Grain Bin Capacity Calculator
Bushel capacity of a round grain bin from diameter and grain depth
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Quick summary
Enter your bin's diameter, the depth of grain, and any coned peak to get capacity in cubic feet and bushels. A 30-ft bin with 20 ft of level grain holds about 14,137 ft³ — roughly 11,360 bushels (1 bushel = 1.2445 ft³). A peaked pile adds a cone of volume on top. Because volume grows with the square of diameter, a wider bin holds disproportionately more.
Reviewed by Simple Calculators TeamLast reviewed
How to use this calculator
- Enter the inputs requested by the calculator.
- Choose the units or options that match your situation and review the assumptions.
- Run or update the calculation to see the result.
- Review the result, breakdown, and formulas shown on the page.
- Check the inputs, units, dates, and limitations before saving or sharing the result.
Frequently asked questions
How do I calculate bushels in a round grain bin?
Find the cylinder volume — π × radius² × grain depth — then multiply by 0.8036 bushels per cubic foot. A 30-ft-diameter bin (15-ft radius) with 20 ft of grain is π × 15² × 20 ≈ 14,137 ft³ × 0.8036 ≈ 11,360 bushels. Add a cone for any peaked grain on top. This calculator does both.
How many cubic feet are in a bushel?
One bushel equals 1.2445 cubic feet, so each cubic foot holds about 0.8036 bushels. That conversion turns a bin's volume into grain capacity. It's a volumetric standard; actual bushels stored shift slightly with grain type, moisture, and how tightly the grain packs.
How do I account for a peaked (coned) top?
When grain is filled above the eave it forms a cone. Its volume is ⅓ × π × radius² × peak height — a third of a cylinder of the same height. Enter the peak height and the calculator adds those bushels to the level-grain capacity.
Why does a bigger-diameter bin hold so much more?
Because volume depends on the square of the radius. Doubling the diameter quadruples the floor area and thus the capacity at the same depth. That's why a modest increase in bin diameter yields a large jump in bushels — worth weighing when planning storage.
Key terms
- Bushel
- A volume unit for grain; 1 bushel = 1.2445 ft³ (≈ 0.8036 bu/ft³).
- Grain Depth
- The height of grain in the bin — not the bin height — used for capacity.
- Coned Peak
- The cone of grain above the eave; adds ⅓ × base × height of volume.
Methodology, sources & limitations
This page shows the formula, assumptions, and limitations used for this estimate. Rates, thresholds, and other time-sensitive inputs can change, so verify them against the relevant official source before relying on a result.
For our review approach and the primary sources we consult, see the methodology and source policy. If you spot an outdated figure or formula, please contact us with a correction.