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Grain Bin Capacity Calculator - Bushels by Diameter, Height & Commodity

Calculate level fill, peaked fill, and partial fill volumes for flat-bottom and hopper-bottom bins

Enter your bin diameter, eave height, roof pitch, and commodity to calculate total bushel capacity with peaked and level fill volumes. Supports flat-bottom and hopper-bottom bins with accurate cone geometry. Includes weight estimates by commodity and partial fill calculations for inventory checks.

Pro Tip: Peaked fill adds 15–25% capacity over level fill on most bins - but only if your spreader distributes grain evenly. Uneven peaks can create dangerous sidewall pressure.

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Grain Bin Capacity Calculator

How It Works

  1. Enter Bin Dimensions

    Input diameter (feet), eave height (feet), and select your bin type (flat bottom or hopper bottom). For hopper bins, enter the hopper angle.

  2. Select Commodity

    Choose corn, soybeans, wheat, oats, barley, sorghum, sunflowers, or rice. Each has a standard test weight and angle of repose that affects peaked fill volume.

  3. Review Capacity Results

    See level fill bushels, peaked fill bushels, weight in tons, and use the partial fill slider to estimate current inventory at any grain depth.

Built For

  • Farmers estimating storage needs before harvest
  • Grain elevator operators planning bin assignments
  • Insurance adjusters verifying stored grain quantities
  • Equipment dealers sizing bins for customers

Assumptions

  • Bin dimensions are nominal manufacturer values; wall corrugation thickness is not deducted from diameter
  • Grain is uniformly distributed across the bin cross-section (assumes use of a grain spreader for peaked fill)
  • Angle of repose values follow ASABE EP433 standard commodity data
  • Test weights use USDA FGIS official standards (e.g., corn at 56 lb/bu, soybeans at 60 lb/bu)
  • Hopper bottom geometry assumes a true cone with uniform sidewall angle
  • Roof clearance is sufficient to allow full peak formation above the eave line
  • No dockage, foreign material, or broken kernels affecting bulk density

Limitations

  • Does not account for compaction from grain depth (tall bins increase bulk density at the bottom)
  • Wall corrugation reduces effective diameter by 1-3 inches depending on manufacturer profile
  • Peaked fill volume assumes ideal cone geometry that may not form with off-center fill or uneven discharge
  • Does not calculate structural loads — use manufacturer load charts for foundation and sidewall design
  • Partial fill estimates assume a level grain surface, not the irregular profiles common during unloading
  • Not applicable to flat storage buildings, grain bags, or non-cylindrical structures

References

  • ASABE EP433 — Loads Exerted by Free-Flowing Grain on Bins (angle of repose and bulk density data)
  • USDA FGIS — United States Standards for Grain (official test weights by commodity)
  • Midwest Plan Service MWPS-13 — Grain Drying, Handling and Storage Handbook
  • ASABE D241.4 — Density, Specific Gravity, and Mass-Moisture Relationships of Grain for Storage
  • University of Kentucky AEN-80 — Grain Storage Bins: Estimating Bushels of Grain in Round Bins
  • Sukup Manufacturing / GSI / Brock — Bin capacity calculation methodology and rated capacity tables

Frequently Asked Questions

The calculator uses standard geometric formulas (cylinder + cone) with USDA standard test weights. Results typically match manufacturer rated capacity within 2-3%. Differences arise from wall corrugation thickness, floor slope, and actual vs. nominal dimensions.
Yes. The cone of grain above the eave can add 15-25% depending on bin diameter, roof clearance, and the commodity's angle of repose. Corn (25° angle of repose) peaks less than soybeans (29°). But peaked fill only counts if your bin has adequate roof clearance and a grain spreader for even distribution.
USDA standard test weights: corn at 56 lb/bu, soybeans at 60 lb/bu, wheat at 60 lb/bu, oats at 32 lb/bu, barley at 48 lb/bu, sorghum at 56 lb/bu. Actual test weights vary by year and region.
Disclaimer: Capacity estimates use standard geometric formulas and USDA test weights. Actual capacity varies with bin construction, grain condition, and fill method. Do not use for structural loading calculations.

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