What is a typical silage packing density?

Well-packed corn silage in a bunker typically runs 14–16 lbs of fresh weight per cubic foot. Drive-over piles tend to pack less densely, averaging 12–14 lbs/ft³. Higher density means less spoilage and more tons per foot of bunker length. Use 14 lbs/ft³ as a safe starting point if you have not weighed your material.

How is dry matter tonnage calculated?

Dry matter tons = fresh weight tons × (1 − moisture fraction). For example, corn silage at 65% moisture has 35% dry matter, so 100 fresh tons contains 35 dry matter tons. This tool accepts either a preset crop moisture or a custom value you enter.

What is TDN and why does it matter?

Total Digestible Nutrients (TDN) is a measure of the total energy available from a feed. It is expressed as a percentage of dry matter. Corn silage is typically 65–70% TDN, while grass silage runs 55–65%. Multiplying dry matter tons by the TDN percentage gives the TDN tons available for ration balancing.

How does the drive-over pile shape differ from a bunker?

A drive-over (ag-bag or push-up) pile has a rounded or triangular cross-section. This calculator models it as a triangular prism: volume = 0.5 × width × height × length. A bunker or trench silo has vertical walls and a flat floor, so its cross-section is rectangular: volume = width × height × length. Choosing the correct shape gives a more accurate tonnage estimate.

What moisture level should I use for corn silage?

Corn silage harvested at the recommended two-thirds milk-line stage typically runs 62–68% moisture (32–38% dry matter). Wetter silage (above 70%) risks seepage losses; drier silage (below 55%) is harder to pack and may heat. If you have a recent forage test, use that moisture figure for the most accurate result.

Can I use this for haylage or grass silage?

Yes. Select "Grass / Haylage" from the crop preset or enter a custom moisture percentage. Haylage typically ranges from 40–60% moisture. The density may also differ — grass silage often packs at 10–13 lbs/ft³ compared to corn silage. Adjust the density field accordingly.

Silage Calculator

Name: Silage Calculator
Availability: InStock
Author: Nham Vu

Enter the dimensions and density of your silage pile or bunker to instantly estimate weight, dry matter tonnage, and total feed energy.

Silage Pile Inputs

Pile / Silo Type

Rectangular cross-section — vertical walls, flat floor.

Length (ft)

Width (ft)

Height (ft)

Enter interior dimensions. For drive-over piles, height is peak height.

Crop Type

Moisture (%)

Density (lb/ft³)

TDN (% DM)

Values auto-filled from crop preset. Edit to match your forage test results.

Results

Fill in the inputs and click Calculate.

Summary

Enter the dimensions and density of your silage pile or bunker to instantly estimate weight, dry matter tonnage, and total feed energy.

How it works

Select the silage pile type: drive-over pile (triangular cross-section) or bunker/trench silo (rectangular cross-section).
Enter the pile dimensions: length, width, and height (or peak height for a drive-over pile).
Select the crop type or enter a custom moisture percentage to set dry matter content.
Enter the packing density in pounds per cubic foot (typical values are pre-filled).
Click Calculate to see total fresh weight, dry matter tons, and estimated TDN.
Use the breakdown panel to verify each step of the calculation.

Use cases

Estimate how many tons of silage are in an existing pile before feeding season.
Plan bunker capacity when harvesting corn, sorghum, or grass silage.
Compare pile volumes and densities across different fields or crop years.
Calculate dry matter intake requirements and match against herd needs.
Verify silage inventory for lender or insurance reporting.
Budget silage supply for custom feedlot or dairy ration planning.
Determine if additional silage storage is needed before harvest.
Cross-check custom silage probe results against volume-based estimates.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu