Bearing Life (L10) Calculator

Basic L10 assumes constant equivalent load and speed.

This selection changes review context only. Formulas and example inputs stay unchanged. Check the model assumptions and applicability for the actual process.

Identify the actual asset, process, work boundary, source documents, units and assumptions. Confirm that the selected model or template applies before using its results.

1 Inputs

Minimum: 0.1

Minimum: 0.1

Minimum: 1

2 Results

L10 rating life
1,389 h
L10 (million rev)
125
L10 (hours)
1,389
L10 (days @24/7)
57.9
Load ratio C/P
5
L10 = (C/P)ᵖ × 10⁶; L10h = L10/(60 × rpm)
Basic L10 assumes constant equivalent load and speed. It is the 90% survival rating, not guaranteed service life. Lubrication, contamination, installation and manufacturer adjustment factors require separate review.

Worked example

Example values are illustrative. Replace them with your measured data.

InputValue
Dynamic load rating C50 kN
Equivalent dynamic load P10 kN
Speed1500 rpm
Bearing typeBall bearing (p = 3)

L10 rating life: 1,389 h

Related tools

About this calculator

How it works

You enter the dynamic load rating C, equivalent dynamic load P, speed in rpm and bearing type. The ISO 281 basic rating life is L10 = (C/P)^p million revolutions, with p = 3 for ball and 10/3 for roller bearings. Hours: L10h = 10⁶ ÷ (60 × rpm) × L10.

Worked example (illustrative inputs)

Ball bearing, C = 50 kN, P = 10 kN, 1,500 rpm: C/P = 5, L10 = 5³ = 125 million revolutions, L10h = 10⁶ ÷ 90,000 × 125 ≈ 1,389 hours, about 58 days of continuous running.

How to read the result

L10 is the life that 90% of identical bearings reach or exceed; 10% fail earlier. The tool marks C/P of 6 or more as good, 4 to 6 as marginal and below 4 as poor. Because of the exponent, halving the load on a ball bearing multiplies life by 8.

When to use it

Use it when selecting a bearing, checking a load change, or setting inspection intervals. Take C from the manufacturer's datasheet and work out P from your radial and axial loads.

À propos de ce calculateur

Traduction (brouillon) — à relire.

Fonctionnement

Vous saisissez la charge dynamique de base C, la charge dynamique équivalente P, la vitesse en tr/min et le type de roulement. La durée nominale ISO 281 est L10 = (C/P)^p millions de tours, avec p = 3 pour les roulements à billes et 10/3 pour les roulements à rouleaux. En heures : L10h = 10⁶ ÷ (60 × tr/min) × L10.

Exemple chiffré (valeurs d'illustration)

Roulement à billes, C = 50 kN, P = 10 kN, 1 500 tr/min : C/P = 5, L10 = 5³ = 125 millions de tours, L10h = 10⁶ ÷ 90 000 × 125 ≈ 1 389 heures, environ 58 jours de marche continue.

Lire le résultat

L10 est la durée atteinte ou dépassée par 90 % de roulements identiques ; 10 % lâchent avant. L'outil juge un C/P de 6 ou plus bon, de 4 à 6 limite et sous 4 faible. À cause de l'exposant, diviser par deux la charge d'un roulement à billes multiplie sa durée par 8.

Quand l'utiliser

Utilisez-le pour choisir un roulement, vérifier un changement de charge ou fixer des intervalles d'inspection. Prenez C dans la fiche du fabricant et calculez P à partir des charges radiale et axiale.

حول هذه الحاسبة

ترجمة (مسودة) — للمراجعة.

طريقة الحساب

تُدخل الحمل الديناميكي المقنّن C والحمل الديناميكي المكافئ P والسرعة بالدورة/دقيقة ونوع المحمل. العمر الاسمي وفق ISO 281 هو L10 = (C/P)^p مليون دورة، حيث p = 3 للمحامل الكروية و10/3 للأسطوانية. وبالساعات: L10h = 10⁶ ÷ (60 × السرعة) × L10.

مثال محسوب (قيم توضيحية)

محمل كروي، C = 50 kN وP = 10 kN و1500 دورة/دقيقة: C/P = 5، وL10 = 5³ = 125 مليون دورة، وL10h = 10⁶ ÷ 90000 × 125 ≈ 1389 ساعة، أي نحو 58 يومًا من التشغيل المتواصل.

قراءة النتيجة

L10 هو العمر الذي يبلغه أو يتجاوزه 90% من المحامل المتماثلة؛ و10% تتعطل قبله. تعدّ الأداة C/P بقيمة 6 فأكثر جيدة، ومن 4 إلى 6 حدّية، ودون 4 ضعيفة. وبسبب الأس، فإن خفض الحمل على محمل كروي إلى النصف يضاعف عمره 8 مرات.

متى تستخدمه

استخدمها عند اختيار محمل أو فحص تغيّر في الحمل أو تحديد فترات الفحص. خذ C من نشرة الصانع واحسب P من الحملين الشعاعي والمحوري.

In one line

Basic L10 assumes constant equivalent load and speed. It is the 90% survival rating, not guaranteed service life. Lubrication, contamination, installation and manufacturer adjustment factors require separate review.

Worked example

EXAMPLE

Illustrative values (the calculator defaults), not data from a real site.

Inputs
Dynamic load rating C50 kN
Equivalent dynamic load P10 kN
Speed1500 rpm
Bearing typeBall bearing (p = 3)
Results
L10 rating life1,389 h
L10 (million rev)125
L10 (hours)1,389
L10 (days @24/7)57.9
Load ratio C/P5

Frequently asked questions

What's a good C/P load ratio to aim for?

The tool flags C/P of 6 or higher as good and lower ratios as marginal or poor, since a low ratio means the bearing is working close to its rated capacity and life falls off quickly. The exact ratio you need depends on your reliability target and duty cycle, so check the bearing manufacturer's selection guide for your specific application.

Where do I find the dynamic load rating C and equivalent load P?

C is published in the bearing manufacturer's catalogue for the specific bearing part number. P is calculated from your actual radial and axial loads using the manufacturer's equivalent-load formula (which combines them with load factors X and Y) — if you only have the raw radial and axial loads, you'll need that formula or the manufacturer's selection software first.

Why does bearing type (ball vs roller) change the answer?

The exponent in the life formula differs because ball and roller bearings have different contact geometry (point contact vs line contact) and therefore different fatigue behaviour under load — roller bearings use an exponent of 10/3 instead of 3, which changes how sensitively predicted life responds to load.

Does L10 mean my bearing will definitely last that long?

No — L10 is a statistical life where 90% of an identical bearing population reaches or exceeds that life, and 10% fail earlier. Actual field life also depends heavily on lubrication, contamination, alignment and installation quality, which the basic L10 formula doesn't capture on its own.

Why is the result so sensitive to the load I enter?

Bearing life follows a power law of load, so even modest increases in equivalent load produce large drops in expected life — for a ball bearing, doubling the load cuts life to roughly one-eighth. This is exactly why misalignment, imbalance and overloading are such common root causes of premature bearing failure.

Donate · Faire un don · تبرّع