Grain Bin Capacity Calculator
Wondering if your bin will hold the harvest? This converts bin dimensions to bushel capacity using the standard 0.8036 bushels per cubic foot, including the peaked roof fill.
Formula: cylinder capacity = π × (diameter ÷ 2)² × eave height × 0.8036 bushels/cu ft. A peaked roof that fills to the cone adds about 15-20% (modeled as a cone at ~20% of diameter height). Usable capacity: actual bushels differ by grain test weight (corn 56 lb/bu, soybeans 60, wheat 60) and how completely the bin fills. Check the sticker: manufacturers publish rated capacity charts — use this as a planning estimate and confirm against your bin's nameplate.
FAQ
How many bushels does a 36x21 grain bin hold?
About 17,200 bushels filled to the eave, or roughly 20,000+ with a peaked roof, using 0.8036 bu/cu ft. Check the manufacturer's chart for your exact bin.
How many cubic feet are in a bushel?
One US bushel equals 1.2445 cubic feet, so there are 0.8036 bushels per cubic foot. Multiply bin volume in cubic feet by 0.8036.
Does grain type change bin capacity?
The volume in bushels is the same; what changes is weight (test weight). A bin holds the same number of bushels of corn or soybeans, but a bushel of corn weighs 56 lb and soybeans 60 lb.
Figures are editable example defaults for planning, not guarantees. Crop inputs, prices, and moisture handling vary by farm, region, and year — verify with your local extension service and agronomist.