How do you calculate grain bin capacity in bushels?

For a round bin, multiply the diameter squared by the grain depth by 0.628. A bin with diameter squared of 1,296 (a 36 ft bin) filled 24 ft deep holds about 19,533 bushels at level fill.

Why is the round-bin factor 0.628?

It combines the cylinder area constant (pi over 4, about 0.7854) with the conversion from cubic feet to bushels (1 bushel is about 1.2445 cu ft). The math collapses to roughly 0.628 bushels per foot of depth per square foot of diameter-squared.

Does this include the peak of grain at the top?

No, this is a level-fill estimate. A center-fill spout builds a cone that adds bushels; for a full accounting, calculate the cone separately and add it to the level-fill number.

How do I find diameter squared for my bin?

Multiply the bin's diameter by itself. A 36 ft bin is 36 x 36 = 1,296; a 27 ft bin is 27 x 27 = 729. Enter that product, not the raw diameter.

What is the pack adjustment for?

Grain settles and compacts under its own weight, and heavy test-weight grain packs more bushels into the same volume. Use 1.0 for a simple estimate, or a value above 1.0 to credit packing and high test weight.

How many bushels is a 36-foot bin?

It depends on fill depth. At 24 ft of level grain, a 36 ft bin holds about 19,533 bushels; capacity rises directly with depth, so a full-height fill holds proportionally more.

Agriculture, Soil, Fertilizer & Farm Operations calculator

Grain Bin Capacity Calculator

This calculator estimates how many bushels of grain a round bin holds at a given level fill, which is the number a farmer needs at harvest to know whether the crop will fit, how to route trucks, and what to sell versus store. It uses the standard round-bin shortcut, diameter squared times depth times 0.628, that converts a cylinder's cubic feet directly into bushels. Corn, soybean, and wheat producers rely on it to plan bin space, verify auger and dryer scheduling, and estimate on-farm inventory for marketing. A pack and test-weight adjustment lets you refine the level-fill estimate for grain that settles or runs heavier than standard.

What this calculator does

Estimate round grain bin capacity from bin diameter squared, grain depth, and the standard bushel conversion factor.
Use it to check whether a bin can hold a field, delivery, or drying batch before harvest starts.
It computes the level-fill bushel capacity of a round bin from diameter squared, usable grain depth, and the 0.628 round-bin conversion, with an optional pack adjustment.

Formula used

Grain bin capacity = diameter squared x grain depth x 0.628 x pack adjustment

Inputs explained

Bin diameter squared: Multiply bin diameter by itself before entering.
Usable grain depth: Use level-fill grain depth after subtracting floor, sump, or headspace limits.
Round-bin bushel conversion: Use 0.628 for approximate bushels in a round bin.
Pack and test-weight adjustment: Use 1 for a simple estimate or adjust for pack, peak, or test weight.

How to use the result

Use it at harvest to check whether a bin will hold a field's yield, to estimate stored inventory, or to plan drying and unload logistics.
It estimates a level fill only, it does not add the extra bushels in a coned peak from a center-fill spout, and it assumes standard test weight unless you adjust for it.

Current U.S. benchmarks

U.S. manufacturing runs at 75.6% of capacity (Federal Reserve, Jun 2026). New factory orders are up 2.3% year over year (Census).
Industrial natural gas averages $4.9 per Mcf (EIA, Apr 2026), down 7.7% from a year earlier, with industrial electricity at 8.66 cents per kWh. Process heating and refrigeration budgets track both.

Common questions

How do you calculate grain bin capacity in bushels? For a round bin, multiply the diameter squared by the grain depth by 0.628. A bin with diameter squared of 1,296 (a 36 ft bin) filled 24 ft deep holds about 19,533 bushels at level fill.
Why is the round-bin factor 0.628? It combines the cylinder area constant (pi over 4, about 0.7854) with the conversion from cubic feet to bushels (1 bushel is about 1.2445 cu ft). The math collapses to roughly 0.628 bushels per foot of depth per square foot of diameter-squared.
Does this include the peak of grain at the top? No, this is a level-fill estimate. A center-fill spout builds a cone that adds bushels; for a full accounting, calculate the cone separately and add it to the level-fill number.
How do I find diameter squared for my bin? Multiply the bin's diameter by itself. A 36 ft bin is 36 x 36 = 1,296; a 27 ft bin is 27 x 27 = 729. Enter that product, not the raw diameter.
What is the pack adjustment for? Grain settles and compacts under its own weight, and heavy test-weight grain packs more bushels into the same volume. Use 1.0 for a simple estimate, or a value above 1.0 to credit packing and high test weight.

Last reviewed 2026-05-12.