Friability Calculation Formula

Friability Test Procedure

For tablets with a unit weight equal to or less than 650 mg, take a sample of whole tablets corresponding as near as possible to 6.5 g. For tablets with a unit weight of more than 650 mg, take a sample of 10 whole tablets. The tablets should be carefully dedusted prior to testing. Accurately weigh the tablet sample, and place the tablets in the drum. Rotate the drum 100 times, and remove the tablets. Remove any loose dust from the tablets as before, and accurately weigh.

If tablet size or shape causes irregular tumbling, adjust the drum base so that the base forms an angle of about 10° with the horizontal and the tablets no longer bind together when lying next to each other, which prevents them from falling freely.

Effervescent tablets and chewable tablets may have different specifications as far as friability is concerned. In the case of hygroscopic tablets, an appropriate humidity-controlled environment is required for testing.

Percentage Friability Formula 

Friability (%) = (W1 – W2)/ W1 X 100


  • W1 = Initial weight
  • W2 = Finial weight (after rotation)

For determination of the friability of granules and spheroids:


Friability Test Limit as per USP, EP/BP

A maximum mean weight loss from the three samples of not more than 1.0% is considered acceptable for most products.

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