Calculate tons of silage needed (as-fed) by converting dry-matter requirements based on silage moisture content. Free silage planning tool for farms.
The Silage Quantity Calculator determines how many tons of silage (on an as-fed basis) you need to meet your herd’s dry-matter requirements. Because silage typically contains only 30-40% dry matter (60-70% moisture), the as-fed tonnage is significantly higher than the dry-matter requirement — a fact that can surprise producers who are used to thinking in hay tons.
Accurate silage inventory planning prevents the costly problem of running short before the next harvest. Buying silage on the open market is expensive due to high trucking costs relative to value. Building too large a silage pile wastes money and risks spoilage if the pile’s face isn’t consumed fast enough.
This calculator converts your herd’s total dry-matter need for the feeding period into as-fed silage tons, accounting for the silage’s moisture content. It works for corn silage, grass silage, haylage, or any ensiled forage. Enter DM requirements and silage DM percentage to get your purchase or production target.
Silage moisture makes quantity planning tricky — a ton of silage contains far less dry matter than a ton of hay. This calculator prevents over- or under-estimating silage needs by properly accounting for moisture content, ensuring accurate production targets and inventory management. Having a precise figure at your fingertips empowers better planning and more confident decisions.
DM requirement (tons) = Head × DMI from silage (lbs/day) × Feeding days / 2,000 As-fed tons = DM requirement / (Silage DM% / 100) / (1 − Shrink%) Where: DMI from silage = Portion of daily dry-matter intake supplied by silage Silage DM% = Dry-matter percentage of the silage (typically 30-40%) Shrink% = Storage and feedout losses
Result: 2,057 tons as-fed
DM needed = 200 × 18 × 180 / 2,000 = 324 tons DM. As-fed = 324 / 0.35 = 925.7 tons. With 10% shrink: 925.7 / 0.90 = 1,028.6 tons. Wait—let me recalculate: 324 / 0.35 / 0.90 = 1,028.6. For 200 head at 18 lbs DM/day for 180 days, you need approximately 1,029 as-fed tons of 35% DM silage.
A ton of 35% DM corn silage contains only 700 lbs of actual dry matter. A ton of 88% DM hay contains 1,760 lbs. You need 2.5 times more silage tonnage to deliver the same dry matter as hay. This moisture difference is the most common source of silage inventory miscalculation.
To match your feeding needs, work backward from this calculator’s result to determine harvest acreage. Divide as-fed tons needed by expected yield per acre (typically 15-25 tons/ac for corn silage). Add 10% for field losses to get your target harvest acres.
Test silage within 30-60 days of harvest and again mid-feed season. Moisture, pH, and nutrient content can change over time, especially in the top and edges of bunkers. Adjust rations based on current test results rather than harvest-time values.
Well-made corn silage is typically 30-38% dry matter (62-70% moisture). The target harvest moisture for corn silage in bunker silos is 65-70% (30-35% DM), and for upright silos 60-65% (35-40% DM).
Well-managed bunkers with good packing and covering typically lose 8-12% of as-fed tonnage. Uncovered piles or poorly packed bunkers can lose 15-30%. Bag silos typically have the lowest losses at 3-8%.
Measure the dimensions of your bunker in feet (length × width × average depth). Multiply by the pack density (typically 40-50 lbs/cu ft for corn silage). Divide by 2,000 to convert to tons. Compare against your calculated need.
Yes. Many rations combine silage and hay. Calculate the DM contribution from each and adjust the silage quantity accordingly. For example, if half of DMI comes from silage and half from hay, halve the silage DMI input.
Wetter silage means you need more tons as-fed to supply the same DM. Drier silage means fewer tons. Always test silage DM% at feedout and adjust delivery amounts to maintain the correct DM intake.
Corn silage is typically higher in energy (TDN 65-72%) but lower in crude protein (7-9%) compared to good legume hay. Silage also maintains more consistent quality once ensiled, while hay quality degrades over storage time.