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Bearing Grease Quantity and Annual Cost Calculator

Over-greasing and under-greasing are both common causes of early bearing failure. This calculator gives a starting grease quantity from bearing size, then scales it to a yearly consumption and cost so you can build a lubrication plan.

Your numbers

Bearing outer diameter D

Bearing width B

Relubrication interval

Run hours per year

Number of similar bearings

Grease price

per kg

Grease gun output per shot

Check the gun with a scale. Many deliver 1 to 2 g per stroke.

Your results

Grease per relubrication

12.5

Grams, from the common G = 0.005 x D x B rule.

Annual grease cost

$12

Gun strokes per bearing

Relubrications per bearing per year

Grease used per year

1.5

The rule is a generic starting point. Follow the bearing and grease supplier's guidance, and note that over-greasing raises temperature and can damage seals.

Save results:

Annual grease cost vs relubrication interval

Sweeps Relubrication interval from 250 to 8000, holding your other inputs fixed.

Lubrication route from ERP data

Optional: turn your equipment list into lubrication work orders.

Optional. The tool and every export work without this. No spam.

How to use it

Read the outer diameter and width from the bearing designation or datasheet. Enter your relubrication interval, annual run hours and the number of similar bearings. Check your grease gun output by weighing ten strokes, and enter the grams per stroke. The result shows grams per shot, strokes per bearing, yearly kilograms and cost. The chart shows how cost reacts if you extend or shorten the interval.

The rule and its limits

A widely used relubrication quantity is G = 0.005 x D x B, with G in grams and D and B in millimetres. The interval depends on speed, temperature, bearing type, grease and contamination, and is best taken from the supplier's chart or from condition monitoring. If ultrasonic or vibration readings stay healthy, the interval can sometimes be extended. If they rise after greasing, the interval or the quantity is probably wrong.

Shorter intervals raise cost but lower the risk of dry running
High temperature roughly halves grease life for every 15 degrees C rise
Do not mix incompatible thickeners

Common mistakes

Using the same shot for every bearing regardless of size is the most common error. Others include skipping a gun calibration, greasing a stationary bearing, and ignoring the drain or relief path so excess grease is forced into the winding of an electric motor. Record every greasing event against the equipment record so intervals can be reviewed against failures.

Not calibrating the grease gun
Greasing with the relief plug still in place
Using one interval for dirty, hot and clean locations alike

Frequently Asked Questions

How much grease should I add to a bearing?

A common starting estimate is 0.005 x outer diameter x width in grams, using millimetres. Always confirm against the bearing or motor manufacturer's nameplate or manual, which takes precedence.

How do I find the relubrication interval?

Use the grease or bearing supplier's interval chart, which accounts for speed factor, bearing type and temperature, then adjust using condition monitoring and inspection history.

What happens if I over-grease?

Excess grease raises churning temperature, can blow out seals and, on motors, push grease into windings. Add slowly with the machine running where the manufacturer allows it.

Does one stroke equal one gram?

Not necessarily. Output varies by gun type and grease stiffness. Weigh ten strokes on a scale and divide to get the real value for your gun.

Netray can generate lubrication routes and work orders from your ERP equipment list so each point gets the correct quantity and interval.

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