Silage Calculator
Estimate how much silage sits in a bunker or drive-over pile from four measurements. Enter the length, width and height in feet plus the as-fed density in pounds per cubic foot, and the tool returns the volume, the total weight in pounds and the tonnage. It treats the stack as a simple box, so a tapered pile will hold a little less than the number shown.
How to estimate silage tonnage
- Enter the bunker or pile length in feet in the Length field.
- Enter the width across the face in feet in the Width field.
- Enter the average silage height in feet in the Height field.
- Leave the Density at 44 lb per cubic foot, or type your own packed density.
- Read the Volume, Weight and Tons cards below the inputs.
- Click Copy estimate to grab the volume and tonnage as text.
Examples
Standard bunker at 40 by 20 by 8 ft
Length 40 ft, Width 20 ft, Height 8 ft, Density 44 lb/cu ft
6400 cu ft, 281600 lb, 140.8 tons
Larger bunker at 50 by 24 by 10 ft
Length 50 ft, Width 24 ft, Height 10 ft, Density 44 lb/cu ft
12000 cu ft, 528000 lb, 264 tons
Loose drive-over pile at 30 by 15 by 7 ft
Length 30 ft, Width 15 ft, Height 7 ft, Density 40 lb/cu ft
3150 cu ft, 126000 lb, 63 tons
Frequently asked questions
What density should I enter for silage?
As-fed corn silage typically runs about 40 to 50 pounds per cubic foot, and 44 is a common planning default that the tool pre-fills. A tightly packed bunker sits at the higher end, while a shallow or loosely packed pile falls lower, so match the figure to how well your stack is packed.
How is the tonnage calculated?
Volume is length times width times height in cubic feet. That volume is multiplied by the density in pounds per cubic foot to get total pounds, and the pounds are divided by 2000 to give US short tons. For 40 by 20 by 8 feet at 44 lb per cubic foot that is 6400 cu ft, 281600 lb, and 140.8 tons.
Is the result as-fed or dry matter tonnage?
It is as-fed tonnage at whatever density you enter, because the density describes the wet, packed feed. To convert to a dry matter basis, multiply the tons by your dry matter fraction, for example 0.35 for silage testing at 35 percent dry matter.
Why does a real pile hold a little less than this?
The math assumes a perfect rectangular box, but drive-over and bunker piles slope down at the sides and taper at the ends. Those angled faces remove volume the box formula still counts, so the true tonnage usually reads a bit below the estimate.
Which ton does the calculator use?
It uses the US short ton of 2000 pounds. If you plan in metric tonnes of 1000 kilograms, take the total pounds figure and convert it separately, since one metric tonne is about 2205 pounds.
Can I use it for a horizontal bag or upright silo?
It is built for rectangular bunkers and flat piles. A silage bag or a round tower silo is cylindrical, so the length by width by height box does not fit and the tonnage would be off. Use a shape-specific calculation for those.
What height should I measure?
Use the average packed height of the silage, not the tallest crown. Because the sides and ends slope, a single peak height overstates the stack, so an average across the face gives a closer estimate.
Is this a guaranteed feed inventory?
No. It is a planning estimate that swings with packing density and pile shape. For a precise inventory, weigh loads across a scale or probe the pile for density, then compare against this figure.
Does my data stay private?
Yes. Every calculation runs locally in your browser as you type, and nothing is sent to a server, so your bunker measurements never leave your device.
Learn more
- Silage density and packing explained
Why packed density drives silage tonnage, what moves the 40 to 50 lb per cubic foot range, and how to pick a number.
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