Grain Bin Capacity Calculator
Estimate grain volume in a flat-bottom round bin using inside diameter, grain depth at the wall, and an optional grain peak. Get cubic feet and approximate US volume bushels. Free, no signup needed.
How to calculate round grain-bin capacity
Volume (ft³) = π × (inside diameter ÷ 2)² × (grain depth at the wall + peak height ÷ 3). All dimensions are in feet. US volume bushels = cubic feet × 1,728 ÷ 2,150.42.
Use 0 for peak height when grain is level. This assumes a flat usable floor and a centered cone-shaped peak. It does not support hopper-bottom bins, off-center piles, or depressions.
Volume is not saleable grain weight
This is a geometric planning estimate, not certified capacity or trade bushels. Packing, moisture, test weight, settlement, headspace, drying floors and equipment affect actual usable space or contents. Follow manufacturer fill and load limits. Never enter a grain bin to measure.
Geometry follows Iowa State University Extension. The US volume bushel definition (2,150.42 cubic inches) comes from the USDA ERS glossary. Neither source certifies this tool.
Keep grain records together
Create a CropBuddy farm to organize grain storage records. This calculator does not save inventory entries or transfer measurements. Free during the current public beta. No payment card required.