Grain Storage Calculator
Calculate grain bin capacity in bushels from bin diameter, height, and grain test weight. Plan storage for corn, soybeans, wheat, and more.
Grain Bin Capacity Inputs
Calculate bushels a bin can hold
Diameter of bin
Eave height
Corn: 56, soybeans: 60
Take multiple samples from different field locations and average them for the most accurate results. Avoid border rows and unusual spots.
All calculations use USDA-standard formulas. No registration required, works on mobile, tablet, and desktop.
What Is a Grain Storage Calculator?
A grain storage calculator helps you determine how many bushels of grain a storage bin can hold based on its dimensions. Whether you're planning new bin construction, deciding which bins to fill first, or calculating how much additional storage you need for this year's crop, this tool provides instant, accurate capacity estimates.
Grain bin capacity depends on three factors: bin diameter, eave height (or grain depth), and grain test weight. Standard corn at 56 lb/bu fills differently than high-test-weight corn at 60 lb/bu. This calculator accounts for all three variables.
For bins with peaked grain, add 1/3 of bin diameter × peaking height to total capacity. Most modern bins have levelers, so flat-top calculation is standard.
Grain Bin Capacity Formula
The standard grain bin capacity formula:
Bushels = (π × r² × height) × 0.7786 × (test weight ÷ 56)
Where:
- r = bin radius in feet (diameter ÷ 2)
- height = grain depth in feet
- 0.7786 = conversion factor (1 cu ft = 0.7786 bu at 56 lb/bu)
- test weight = grain test weight in lb/bu
Example
A 30-foot diameter bin filled 24 feet deep with 56 lb/bu corn:
π × 15² × 24 × 0.7786 × (56/56) = 3.14159 × 225 × 24 × 0.7786 = 13,200 bushels
Standard Grain Test Weights
| Grain | Standard Test Weight (lb/bu) |
|---|---|
| Corn | 56 |
| Soybeans | 60 |
| Wheat | 60 |
| Oats | 32 |
| Barley | 48 |
| Grain sorghum | 56 |
| Rye | 56 |
Note: Actual test weight may vary by 1-3 lb/bu from standard. Stress conditions (drought, disease, frost) typically reduce test weight. Excellent grain fill conditions can raise it 2-3 lb/bu.
Grain Storage Best Practices
Cool Grain Quickly
Cool grain to 40°F by November, 30°F by December. Each 10°F drop doubles storage life.
Manage Moisture
Store at 15% or drier for short-term, 13-14% for long-term storage. Wet grain = spoilage.
Aerate Regularly
Run fans 1-2 hours per week to maintain uniform temperature and prevent moisture migration.
Inspect Weekly
Check bin roof for crusting, smell for mustiness, monitor temperature cables. Catch problems early.
Frequently Asked Questions
Everything you need to know about corn yield calculation
Grain bin capacity depends on diameter and height. Use formula: Bushels = π × r² × height × 0.7786 × (test weight ÷ 56). A 30 ft diameter × 24 ft tall bin holds about 13,200 bushels of corn (56 lb/bu). A 48 ft × 32 ft bin holds about 45,000 bushels.
Corn at 15% moisture can be stored up to 1 year if kept cool (under 40°F). At 13-14% moisture, corn stores 2+ years. Above 15.5% moisture, corn should be dried before long-term storage. Always monitor temperature and inspect weekly.
Standard corn test weight is 56 lb/bu. Good corn typically tests 56-60 lb/bu. Test weights below 54 lb/bu may indicate stress during grain fill and may be discounted at the elevator. Above 60 lb/bu is excellent and may earn a premium.
Grain bin cost varies widely: a 30,000-bushel bin costs $50,000-$80,000 installed; a 100,000-bushel bin runs $150,000-$250,000. Add $20,000-$50,000 for fans, heaters, and unloading equipment. Used bins cost 40-60% of new.
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