Angle of Repose Calculator

How to Use the Angle of Repose Calculator

• Enter pile height (H) and diameter (D).

• The calculator applies the formula:
  θ = arctan(2H / D)

• The angle of repose indicates powder flowability.

• Compare your result with the table of flow ratings below.

• Watch the video for how to measure correctly.

Please enter the height and diameter below:

Now that you have the result you can compare it to the following table to determine its relative ability to be able to flow.

Angle Of Repose (degrees)	Expected Flow
25-30	Excellent
31-35	Good
36-40	Fair - aid not needed
41-45	Passable - may hang up
46-55	Poor - must agitate or vibrate
56-65	Very Poor
>66	Very, Very Poor

If your powder has an angle of repose that is higher than 45° then it is likely that it will not be suitable for tablet pressing. If this is the case then we strongly recommend that you add a flowing agent to it.

The angle of repose is important in understanding how well a powder will flow through your machine. LFA has developed this Angle Of Repose Calculator to help you quickly and easily calculate any angle of repose.

Simply enter the height of your pile of powder in cm in the section below labelled "H" and the diameter of the base of your pile of powder in the section labelled "D". The calculator will then calculate the angle of repose in degrees for you.

Here is a video on how best to take the measurements: