Grain Bin Calculator (Bushels and Tons)
Bushels and tons of corn, soybeans, wheat or other grain in a round bin, with a level or peaked top.
Bushels = π × r² × depth ÷ 1.2445 (cu ft per bushel), plus a cone of π × r² × peak height ÷ 3 if peaked. A 30 ft bin with 20 ft of corn holds 14,137 cu ft ÷ 1.2445 = 11,360 bu levelled, or about 12,560 bu with a full peak.
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How to use it
- Enter the bin diameter and the depth of the level part of the grain.
- Choose a levelled top, a full peak, or a measured peak height.
- Pick the grain and read bushels, tons and value.
What you enter
- Bin diameter
- Grain depth
- Top shape
- Grain type
- Price (optional)
What you get
- Bushels
- Tons
- Peak bushels
- Value
Formula
V = πr²h + πr²h_peak/3 | bu = V / 1.2445 | tons = bu × test weight / 2,000
Worked example
Input: 30 ft bin, 20 ft corn, full peak
Result: About 12,565 bu (352 tons)
The peak alone holds about 1,200 bushels.
Questions
How many bushels are in a grain bin?
Multiply 3.1416 × radius² × grain depth in feet to get cubic feet, then multiply by 0.8036 (or divide by 1.2445) for bushels.
How do I account for the peak?
A peaked top is a cone: π × r² × peak height ÷ 3. A full peak at corn's 23° angle of repose in a 30 ft bin rises about 6.4 ft and adds roughly 1,200 bushels.
How many pounds are in a bushel?
Standard test weights: shelled corn and sorghum 56 lb, soybeans and wheat 60 lb, barley 48 lb, oats 32 lb.
Why is my measured inventory different?
Grain compacts under its own weight in tall bins (several percent), and moisture and fines change bulk density.
Limitations
- Ignores compaction and the hopper of hopper-bottom bins.
References
- Hellevang KJ (2013) Grain Drying, Handling and Storage Handbook. North Dakota State University Extension.
Related reading
- Livestock Feed Storage and Preservation: Hay, Silage, and Grain Management
- Beef Cattle Feed Storage Design: Silos, Bunkers, and Sheds
- Feeding Grain to Cattle: Ration Formulation and Transition Strategies
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All free tools · By Dr. Zubair Khalid, DVM, MS, PhD.