Grain Bin Bushel Capacity Calculator
Calculate grain bin bushel capacity from diameter, height and test weight, with the standard bushel volume and a test-weight adjustment.
How This Calculation Works
Bin volume in cubic feet equals pi times the radius squared times the height. Dividing by 1.2445 cubic feet per bushel gives the bushel capacity at standard test weight. Adjust for the actual test weight by multiplying by the actual divided by the standard.
Field Calibration & Rate Reference Chart
| Area | Square feet | Acres | Square field side |
|---|---|---|---|
| 1,000 sq ft | 1,000 | 0.023 | 32 ft |
| 5,000 sq ft | 5,000 | 0.115 | 71 ft |
| 10,000 sq ft | 10,000 | 0.230 | 100 ft |
| 0.25 acre | 10,890 | 0.250 | 104 ft |
| 0.5 acre | 21,780 | 0.500 | 148 ft |
| 1 acre | 43,560 | 1.000 | 209 ft |
| 5 acres | 217,800 | 5.000 | 467 ft |
| 10 acres | 435,600 | 10.000 | 660 ft |
| 40 acres | 1,742,400 | 40.000 | 1,320 ft |
| 100 acres | 4,356,000 | 100.000 | 2,087 ft |
Common Questions
How do I calculate grain bin capacity in bushels?
Calculate the bin volume in cubic feet as pi times the radius squared times the height, then divide by 1.2445 cubic feet per bushel. A 30-foot diameter bin 20 feet tall holds about 11,300 bushels. Adjust for test weight.
How many cubic feet are in a bushel?
A standard bushel is 1.2445 cubic feet, based on the Winchester bushel. That figure converts bin volume to bushels. Test weight changes the actual bushels for a given volume.
Does test weight change bin capacity?
Yes, a higher test weight means more pounds per bushel, so the same volume holds more weight but the bushel count is based on volume. Adjust the bushel figure by the ratio of actual to standard test weight. Light grain fills the same space with fewer pounds.
How much headspace should a grain bin have?
Leave enough headspace for aeration, grain movement and the fill spout, often a foot or more below the eaves. Overfilling can damage the roof and block aeration. Check the bin's rated capacity with the manufacturer.