shock, or the correct X/Y factors — and the predicted bearing life can be off by an order of magnitude, causing unexpected premature failures.

Professional Interpretation

Load is normal for industrial service — proceed to a life check.

Factor selection

With F_a/C₀ = 0.075 the table gives e = 0.28, X = 0.56, Y = 1.55 for the chosen deep-groove family.

Static vs dynamic

P₀ = 5,000 N guards stationary or very slow shafts; dynamic P = 5,125 N drives fatigue life.

Severity

P/C₀ = 0.2562 — the industry rule of thumb is: < 0.1 very light, 0.1–0.3 normal, > 0.3 heavy.

Recommendations

  • •Always include the application (shock) factor — start/stop and impact duty can double the effective load.
  • •Because F_a/F_r exceeds e, the axial load drives P upward; verify the thrust capacity independently.
  • •For combined heavy radial + axial service, prefer angular contact or tapered roller bearings over deep groove types.
  • •Carry P into a bearing life calculation (L10) before final selection — load alone does not prove adequacy.

Educational Content

Introduction

Every rotating shaft is carried by bearings, and every bearing lives or dies by the load it sees. The bearing load calculator turns the messy reality of horizontal, vertical and axial forces into the single equivalent load that the international life standards are built around. Mastering it is the first step in any reliable rotating-machine design.

Concept Explanation

A bearing experiences a radial force (perpendicular to the shaft) and often an axial or thrust force (parallel to the shaft). The radial components add vectorially to a resultant F_r. Standards then ask: what constant radial load P would wear the bearing out at the same rate as the real combined load? For small axial loads the answer is simply P = F_r; once the axial load passes a geometry-dependent threshold e, an X·F_r + Y·F_a correction is added. A separate static equivalent P₀ protects bearings that rarely turn. The ratio P/C₀ — equivalent load to catalogue dynamic rating — is the quick severity gauge that drives selection.

Applications

▸Sizing bearings for electric motors, pumps and fans
▸Rating gearbox bearing arrangements under helical-gear thrust
▸Checking belt- and chain-drive radial reactions
▸Verifying overhung pulleys and wheel axles
▸Preliminary selection before a full L10 life calculation
▸Troubleshooting premature bearing failures

Benefits

  • •Converts 3-D load vectors into one comparable number
  • •Applies the correct ISO 281 X/Y/e correction automatically
  • •Flags axial significance you might otherwise overlook
  • •Gives an instant severity check via P/C₀
  • •Handles SI and imperial units consistently

Limitations

  • •Uses generic catalogue tables — tapered/spherical rollers need maker-specific factors
  • •Does not compute L10 life itself (feed P to a life calculator)
  • •Ignores lubrication film, temperature and mounting preload details
  • •Load factor is a coarse proxy for dynamics, not a vibration analysis
  • •Single bearing only — paired/back-to-back arrangements need special handling

Best Practices

  • •Resolve every external force into horizontal and vertical radial components first
  • •Apply the real application (shock) factor, not 1.0, for machinery that starts/impacts
  • •Keep P/C₀ under about 0.3 for mainstream industrial duty
  • •Confirm the axial load is within the bearing family's thrust limit
  • •Follow the equivalent load with an L10 life and a static safety check

Common Misconceptions

Myth: Axial load never matters for a deep groove bearing.
Truth: Once F_a/F_r exceeds e (which falls as F_a/C₀ rises), the axial load must enter P via the Y factor or the life prediction is optimistic.
Myth: P is just the biggest force present.
Truth: P is a weighted combination (X·F_r + Y·F_a); for a pure radial load it equals F_r, but thrust can dominate the result.
Myth: A high C₀ alone guarantees a long life.
Truth: Dynamic life depends on C (dynamic rating) versus P; C₀ only bounds permanent static deformation.
Myth: The load factor is optional polish.
Truth: Ignoring shock can halve or quarter the real life — crushers and vibrators routinely need factors of 2–3.

Practical Tips

  • •Current P/C₀ = 0.2562. Aim below 0.3 so normal wear, not overload, sets the life.
  • •Resolve external forces into F_h and F_v with a free-body diagram before typing numbers — sign errors are the usual mistake.
  • •If F_a/F_r is just under e, a small extra thrust flips the formula; re-check whenever thrust changes.
  • •For belts and chains, remember the radial load is roughly 2–2.5× the effective (tight−slack) tension.
  • •Keep the catalogue C₀ handy — it is what sets the X/Y/e table through F_a/C₀.

Common Mistakes

Mixing unit systems
Entering pounds where the field expects newtons silently inflates P and P/C₀ by 4.45. Set the unit system first, then enter matching values.
Forgetting the application factor
Using f_s = 1.0 for shock-loaded plant makes P far too small; pick 1.5–3.0 for gears, crushers and vibrators.
Ignoring the axial load below e
Below e the axial load correctly drops out of P — but it still must be checked against the bearing's separate thrust capacity.
Using P/C₀ as the life
P/C₀ is only a severity hint. Real life is L10 = (C/P)^p; a low P/C₀ still needs the full life check.
Wrong bearing family table
Angular contact and roller bearings use different X/Y/e tables than deep groove balls; select the family that matches your component.

Assumptions

This calculator makes the following assumptions to provide estimates:

ISO 281 equivalent-load form: The P = X·F_r + Y·F_a convention with catalogue X/Y/e tables is assumed.
Steady load direction: Loads are treated as constant in magnitude and direction; rotating loads are not separated.
Rigid shaft and housing: Deflection and housing flexibility that shift load distribution are ignored.
Application factor covers dynamics: Shock, vibration and misalignment are represented only by the scalar f_s.

Limitations

Be aware of these limitations when using this calculator:

Single bearing: Paired, back-to-back or tandem arrangements need combined-load methods.
Generic factors: Tapered and spherical roller bearings require manufacturer-specific X/Y/e values.
No life output: This tool gives P; an L10 life calculator completes the selection.
Excludes lubrication: Film thickness, contamination and lubrication regime are not modelled.

Frequently Asked Questions

Answers to common questions about this calculator.

What is a bearing load?
A bearing load is the force applied to a bearing during operation. It consists of radial loads (perpendicular to the shaft axis), axial loads (parallel to the shaft axis), and moment loads. The magnitude and direction of the loads determine bearing selection, life, and performance.
How is resultant radial load calculated?
The resultant radial load combines the horizontal and vertical components using vector addition: F_r = √(F_h² + F_v²), where F_h is the horizontal radial force and F_v is the vertical radial force. This gives the total radial load acting on the bearing.
What is equivalent dynamic load P?
The equivalent dynamic load P is a hypothetical constant radial load that produces the same bearing life as the actual combination of radial and axial loads. For radial bearings: P = X·F_r + Y·F_a when F_a/F_r > e, or P = F_r when F_a/F_r ≤ e.
What are X and Y factors?
X is the radial load factor and Y is the axial load factor used in the equivalent load equation P = X·F_r + Y·F_a. These factors depend on bearing type, contact angle, and the ratio F_a/C₀ (axial load to static load rating).
What is the e value in bearing load calculation?
The e value (limiting factor) determines whether the axial load significantly affects the equivalent load. If F_a/F_r ≤ e, then P = F_r (axial load negligible). If F_a/F_r > e, then P = X·F_r + Y·F_a must be used.
How do I calculate equivalent static load P₀?
The equivalent static load P₀ is used for static capacity checks. For radial bearings: P₀ = 0.6·F_r + 0.5·F_a (simplified). If P₀ < F_r, use P₀ = F_r. This accounts for combined radial and axial loads under static conditions.
What is deep groove ball bearing load capacity?
Deep groove ball bearings handle primarily radial loads but can accommodate moderate axial loads. The axial load capacity depends on the load ratio, internal clearance, and contact angle development under load. Maximum axial load is typically 0.5–1.5 times the static load rating.
What is the F_a/C₀ ratio?
The F_a/C₀ ratio is the axial load divided by the static load rating. It determines which X and Y factors apply. Higher values indicate larger axial loads relative to bearing static capacity, requiring larger Y factors in the equivalent load calculation.
What is the P/C ratio?
The P/C ratio is the equivalent dynamic load divided by the dynamic load rating. It indicates how heavily loaded the bearing is. Lower P/C ratios (e.g., 0.05–0.15) provide long bearing life. Higher ratios (>0.3) result in shorter life.
How does load direction affect bearing selection?
Load direction determines bearing type selection: pure radial loads use cylindrical roller or deep groove ball bearings, pure axial loads use thrust bearings, combined loads use angular contact or tapered roller bearings with appropriate contact angles.
What are radial loads in bearings?
Radial loads act perpendicular to the shaft axis, typically from gear tooth forces, belt tension, or the weight of rotating components. They are the primary load component for most rotating machinery and are supported by the bearing radial capacity.
What are axial (thrust) loads in bearings?
Axial loads act parallel to the shaft axis, from helical gear forces, thrust from pumps or compressors, or axial positioning forces. They require bearings with axial capacity like angular contact ball bearings, tapered roller bearings, or thrust bearings.
How do I calculate bearing loads on a shaft?
Bearing loads on a two-support shaft are calculated using static equilibrium: sum of vertical forces = 0, sum of horizontal forces = 0, sum of moments = 0. The reactions at each bearing support are the resultant radial loads from the force components.
What is a moment load on a bearing?
A moment (overturning) load occurs when the line of action of the applied load does not pass through the bearing centre. This creates an additional moment that must be resisted by the bearing. Moment loads are common in overhung pulley or gear arrangements.
How does speed affect bearing load capacity?
At high speeds, centrifugal forces on rolling elements and gyroscopic effects reduce load capacity. The dynamic load rating must be derated using speed factors. For dn > 100,000 mm·r/min, special high-speed bearing designs with different materials and cage designs are needed.
What are static loads and dynamic loads?
Static loads occur when the bearing is stationary or rotating very slowly. They limit the bearing by permanent deformation of rolling elements and raceways. Dynamic loads occur during rotation and limit the bearing by fatigue life. Both must be checked in bearing selection.
How do I calculate bearing loads for gear drives?
Gear drives produce radial loads from gear tooth contact forces, and axial loads from helical or bevel gear thrust. The radial load on each bearing depends on the gear mesh location and power transmitted. Use gear force components with moment equilibrium equations.
What is the load factor in bearing calculations?
The load factor accounts for dynamic effects, shock loads, and application severity. Typical factors: 1.0–1.2 for smooth operation (electric motors), 1.2–1.5 for moderate shock (pumps, fans), 1.5–3.0 for heavy shock (crushers, vibrating screens).
How does bearing clearance affect load distribution?
Internal clearance affects how many rolling elements share the load. With normal clearance (CN), approximately 40–50% of balls share the radial load. With increased clearance (C3), fewer balls share the load, increasing maximum ball load and reducing life.
What is the effect of misalignment on bearing loads?
Misalignment creates edge loading on the bearing, increasing the effective load and reducing life. For angular contact bearings, misalignment changes the contact angle and load distribution. Maximum allowable misalignment: deep groove 2–4 arcmin, spherical roller 1–2°.
How do preloaded bearings affect loads?
Preloaded bearings have an internal load applied during assembly to eliminate clearance. This increases stiffness but adds a preload load to the bearing load calculation. The effective bearing load is the sum of applied loads and preload.
What is the bearing load for belt drives?
Belt drives produce radial loads from belt tension. The effective tension T_eff = T_tight − T_slack, and the resultant force on the shaft depends on wrap angle and belt type. V-belts typically produce 1.5–2.5 times the effective tension as radial load.
How do I calculate overhung load on bearings?
Overhung loads occur when a pulley, gear, or sprocket is mounted beyond the bearing support. The radial load at the bearing is F_bearing = F_load × (L_overhang/L_bearing_spacing + 1). Overhung loads significantly increase bearing reactions.
What is the load eccentricity in bearings?
Load eccentricity is the offset between the load application point and the bearing centre. It creates moment loads that must be handled by the bearing arrangement. Two bearings spaced apart can resist moment loads as a force couple.
How do I account for shock loads?
Shock loads (impact, vibration) are accounted for using application factors that multiply the calculated load. Typical shock factors: 1.0 (uniform), 1.5 (light shock), 2.0 (moderate shock), 3.0 (heavy shock). The equivalent load P is multiplied by the shock factor.
What is the difference between point and line contact?
Ball bearings have point contact (elliptical contact area under load). Roller bearings have line contact (rectangular contact area). Line contact provides higher load capacity but is more sensitive to misalignment. Point contact allows higher speeds with lower friction.
How does temperature affect bearing load rating?
At elevated temperatures (>150°C), bearing steel hardness decreases, reducing the dynamic load rating. The C rating must be derated by 0.95 at 150°C, 0.90 at 200°C, 0.75 at 250°C. High-temperature bearings use special steels with better hot hardness.
What is the load-life relationship?
Bearing life is inversely proportional to load raised to the power p: L ∝ 1/P^p (p = 3 for ball, 10/3 for roller). A 25% increase in load reduces ball bearing life by approximately 50%. Conversely, reducing load by 25% doubles the life.
What is the C/P ratio?
The C/P ratio (dynamic load rating / equivalent dynamic load) is a key indicator of bearing load severity. Values >10 indicate light loading (very long life), 5–10 moderate, 2–5 heavy, <2 extreme (very short life). Target C/P depends on required life and speed.
How do I select bearing type based on load?
Load-based selection: pure radial → cylindrical roller or deep groove ball. Pure axial → thrust bearing (ball or roller). Combined radial + axial, F_a/F_r small → deep groove ball. Combined, F_a/F_r large → angular contact ball or tapered roller.
What is the maximum axial load for deep groove bearings?
Deep groove ball bearings can handle axial loads up to approximately 0.5 × C₀ (static load rating) for intermittent loads, or 0.25 × C₀ for continuous operation. Higher axial loads require angular contact bearings with defined contact angles.
How do double row bearings handle loads?
Double row bearings handle higher radial loads than single row equivalents. They can also handle axial loads in both directions. However, they have lower speed capability and generate more heat than single row bearings of similar size.
What is the bearing load from unbalance?
Rotating unbalance creates a centrifugal force F_unbalance = m·e·ω², where m is the unbalanced mass, e is the eccentricity, and ω is the angular velocity. This force rotates with the shaft and creates a cyclic radial load on the bearings.
Can I use this calculator for all bearing types?
This calculator supports deep groove ball bearings, angular contact bearings, and cylindrical roller bearings with appropriate X, Y, and e factors. For tapered roller or spherical roller bearings, use manufacturer-specific X and Y factors from their catalogues.
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Glossary

Technical terms used in mortgage calculations explained in plain language.

Radial Load (F_r)
The total force perpendicular to the shaft axis, obtained as the vector sum of horizontal and vertical components: F_r = √(F_h² + F_v²).
Axial Load (F_a)
The force parallel to the shaft axis (thrust), from helical gears, belts, or positioning forces.
Equivalent Dynamic Load (P)
A constant radial load that, if applied, would give the same life as the actual combined load. P = X·F_r + Y·F_a when F_a/F_r > e.
Equivalent Static Load (P₀)
The load used for static-capacity checks: P₀ = 0.6·F_r + 0.5·F_a, but never less than F_r.
Dynamic Load Rating (C)
The constant load a bearing can endure for a rated life of 1 million revolutions (L10). Published in manufacturer catalogues.
Static Load Rating (C₀)
The load that produces a total permanent deformation of 0.0001 of the rolling element diameter at the contact — the limit for stationary or very slowly rotating bearings.
X Factor
Radial load factor in the equivalent-load equation; equals 1 when axial load is negligible (F_a/F_r ≤ e).
Y Factor
Axial load factor in the equivalent-load equation; grows as the F_a/C₀ ratio increases.
e (Limiting Ratio)
The threshold F_a/F_r above which the axial load can no longer be ignored and the full X·F_r + Y·F_a form is required.
P/C₀ Ratio
Severity indicator: equivalent dynamic load divided by dynamic rating. Lower means longer life.
L10 Life
The life exceeded by 90% of a group of identical bearings under identical conditions — the rated fatigue life.
Load Factor (a_ISO / f_s)
Multiplier for shock, vibration, and application severity that increases the effective load for conservative design.

Authoritative References

Trusted sources and standards referenced by this calculator.

Applicable Standards

ISO 281ISO 76 (static)ABMA / ANSISKF General CatalogueSchaeffler Rolling Bearing Calculation

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Page Information

Last Updated:

August 2026

Version:

2.1.0

License:

Free to use for educational and professional purposes.