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