A grain bin volume calculator converts bin dimensions into storage capacity measured in bushels. Whether you are planning a new bin purchase, estimating how much grain you can store after harvest, or checking how full your current bin is, this tool calculates volume for round bins, rectangular flat storage, and peaked grain using standard conversion factors. Enter your bin diameter, eave height, and optional peak height to get instant results in cubic feet, bushels, and estimated weight.
Bin Volume & Capacity
Inside diameter of the bin
Height to the eave or grain depth
Common Round Grain Bin Sizes
| Diameter | Rings | Eave Height | Capacity (bu) | Corn (tons) |
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How to Use the Grain Bin Volume Calculator
Knowing your grain bin capacity in bushels is essential for harvest planning, grain marketing, and storage management. Whether you are filling bins after harvest, estimating how much grain you can store, or measuring how much is left in a partially full bin, this grain bin volume calculator gives you fast, accurate results using standard industry conversion factors.
Step 1: Choose Your Bin Shape
Select "Round Bin" for standard round steel grain bins, which are the most common on-farm storage. Select "Rectangular" for flat storage buildings, machine sheds converted to grain storage, or any rectangular structure. Each shape uses a different volume formula to calculate total cubic feet.
Step 2: Enter Bin Dimensions
For round bins, enter the inside diameter and eave height in feet. The diameter is the distance across the inside of the bin at ground level. The eave height is the distance from the floor to where the roof begins. For rectangular bins, enter the inside length, width, and grain depth. All measurements should be in feet.
Step 3: Add Peaked Grain (Optional)
If grain is piled above the eave in a cone shape, toggle on "Peaked grain" and enter the peak height. This is the distance from the top of the eave to the highest point of the grain cone. The calculator uses the cone volume formula to add this extra capacity. A typical peak adds 5-8% to the total bin capacity.
Step 4: Select Grain Type
Choose the grain you are storing to get an accurate weight estimate. Different grains have different standard test weights: corn and sorghum weigh 56 pounds per bushel, while soybeans and wheat weigh 60 pounds per bushel. Oats are much lighter at 32 pounds per bushel. The grain bin bushel calculator uses these standard USDA test weights to convert bushels to pounds and tons.
Step 5: Review Your Results
Click "Calculate Capacity" to see total volume in cubic feet, capacity in bushels, estimated weight in pounds, and weight in short tons. The detailed breakdown shows how the calculation was performed, including separate volumes for the cylinder and cone portions. Use the common bin sizes reference table to quickly compare standard bin dimensions and their capacities.
Measuring a Partially Full Bin
To find out how much grain is currently in a partially full bin, measure the grain depth rather than the full eave height. Enter the depth from the bin floor to the top of the grain level as the "Eave Height." If the grain has a peak in the center, add the peak height separately. This gives you the current contents rather than total capacity, which is useful for inventory management and grain marketing decisions.
Frequently Asked Questions
Is this grain bin volume calculator free to use?
Yes, the grain bin volume calculator is completely free with no signup, no account, and no hidden fees. All calculations run locally in your browser so your farm data stays private on your device.
Is my data safe when I use this tool?
Absolutely. Every calculation runs locally in your browser using client-side JavaScript. No bin dimensions, grain quantities, or any other data are ever sent to a server or stored anywhere.
How do I convert cubic feet to bushels?
One bushel equals 1.2445 cubic feet. To convert cubic feet to bushels, divide the total cubic feet by 1.2445. This calculator handles the conversion automatically when you enter your bin dimensions.
How do I measure grain depth for a partially full bin?
Use the 'How full is my bin?' mode and enter the current grain depth instead of the full eave height. For peaked grain, measure from the bin floor to the eave line, then separately measure the peak height above the eave. The calculator will compute the total volume accurately.
What is the standard bushel weight for different grains?
Standard test weights are: corn at 56 lbs per bushel, soybeans and wheat at 60 lbs per bushel, oats at 32 lbs per bushel, barley at 48 lbs per bushel, and grain sorghum at 56 lbs per bushel. These are USDA standard weights used for trade.
How accurate is the peaked grain calculation?
The peaked grain calculation uses the cone volume formula (one-third times pi times radius squared times peak height). This provides a good estimate for a symmetrical cone shape. In practice, grain peaks are rarely perfectly symmetrical, so actual capacity may vary by 2-5% from the calculated amount.
What do ring counts mean for grain bin sizing?
Grain bins are built from corrugated steel rings, typically 32 inches (2.67 feet) tall each. A 5-ring bin has an eave height of about 13.3 feet, a 7-ring bin about 18.7 feet, and an 8-ring bin about 21.3 feet. The common sizes table in this calculator shows standard ring counts and their corresponding eave heights.
Can I use this calculator for flat-bottom storage buildings?
Yes. Use the rectangular bin mode and enter the length, width, and grain depth of your flat storage building. The calculator will compute the volume in cubic feet and convert to bushels. This works for machine sheds, flat storage buildings, and any rectangular grain storage.