How this calculator works
The filled sidewall section is a cylinder or rectangular prism. A pointed peak or full pointed hopper contributes one-third of footprint area times height. A curved top is modelled as a spherical cap, not an arbitrary roof profile. US dry bushels are physical volume here, using 0.03523907016688 m3 per bushel. Stored mass comes from measured bulk density, not the commodity standard weight per commercial bushel. Packing, wall irregularities and moisture changes are excluded.
Formula
Level volume = footprint area × depth. Cone or pyramid = area × height/3. Spherical cap = pi × h × (3r2 + h2)/6. Mass = total volume × bulk density.
Worked example
A rectangular bin 10 m × 5 m filled 4 m deep holds 200 m3 and 150000 kg at 750 kg/m3. A 2 m diameter round bin with 3 m sidewall fill and two 1 m pointed additions holds about 11.51917 m3.
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Frequently asked questions
Does the whole roof contain grain?
Not necessarily. Enter the actual grain peak, and choose level fill when there is no peak.
Are these commercial bushels by weight?
No. The bushel output is a physical US dry volume. Use grain conversion for commodity-specific mass conventions.
Can I count an empty hopper?
Select No if it is empty. The Yes option assumes the pointed hopper is completely filled; partial hopper filling needs a separate geometry calculation.