How much grease should a bearing have?

The initial grease fill is typically calculated as G = 0.005 × D × B grams, where D is the bearing OD in mm and B is the width in mm. For regreasing, use 50% of this amount. Actual fill percentage depends on speed — 30-50% of free space is common.

What fill percentage should I use?

For low speed (n×dm 300,000): 25-35%. Sealed bearings from the factory are typically 25-35% filled.

How do I determine the grease volume for relubrication?

For periodic relubrication, use approximately G_regrease = 0.005 × D × B × 0.5 grams. This delivers fresh grease to the contact areas without overfilling the bearing cavity.

Does bearing type affect grease quantity?

Yes. Ball bearings have more internal free space than roller bearings of the same size. The formula G = 0.005 × D × B is a good approximation for all types, but the fill percentage should be adjusted based on bearing type and speed.

Free Engineering Tool #051

Bearing Grease Quantity Calculator

Calculate the recommended grease fill amount for rolling bearings. Formula: G = 0.005 × D × B. Enter bearing OD and width.

G = 0.005 × D × BGramsFill % Guide

Results

Grease Quantity (100% fill)

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Adjusted Quantity (selected fill %)

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Regrease Amount (~50% of full)

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Volume (approx.)

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Grease Quantity Formula

D — bearing outside diameter (mm)
B — bearing width (mm)
G — grease quantity (grams)

Fill Percentage Guide

n × d_m	Speed Category	Recommended Fill
< 100,000	Low speed	50–80%
100,000 – 300,000	Medium speed	30–50%
300,000 – 500,000	High speed	25–35%
> 500,000	Very high speed	20–30%

Practical Example

Example — 6208 Deep Groove Ball Bearing

Given: D = 80 mm, B = 18 mm

G = 0.005 × 80 × 18 = 7.2 grams (100% fill)

At 40% fill: 7.2 × 0.40 = 2.9 grams

Regrease: 7.2 × 0.50 = 3.6 grams

⚠️ Note: Over-greasing is the #1 cause of grease-related bearing failures. When in doubt, use less grease and rely on proper relubrication intervals.

Initial grease fill is calculated as G = 0.005 × D × B grams. For regreasing, use about 50% of this. Actual fill percentage depends on speed — 30-50% of free space is common for normal applications.

Over-greasing causes excessive churning, increased temperature, higher power consumption, and can lead to seal failure and grease leakage. At high speeds, over-greasing is more harmful than under-greasing.

Low speed (n×dm < 100,000): 50-80%. Medium speed: 30-50%. High speed (>300,000): 25-35%. Factory-sealed bearings are typically 25-35% filled.

For periodic relubrication, use approximately 50% of the full fill quantity. This delivers fresh grease to the contact areas without overfilling.

Yes. Ball bearings have more internal free space than roller bearings. The formula G = 0.005 × D × B is a good approximation for all types, but adjust fill percentage for specific bearing type and speed.

The procedures described on this page were developed and field-tested by the Vibromera team using the Balanset-1A, a portable dual-channel balancer and vibration analyzer for on-site rotor balancing.