Grain Bin
Calculate grain bin capacity in bushels and cubic feet with our free online grain bin bushel calculator. Get volume, weight, and capacity estimates for your round grain bin with peaked roof and hopper options.
About This Calculator
The Grain Bin Capacity Calculator helps farmers, agronomists, and grain storage operators estimate the storage capacity of round grain bins. By entering the bin diameter, sidewall height, and optional peak and hopper dimensions, you can quickly determine the total volume in cubic feet and bushels, as well as the estimated grain weight for corn, wheat, soybeans, and other commodities.
The calculation uses standard geometric formulas for cylindrical bodies with optional conical peaked roofs and inverted conical hopper bottoms. The body volume is calculated using the formula π × R² × H where R is the radius and H is the sidewall height. A peaked roof adds one-third of the base area times the peak height. To convert cubic feet to bushels, we use the standard agricultural conversion factor of 0.7786 bushels per cubic foot. If you provide the test weight (typically 56 lbs/bu for corn, 60 lbs/bu for wheat and soybeans), the calculator also estimates the total grain weight.
Regional Notes
United States: Grain bin capacities are typically measured in bushels with dimensions in feet. The standard bushel volumes are defined by the US Department of Agriculture. Common test weights are 56 lb/bu for corn, 60 lb/bu for wheat and soybeans, 48 lb/bu for barley, and 32 lb/bu for oats.
India: Grain storage in India commonly uses metric units. Capacity is measured in metric tons (tonnes) and cubic meters. 1 cubic meter equals approximately 28.38 US bushels of corn. The Food Corporation of India (FCI) operates large covered storage facilities and silos for food grain storage in metric units.
United Kingdom: UK grain storage uses both metric tonnes and imperial bushels. A UK bushel differs slightly from a US bushel (1 UK bushel ≈ 1.032 US bushels). Most modern UK grain stores measure capacity in tonnes, with store dimensions typically measured in meters.
Frequently Asked Questions
How do you calculate grain bin capacity?
Calculate the volume of the cylindrical body using π × radius² × sidewall height. Add the peaked roof volume (one-third × π × radius² × peak height) and the hopper volume if present (one-third × π × radius² × hopper height). Convert cubic feet to bushels by multiplying by 0.7786 bushels per cubic foot.
How many bushels does a 24-foot diameter grain bin hold?
A 24-foot diameter grain bin with 16-foot sidewalls and a 6-foot peaked roof holds approximately 5,620 bushels of grain. The body holds about 7,238 cubic feet, the peaked roof adds roughly 905 cubic feet, and the total volume of about 8,143 cubic feet converts to approximately 6,340 bushels at 0.7786 bushels per cubic foot.
What is the conversion factor from cubic feet to bushels?
The standard conversion factor for grain bin calculations is 0.7786 bushels per cubic foot. This accounts for the packing and settling of grain within the bin. One US bushel equals approximately 1.244 cubic feet of volume.
How do you calculate grain weight in a bin?
Multiply the total bushel volume by the test weight of the grain. Common test weights are 56 lbs per bushel for corn and 60 lbs per bushel for wheat and soybeans. For example, 6,340 bushels of corn at 56 lbs/bu equals about 355,040 lbs (177.5 tons).
What is a peaked roof on a grain bin?
A peaked roof on a round grain bin forms a cone shape on top of the cylindrical body. Grain is loaded through a central hatch at the peak and fills the cone by the angle of repose. The peaked roof volume is calculated as one-third of the base area times the peak height.
What is a hopper bottom grain bin?
A hopper bottom grain bin has an inverted cone or pyramid at the base that allows grain to flow out by gravity through a central opening. This eliminates the need for sweeping or auger removal. The hopper volume is calculated as one-third of the base area times the hopper height.
Is the grain bin calculator free to use?
Yes, this grain bin capacity calculator is completely free to use with no registration or login required. You can calculate as many bin configurations as you need for your farm planning.