Silage Tonnage Calculator
Estimate the tons of silage in a bunker or pile from its length, width, average depth and packed density.
How it works
Volume = length × width × depth · Tons = volume × density ÷ 2,000
Silage inventory is volume times packed density. The volume of a bunker or drive-over pile is its footprint times the average settled depth, and density is the make-or-break number — a well-packed bunker of corn silage runs around 40–48 lbs per cubic foot as-fed, while a loose, under-packed pile can be far lighter and spoil faster. Multiplying volume by density and converting to tons tells you how much feed you have banked and how long it will last.
Worked example
A bunker 60 ft long, 30 ft wide and 8 ft of average depth is 14,400 ft³. At 44 lbs/ft³ that is 633,600 lbs, or 633,600 ÷ 2,000 ≈ 316.8 tons of silage.
Frequently asked questions
How do I estimate packed density?
As-fed density depends on packing tractor weight, layer thickness, chop length and dry matter. Well-managed bunkers reach 15–18 lbs of dry matter per cubic foot, which at 32–35% dry matter is roughly 44–50 lbs/ft³ as-fed. For an inventory audit, a probe or measured feed-out over time is more accurate than a nominal figure.
Does this handle sloped bunker faces?
It assumes a rectangular block, so use the average depth across the pile to absorb sloped ends and a rounded top. For a triangular drive-over pile, estimate the cross-sectional area and multiply by length instead.
Is this as-fed tons or dry matter tons?
As-fed, because the density is an as-fed figure. To get dry-matter tons, multiply the result by the silage dry-matter percentage — 316 as-fed tons at 34% dry matter is about 107 tons of dry matter.
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This calculator is for educational purposes. Double-check important results before acting on them.