Skip to content
UseCalcNow

Part of the Agriculture collection — 4 tools available

Agriculture

Silage Calculator — Bunker & Tower Volume

Calculate silage volume and tonnage for bunker silos, trench silos, and tower silos. Estimate feed supply based on dimensions and silage density.

About This Calculator

Knowing how much silage your bunker or tower holds is critical for feed budgeting through the winter months when fresh forage isn't available. Silage density varies significantly with crop type, moisture content, and packing quality — well-packed corn silage averages 45 pounds per cubic foot, while poorly packed material can be 20% less dense, throwing off your estimates. Running out of silage mid-winter forces expensive emergency feed purchases, while overestimating means wasted storage space. Our silage calculator converts your storage dimensions into total tonnage and dry matter equivalents for accurate feed planning.

The Formula Behind This Calculator

Volume (cu ft) = L * W * Depth Tons = Volume * 40-45 lbs/cu ft 1 ton corn silage ~ 1.5 tons hay.

Understanding the math helps you verify results and make better decisions for your project.

How to Use

  1. 1Measure the length and width of your bunker or trench silo.
  2. 2Estimate the average settled depth of the silage pack.
  3. 3Set the density — 45 lb/cu ft for well-packed corn silage is standard.
  4. 4Review total tons as-fed and dry matter equivalent.

When to Use

  • Planning winter feed supply and determining if storage is adequate.
  • Estimating silage inventory before the feeding season.
  • Comparing bunker capacity vs tower silo capacity for expansion.

Tips

  • Pack silage in thin layers (6 inches) with heavy tractor traffic for maximum density.
  • Cover bunker silos immediately with oxygen-barrier plastic — exposure loses 20%+ on top layers.
  • Corn silage is typically 30-35% dry matter; haylage is 35-45% dry matter.

FAQ

What density should I use for my silage?

Well-packed corn silage: 42-48 lb/cu ft. Haylage: 35-45 lb/cu ft. Poorly packed silage can be as low as 25-30 lb/cu ft, wasting storage space and increasing spoilage.

How do I convert as-fed to dry matter?

Multiply as-fed weight by the dry matter percentage. Corn silage at 35% DM means 1 ton as-fed = 0.35 tons DM. This matters for comparing feeds with different moisture levels.

How long will my silage last?

Divide total tons by daily feeding rate. A 100-cow dairy herd eating 40 lb silage/cow/day uses 2 tons/day. A 500-ton bunker lasts about 250 days.

Related Calculators