How we got these numbers (with your inputs)
Enter bin size to see the math step-by-step.
Grain Bin Capacity (Bushels & Weight)
Units: Saved on this device
Results
Bushels: — bu
Weight: — (— )
Volume: —
Fill estimate (from reverse input)
—
Estimates only. Verify before purchasing materials or operating equipment.
How this calculator works
This tool treats the bin as a cylinder plus optional cones (roof and/or hopper), converts volume to U.S. bushels, then applies test weight to estimate grain weight.
Formulas
- Cylinder volume (ft³) = π × (D/2)² × H
- Conical roof / hopper (ft³) = π × (D/2)² × height ÷ 3
- Bushels = total ft³ ÷
1.2445(ft³ per U.S. bushel) - Weight (lb) = bushels × test weight (lb/bu)
- Tons = pounds ÷ 2000
Assumptions & notes
- Geometry assumes a true cylinder and right cones; eave overhangs and roof pitch variations aren’t modeled.
- Moisture shrink reduces calculated bushels by the chosen percent.
- Default test weights reflect common industry values; measured test weight yields the best estimate.
- Unit facts: 1 U.S. bu = 1.2445 ft³ ≈ 35.24 L; 1 lb/bu ≈ 1.287 kg/hl.
Worked example
36 ft diameter, 24 ft straight wall, conical roof 4 ft, corn at 56 lb/bu, no shrink:
- Cylinder: π×18²×24 ≈ 24,429 ft³
- Roof cone: π×18²×4 ÷ 3 ≈ 1,357 ft³
- Total ft³ ≈ 25,786 ft³
- Bushels: 25,786 ÷ 1.2445 ≈ 20,713 bu
- Weight: 20,713 × 56 ≈ 1,160,000 lb (~580 tons)
FAQ
What if my roof is flat? Leave roof height at 0 so only the cylindrical volume is used.
Can I use metric? Yes — toggle at the top. The UI converts ft/m, ft³/m³ and lb/t; test weight switches to kg/hl.
Why don’t my numbers match label capacity? Manufacturer ratings may use different fill levels or safety factors; we use pure geometry.
Where do test weight defaults come from? Common industry values for typical dry grain; adjust to your measured test weight.
Prepared by AgCalculator · Last updated October 27, 2025