Estimate how much forage a bunker or pile holds, in as-fed and dry-matter tons.
Enter pile length, width, height, typical silage density (lb/cu ft), and moisture percentage. The calculator uses a trapezoidal cross-section approximation (volume ≈ L×W×H÷2) to estimate volume, as-fed weight, and dry-matter tonnage.
A dairy producer thought their 100×30×12 ft pile held 180 tons. After proper packing it actually held 720 tons. Underestimating by 4× meant short-order planning for 60 milking cows — a daily scramble that better math would have prevented.
✓ Expert Reviewed: This calculator and its content have been reviewed by agricultural experts. Formulas are based on standard extension service recommendations. For site-specific advice, consult your local agronomist.
Enter the required input values in the form fields above. Each field includes default values that you can adjust to match your specific situation. Click the Calculate button (or simply change any input) to see instant results. Use the Metric/Imperial toggle to switch between unit systems. Results are displayed in the results panel and can be used for farm planning and decision-making.
This calculator is designed to help farmers, agronomists, and agricultural students make quick, accurate calculations for farm management. It uses standard agricultural formulas based on extension service recommendations and scientific literature. Whether you are planning inputs, estimating yields, or managing finances, this tool provides reliable estimates to support your decisions.
For a trapezoidal pile, Volume (cu ft) ≈ length × width × height ÷ 2. Weight (lb) = volume × packed density. As-fed tons = weight ÷ 2,000. Dry matter tons = as-fed tons × (100 − moisture %) ÷ 100. Typical packed densities: 35–45 lb/cu ft for corn silage at 65% moisture.
100 ft × 30 ft × 12 ft pile, 40 lb/cu ft, 65% moisture: volume = 18,000 cu ft. Weight = 720,000 lb = 360 as-fed tons. Dry matter = 360 × 0.35 = 126 tons DM.
Common mistakes: using loose (not packed) density; forgetting the ÷2 trapezoid factor; ignoring that pile sloping reduces true volume; confusing as-fed with dry-matter tons. Pack carefully and sample moisture for accuracy.
Well-packed corn silage ranges 35–45 lb/cu ft (as-fed). Good packing with enough tractor weight on the pile reaches 40+; poorly packed piles can be 25–30 lb/cu ft and spoil faster.
A pile has a triangular/trapezoidal cross-section, not a rectangular box. The ÷2 approximates the sloped sides. For a flat-top bunker silo with vertical walls, use full L×W×H instead.
Ideal harvest moisture is 60–65% for bunkers, 65–70% for bags. Too wet causes seepage and clostridial fermentation; too dry causes heating and molding.
Dry matter is what remains after water is removed. At 65% moisture, DM = 35%. Rations are balanced on DM, not as-fed weight, because water content varies.
Thin layers (6 inches), continuous packing with heavy tractors, fill in wedge shape, pack along the edges repeatedly, and seal within hours. Density directly determines spoilage and feed quality.