Grain Bin - Volume, Bushels, and Weight

A grain bin calculator estimates how many US bushels, cubic feet, cubic meters, pounds, and US short tons a cylindrical or rectangular storage bin will hold based on its diameter or length and width, sidewall height, optional peaked top and hopper bottom, and the test weight of the stored grain.

• • Sizing a new bin purchase: Compare manufacturer capacity charts against expected harvest volume so the new bin matches the farm's typical year.
• • Planning harvest storage: Estimate how much of an expected corn or soybean crop will fit in an existing bin set before the combine starts.
• • Verifying an existing bin's capacity: Recheck a bin that was repaired, re-sided, or fitted with a hopper retrofit against its original nameplate.
• • Converting stored grain to a sale or haul unit: Translate the level in a bin into pounds or US short tons for sale tickets or trucking quotes.

The calculator works for the two shapes most often used on the farm: a cylindrical round bin on a concrete pad and a flat-bottom rectangular bin with or without an internal hopper. The body, optional peaked top, and optional hopper bottom are added together before the cubic-foot total is converted to US bushels, and bushels, cubic feet, cubic meters, pounds, and US short tons are reported side by side.

For matching the same yield to a different size of farm, the corn yield calculator translates a per-acre kernel count into the same bushel figure the bin model expects.

The calculator builds a three-piece geometric model: a straight sidewall, an optional conical peaked top, and an optional conical hopper bottom. Each piece is computed in cubic feet, summed, and converted to bushels using the official US bushel from NIST Handbook 44. A test weight in pounds per bushel is then applied for grain weight in pounds and US short tons.

• R: Radius of a round bin in feet, equal to the diameter divided by 2.
• L, W: Length and width of a rectangular bin in feet.
• H_body: Sidewall height in feet, from the floor to the eave.
• H_top: Height of the optional peaked top in feet. Set to 0 for a flat-topped bin.
• H_hopper: Height of the optional conical hopper bottom in feet. Set to 0 for a flat-floored bin.
• TestWeight: Test weight of the stored grain in pounds per US bushel.

The cone pieces use one-third of the body cross-section per foot of cone height, the same approximation used by Iowa State University Extension. The 0.8036 bushels per cubic foot factor comes from the official US bushel of 2150.42 cubic inches.

According to NIST Guide for the Use of the SI, the US bushel is defined as 2150.42 cubic inches, or 1.2445 cubic feet, so one cubic foot of grain equals 1 / 1.2445 = 0.8036 US bushels, which is the conversion factor used by the calculator.

For an isolated check on the hopper or peaked-top geometry, a cone volume calculator applies the same one-third cone factor to a single frustum.

Four small ideas explain every number the grain bin calculator shows. Once they are clear, the result is straightforward to read and to double-check against a manufacturer chart.

These four definitions matter most when the same bin is loaded with different grains. The bushel count stays the same because a bushel is a fixed volume, but the grain weight in pounds shifts with the test weight.

When the four concepts above need a separate check, a cylinder volume calculator returns the body cross-section times sidewall height for the same round bin in isolation.

Five short steps take the user from a blank form to a trustworthy bushel count, volume, and grain weight.

1. 1 Pick the bin shape: Choose Round for a cylindrical grain bin or Rectangular for a flat-bottom box bin.
2. 2 Enter the dimensions: For a round bin, enter the outside diameter and sidewall height. For a rectangular bin, enter the length, width, and sidewall height. All values are in feet.
3. 3 Add the peaked top and hopper if present: Enter the peaked top height from the eave to the peak and the hopper bottom height from the floor to the apex. Leave both at 0 for a flat-topped, flat-floored bin.
4. 4 Choose the stored grain: Select corn, soybeans, wheat, barley, oats, sorghum, or Custom. The test-weight field fills with the standard test weight in pounds per bushel.
5. 5 Read the result panel: The result panel shows bushel capacity, cubic feet, cubic meters, grain weight in pounds, and grain weight in US short tons. Numbers update in real time as the inputs change.

A 30 ft round bin with a 20 ft sidewall and a 4 ft peaked top used to hold wheat at 60 lb/bu returns about 12,118 bushels, 15,080 cubic feet, 427.0 cubic meters, 727,080 pounds, and 363.5 US short tons.

When a temporary wet bin is rented or an old fuel tank is being repurposed, a tank volume calculator applies the same cylindrical arithmetic to the liquid storage shape.

A purpose-built grain bin calculator saves a trip to the manufacturer chart and gives harvest, sale, and equipment numbers in the units each user actually needs.

• • Matches storage to harvest forecast: Pair the bin capacity with a per-acre yield forecast so the farm has room for the expected crop without renting emergency storage.
• • Compares bins before a purchase: Convert manufacturer diameters and sidewall heights into bushels and tons so candidate bins can be ranked on a single capacity figure.
• • Converts bushels to tons for sales and trucking: Use the test-weight preset to skip the bushel-to-ton math by hand and match the numbers used on scale tickets and barge contracts.
• • Plans dryer and aeration capacity: Match the bin's cubic-foot and bushel volume to fan and heater ratings, which are still quoted in cubic feet per minute per bushel.
• • Supports insurance and tax records: Document the on-farm storage capacity in bushels and pounds so insurance riders and property tax assessments can use the same figure the operator uses day to day.

For farms that pair grain storage with livestock planning, the cattle per acre calculator applies the same density-driven approach to stocking decisions on the same harvested acres.

Three bin-specific variables and one commodity-specific variable drive the result, and two limitations remind the user when to double-check the number against a real measurement.

• • The calculator does not adjust for grain compaction at deep depths, which can reduce the volume of stored grain by 1% to 3% in bins filled above 30 ft of sidewall.
• • Test weights vary by variety, season, and moisture content, so a custom test weight should be used whenever the actual scale ticket or grade certificate is available.

According to USDA AMS Grain Standards, US No. 1 shelled corn tests at least 56 pounds per bushel, US No. 1 soybeans test at least 60 pounds per bushel, and US No. 1 hard red winter wheat tests at least 60 pounds per bushel, and the calculator uses these test weights as the default for each preset.

According to Iowa State University Extension, peaked grain bin tops and hopper bottoms should be modeled as one-third of the body cross-section per foot of cone height, which is the same geometric approximation used by this calculator.

Once the bin model and the field model agree on a bushel target, the acres per hour calculator helps schedule the combine and the grain cart so the bin can be filled in the harvest window.