Grain Bin Calculator

Find grain bin storage capacity in cubic feet, bushels, and tons from bin diameter and fill height.

🌾 Grain Bin Calculator
ft
ft

Flat-bottom bin: capacity is the cylinder volume only.

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Bushels
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Volume
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Weight
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Weight (lb)
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Step-by-step working

🌾 What is the Grain Bin Calculator?

The grain bin calculator finds how much grain a cylindrical storage bin can hold, in cubic feet, bushels, and tons, from the bin's diameter and the depth of grain in it. Farmers and grain elevator operators use it to plan storage before harvest, check a bin's remaining capacity mid-season, or estimate the weight of grain in a bin for insurance, loan collateral, or hauling logistics.

Real bins come in two common bottom shapes. A flat-bottom bin is a plain cylinder, so its capacity is simply the cross-section area times the fill height. A cone-bottom (hopper-bottom) bin has an inverted cone welded beneath the cylinder, which both adds extra storage volume and lets grain gravity-flow to a single center outlet without an internal sweep auger. This calculator supports both.

A common source of confusion is entering the bin's radius instead of its diameter, since most bin nameplates and spec sheets quote diameter, this calculator asks for diameter and halves it internally. Another is forgetting that fill height refers only to the straight-walled cylindrical section, the cone-bottom hopper's own height is a separate input in Cone Bottom mode.

This calculator is useful for grain producers, elevator staff, and agricultural students who need a fast, correct bushel and tonnage figure without working through the cylinder-and-cone geometry and the bushel conversion by hand.

📐 Formula

V  =  πr²H  +  (1/3)πr²hc
r = bin radius (diameter ÷ 2), ft
H = fill height in the cylindrical section, ft
hc = cone (hopper) height, ft (0 for flat-bottom bins)
Bushels = V ÷ 1.2444 (standard U.S. Winchester bushel, per NIST Handbook 44)
Weight = bushels × test weight (lb/bu), then ÷ 2,000 for short tons
Example: D=30 ft, H=20 ft, flat bottom, corn: V=14,137.2 ft³, 11,360.6 bu, 318.10 tons.

📖 How to Use This Calculator

Steps

1
Choose flat-bottom or cone-bottom - Select the mode matching your bin's construction.
2
Enter diameter and fill height - In feet, plus cone height if applicable.
3
Select your grain type - Corn, soybeans, wheat, oats, or barley, to apply the correct test weight.
4
Read capacity in bushels and tons - See cubic feet, bushels, and tons, with a fill-height chart.

💡 Example Calculations

Example 1 - Flat-bottom bin of corn

1
Diameter 30 ft, fill height 20 ft, flat bottom, corn (56 lb/bu)
2
r = 15 ft, area = π×15² = 706.86 ft², V = 706.86×20 = 14,137.2 ft³
3
Bushels = 14,137.2 ÷ 1.2444 = 11,360.6 bu; weight = 11,360.6×56 = 636,195 lb = 318.10 tons
Capacity = 11,360.6 bu (318.10 tons)
Try this example →

Example 2 - Cone-bottom bin of soybeans

1
Diameter 18 ft, sidewall height 12 ft, cone height 5 ft, soybeans (60 lb/bu)
2
r = 9 ft, area = π×9² = 254.47 ft², cylinder V = 3,053.6 ft³, cone V = (1/3)×254.47×5 = 424.1 ft³
3
Total V = 3,477.7 ft³; bushels = 3,477.7 ÷ 1.2444 = 2,794.7 bu; weight = 83.84 tons
Capacity = 2,794.7 bu (83.84 tons)
Try this example →

Example 3 - Flat-bottom bin of wheat

1
Diameter 24 ft, fill height 16 ft, flat bottom, wheat (60 lb/bu)
2
r = 12 ft, area = π×12² = 452.39 ft², V = 452.39×16 = 7,238.2 ft³
3
Bushels = 7,238.2 ÷ 1.2444 = 5,816.6 bu; weight = 174.50 tons
Capacity = 5,816.6 bu (174.50 tons)
Try this example →

❓ Frequently Asked Questions

How do you calculate the capacity of a grain bin?+
Multiply the cylinder's cross-section area (pi times radius squared) by the fill height to get cubic feet, then divide by 1.2444 to convert to bushels. If the bin has a cone-bottom hopper, add one-third times area times cone height before converting.
How many cubic feet are in a bushel?+
One U.S. bushel equals 1.2444 cubic feet (2,150.42 cubic inches), this is the standard Winchester bushel used for grain storage and trade in the United States.
How do I convert bushels to tons?+
Multiply bushels by the grain's standard test weight in pounds per bushel (56 for corn, 60 for soybeans and wheat, 32 for oats, 48 for barley), then divide by 2,000 to get short tons.
What is the formula for a cone-bottom grain bin?+
Total volume equals the cylinder volume (pi times radius squared times sidewall height) plus the cone volume (one-third times pi times radius squared times cone height), then divide the sum by 1.2444 to get bushels.
Why is my bin's actual capacity different from the calculated value?+
This calculator assumes a level fill to the eave line and does not add the peaked cone of grain that naturally forms above it during filling, nor does it subtract volume lost to bin sweep augers, ladders, or stiffener ribs.
How much does a full grain bin weigh?+
Weight depends on grain type and moisture. For corn at standard test weight (56 lb/bu), a bin holding 10,000 bushels weighs roughly 280 tons; the same volume of soybeans (60 lb/bu) weighs roughly 300 tons.
What is a standard test weight for corn?+
Corn's standard test weight is 56 pounds per bushel at 15.5% moisture, per USDA grain grading standards. Actual test weight can vary somewhat with moisture content and grain condition.
Does bin diameter or height affect capacity more?+
Diameter matters more, since cylinder volume scales with the square of the radius but only linearly with height. Doubling the diameter roughly quadruples capacity, while doubling the height only doubles it.
What's the difference between flat-bottom and cone-bottom bins?+
A flat-bottom bin stores grain only in the cylindrical section and needs a separate unloading system, while a cone-bottom (hopper-bottom) bin has an inverted cone at the base that adds extra storage volume and lets grain gravity-flow to a single center outlet.
Can I use this calculator for wheat or oats instead of corn?+
Yes, select your grain type from the dropdown, the calculator automatically applies the correct standard test weight (60 lb/bu for wheat, 32 lb/bu for oats) when converting bushels to tons.
Tags: Grain Bin Calculator Bushel Calculator Grain Storage Capacity Cone Bottom Bin Calculator Formula Free Online

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How do you calculate the capacity of a grain bin?

Multiply the cylinder's cross-section area (pi times radius squared) by the fill height to get cubic feet, then divide by 1.2444 to convert to bushels. If the bin has a cone-bottom hopper, add one-third times area times cone height before converting.

How many cubic feet are in a bushel?

One U.S. bushel equals 1.2444 cubic feet (2,150.42 cubic inches), this is the standard Winchester bushel used for grain storage and trade in the United States.

How do I convert bushels to tons?

Multiply bushels by the grain's standard test weight in pounds per bushel (56 for corn, 60 for soybeans and wheat, 32 for oats, 48 for barley), then divide by 2,000 to get short tons.

What is the formula for a cone-bottom grain bin?

Total volume equals the cylinder volume (pi times radius squared times sidewall height) plus the cone volume (one-third times pi times radius squared times cone height), then divide the sum by 1.2444 to get bushels.

Why is my bin's actual capacity different from the calculated value?

This calculator assumes a level fill to the eave line and does not add the peaked cone of grain that naturally forms above it during filling, nor does it subtract volume lost to bin sweep augers, ladders, or stiffener ribs.

How much does a full grain bin weigh?

Weight depends on grain type and moisture. For corn at standard test weight (56 lb/bu), a bin holding 10,000 bushels weighs roughly 280 tons; the same volume of soybeans (60 lb/bu) weighs roughly 300 tons.

What is a standard test weight for corn?

Corn's standard test weight is 56 pounds per bushel at 15.5% moisture, per USDA grain grading standards. Actual test weight can vary somewhat with moisture content and grain condition.

Does bin diameter or height affect capacity more?

Diameter matters more, since cylinder volume scales with the square of the radius but only linearly with height. Doubling the diameter roughly quadruples capacity, while doubling the height only doubles it.

What's the difference between flat-bottom and cone-bottom bins?

A flat-bottom bin stores grain only in the cylindrical section and needs a separate unloading system, while a cone-bottom (hopper-bottom) bin has an inverted cone at the base that adds extra storage volume and lets grain gravity-flow to a single center outlet.

Can I use this calculator for wheat or oats instead of corn?

Yes, select your grain type from the dropdown, the calculator automatically applies the correct standard test weight (60 lb/bu for wheat, 32 lb/bu for oats) when converting bushels to tons.

📌 Quick Tips

💡Measure diameter, not radius, the calculator halves it for you, entering radius by mistake roughly quadruples the reported capacity.
💡Fill (sidewall) height is the depth of grain in the straight cylindrical wall section only, the cone-bottom hopper volume is added separately in Cone Bottom mode.
💡The 1.2444 cubic-foot-per-bushel figure is the legal U.S. Winchester bushel (2,150.42 cubic inches), the same conversion used on USDA grain storage worksheets.
💡Test weight varies by grain and even by crop year, use your actual scale-house test weight for the most accurate tonnage instead of the standard defaults if you have it.
💡Bins are rarely filled perfectly level, the peaked cone of grain above the eave line is not included in this calculator, treat the result as usable capacity to the eave.