Calculate grain bin capacity, partial-fill bushels, and fill height from bin diameter, eave height, grain depth, top shape, and test weight.

Estimate a level cylinder, optionally with a full conical grain peak.

Geometric estimate for a round, flat-bottom bin. A grain peak must fit the roof and usable height; allow for structure, voids and packing.

Grain mass estimate

Defaults are nominal mass assumptions. Enter measured density or leave blank to omit mass.

Grain Bin Capacity Formula

The following formula gives a level cylindrical grain volume. A peaked fill adds a full cone: π × radius² × peak height / 3, with peak height = radius × tan(repose angle). Check that the peak fits the roof and usable height.

C = pi × r² × H
  • Where C is the capacity (ft^3)
  • r is the radius of the bin (ft)
  • H is the height of the bin (ft)

For a level fill, multiply radius squared by π and wall grain depth. The calculator also estimates a full conical peak and optional mass from an editable bulk-density assumption. Test-weight unit changes use same-density arithmetic; they are not crop-specific official grading conversions.

This formula gives you the capacity in cubic feet. To convert into bushels, divide the results by 1.24446.

C = Volume (ft^3) / 1.24446

What is a grain bin capacity?

Definition:

Grain bin capacity is defined as the total volume contained within a cylinder that is used for storing grain.

Most often grain bin capacity is measured in cubic feet or bushels.

How to calculate grain bin capacity?

Example Problem:

The following example problem outlines how to calculate the capacity of a grain bin.

First, determine the radius of the bin. In this example, the radius of the bin is measured to be 10 feet.

Next, determine the height of the bin. In this case, the height of the bin is measured to be 20 feet.

Finally, calculate the grain bin capacity using the formula above:

C = pi*r^2 * H

C = 3.14159*10^2 * 20

C = 6283.18 ft^3

To convert to bushels, divide the result by 1.24446.

C = 6283.18 / 1.24446 ≈ 5048.92 US bushels using these rounded constants. The calculator uses full π and 2150.42 in³ per US bushel, giving 5048.9412 US bushels.