Grain Bin Capacity
Calculator

Capacity is primarily a function of the bin's internal volume (diameter and height, or eave height plus the cone at the peak and hopper at the bottom) combined with the test weight of the specific grain being stored, since different grains pack at different densities.

Test weight (bulk density) varies by grain type — wheat is generally denser than corn per unit volume — so a bin's fixed volume translates into a different tonnage depending on which grain fills it. Always use the correct test weight for your specific crop and moisture content.

Yes — wetter grain has a slightly different bulk density than dry grain of the same type, and it also tends to settle and compact differently during storage, so capacity estimates are most accurate when based on the grain's actual moisture and test weight at fill time.

No — practical usable capacity is normally less than the theoretical full-to-the-roof volume, since headspace is needed for aeration equipont and to avoid grain contacting the roof structure. Manufacturers typically publish a rated capacity that already accounts for this.

The conical peak and any hopper bottom add or subtract volume compared to a simple cylinder calculation, so an accurate capacity figure treats the cylindrical body, the peak cone, and (if present) the hopper cone as separate volumes to be summed. Ignoring the peak cone alone can meaningfully understate capacity on tall bins.