Inventory & Operations
Grain Bin Capacity Calculator
Estimate grain in round, flat-floor bins. Enter measured dimensions, choose the surface shape, then save one bin or a whole worksheet as CSV.
01 · Measured dimensions
Your bins
Changing units converts every entered dimension. Use inside dimensions; enter actual grain depth at the wall.
Bin 1
Across the round bin interior.
Floor to grain at the wall. Zero is valid.
Measure grain depth at the wall from the flat floor, not the empty bin height. Not to scale. Enter the measured diameter and wall depth to see this bin’s volume.
Your entries stay in memory in this tab. Download or copy before leaving; reloading clears the worksheet.
The method
Measure at the wall, then account for the surface
Enter the inside diameter and grain depth at the side wall. A level surface forms a cylinder. For a centered, full-width peak, add a cone; for a centered depression, subtract one. Measure the vertical difference from the wall surface to the center. Use actual grain depth rather than the height of an unfilled bin.
Example 1
A level 20-foot bin
With a 20 ft inside diameter and grain 20 ft deep at the wall, the cylinder holds about 6,283.19 ft³. That is 5,048.94 US standard-volume bushels. The dimensions 6.096 m by 6.096 m describe the same volume.
- Inside diameter
- 20 ft
- Wall grain depth
- 20 ft
- US volume bushels
- 5,048.94 bu
Example 2
The same bin with a 3-foot peak
A full-width cone 3 ft above the wall surface adds about 314.16 ft³. The total is 6,597.34 ft³, or 5,301.39 US volume bushels. The entered wall grain depth remains 20 ft; do not enter 23 ft there and add the peak again.
- Wall depth
- 20 ft
- Peak above wall
- 3 ft
- US volume bushels
- 5,301.39 bu
Example 3
A 3-foot depression instead
Subtract the same cone from the 20 ft by 20 ft cylinder. The result is about 5,969.03 ft³, or 4,796.49 US volume bushels. The center is 17 ft above the floor. A depression deeper than the wall grain depth is outside this flat-floor model.
- Depression below wall
- 3 ft
- Center depth
- 17 ft
- US volume bushels
- 4,796.49 bu
Before you export
Assumptions & limits
- Round bins with a flat floor only. Peak and depression models require a centered cone spanning the whole inside diameter. Hoppers, irregular piles and partial-width cones need another model.
- Results estimate geometric volume from measurements. They do not establish rated capacity, structural limits, usable headroom, remaining capacity or official inventory.
- A US struck bushel is 2,150.42 cubic inches. This worksheet uses that volume convention without packing or moisture corrections; Imperial bushels and rounded farm factors differ.
- Optional test weight estimates mass only. It does not change geometric volume or convert the result into commodity sale bushels. Representative sampling and actual weighing may produce different results.
- Up to 20 bins. Every included bin must have valid geometry for a complete total. CSV retains invalid rows with errors and leaves incomplete totals blank. Missing mass is not zero.
- Labels and measurements stay in this tab. No uploads, analytics or automatic saving. Download the worksheet before closing the page.
Keep in mind
Common mix-ups
Can I use the height to the center?
Use grain depth at the wall in the depth field. Enter the wall-to-center difference separately for a peak or depression. Mixing the two references counts the cone incorrectly.
Why does another grain calculator give different bushels?
Check inside dimensions, the surface reference and the conversion convention. Some farm tools use rounded volume factors or crop-specific adjustments. This result states its US dry-volume basis so you can compare like with like.
Does test weight change the bin volume?
No. The same measured shape occupies the same space. Here test weight only estimates pounds and tonnes from that space; it does not calculate a moisture-adjusted marketing quantity.
How do I total several bins?
Add a labeled row for each bin. The worksheet sums unrounded row volumes. Correct every geometry error for a complete volume total; enter a valid test weight for every row only if you also need a complete mass total.
Sources & method notes
US dry-volume and length conversion definitions. The calculator uses 2,150.42 cubic inches per US struck bushel and 0.3048 metres per foot.
Round-bin geometry and the wall-depth method: add one-third of peak height or subtract one-third of depression depth. Crop packing adjustments and rule-of-thumb peak heights are not applied here.
Background on test weight and the distinction between a volume measurement and commodity weight conventions.
Method and input rules checked: . Engineering validation; no professional specialist review is claimed.