Corn Crop Calculator
Plan the whole crop — not just grain. Estimate bushels, silage tons, and stover from one field walk so you can size harvest equipment and storage in advance.
Corn Yield Calculator
Enter measurements to estimate grain yield (the base for silage and stover too)
Harvestable ear count
Kernel rows around
Length-wise count
Standard: 15.5%
Use "Average of multiple" for accuracy
A quick rule of thumb: silage tons per acre (at 65%% moisture) ≈ grain bu/ac ÷ 7 to 8. A 200 bu/ac grain crop typically yields 25-29 tons of silage. Use this to plan chop windows and bunker space.
Corn stover dry matter ≈ grain dry matter. A 200 bu/ac crop leaves roughly 200 × 56 lb = 11,200 lb of stover dry matter per acre, or about 5.6 dry tons. Harvest about half of that to protect soil.
Why Plan the Whole Crop?
A corn field produces more than grain. The same crop that yields 200 bushels per acre also produces 25 to 29 tons of silage (if you chop it) and 5 to 6 dry tons of stover (if you bale it). For farms that milk cows, run a feedlot, or sell biomass, the grain number alone undersells what the field is worth. This page helps you put a number on all three products of a corn crop so you can make confident decisions about what to harvest and how to store it.
The grain yield estimate above is the foundation. Once you have a bushels-per-acre figure from the USDA ear count method, two well-established ratios let you convert it into silage and stover estimates without a second field walk. The grain-to-silage ratio runs about 7 to 8 bushels of grain per ton of silage at 65%% moisture — a relationship documented in university extension literature and stable across hybrids. The grain-to-stover ratio is roughly 1:1 on a dry-matter basis, meaning a bushel of grain (56 lb dry) corresponds to about 56 lb of stover dry matter.
Converting Grain Yield to Silage Yield
Silage is whole-plant corn chopped at roughly 65%% moisture and packed into a bunker, pile, or bag. Dairy and beef producers value it because it captures the entire plant — grain, cob, leaves, and stalk — in one feed product. The standard conversion: divide grain bu/ac by 7.5 to get silage tons per acre at 65%% moisture. A 200 bu/ac grain crop therefore yields about 27 tons of silage. Adjust down slightly for drought-stressed corn (which has a lower grain-to-forage ratio) and up slightly for leafy, tall hybrids bred for silage.
Timing matters for silage. The ideal chop window is when whole-plant moisture is between 63%% and 68%% — usually 45 to 60 days after silking, or about the R5 (dent) stage. Chop too wet and the silage seeps, losing nutrients; chop too dry and it won't pack, spoiling in storage. The grain yield estimate is most useful here as a planning tool: it tells you whether the crop is worth chopping at all, and helps you line up custom choppers and haulers before the window opens.
Estimating Stover Production
Stover is the residue left after grain harvest — stalk, leaves, cob, and husk. On a dry-matter basis, corn produces roughly one pound of stover for every pound of grain. A 200 bu/ac crop therefore leaves about 11,200 lb (5.6 tons) of stover dry matter per acre. Not all of that should be removed: agronomists generally recommend leaving at least 2 to 3 tons per acre to protect soil from erosion and maintain organic matter. If you bale stover for bedding or biomass, plan to take roughly half of what's produced.
Putting It Together: A Worked Example
Suppose the calculator returns 195 bu/ac for a 160-acre field destined to feed a dairy herd. Grain: 195 × 160 = 31,200 bushels. Silage equivalent: 195 ÷ 7.5 = 26 tons/ac × 160 = 4,160 tons of silage. Stover: 195 × 56 = 10,920 lb/ac dry ≈ 5.5 tons/ac; at 50%% removal that's 2.75 tons/ac × 160 = 440 bales (assuming 1-ton bales). One field walk gives you the numbers to plan grain bin space, bunker volume, and bale storage — all before the crop is mature.
Frequently Asked Questions
Everything you need to know
Divide grain bushels per acre by about 7.5 to estimate silage tons per acre at 65% moisture. A 200 bu/ac grain crop yields roughly 27 tons of silage. The ratio varies from about 7:1 for grain-heavy hybrids to 8:1 for leafy silage hybrids, and runs lower (more silage per bushel) when drought reduces grain fill.
Corn produces roughly one pound of stover dry matter for every pound of grain. A 200 bu/ac crop (200 x 56 = 11,200 lb of grain) leaves about 11,200 lb, or 5.6 dry tons, of stover per acre. Agronomists recommend leaving at least 2-3 tons per acre to protect soil; the rest can be baled for bedding or biomass.
Chop corn silage when whole-plant moisture is between 63% and 68%, which typically falls 45-60 days after silking at the R5 (dent) stage. Chop too wet and the silage seeps and loses nutrients; chop too dry and it won't pack properly, leading to spoilage. Check moisture with a Koster tester or microwave test before committing the whole field.
Yes. The ear count method works for any corn crop because it measures grain production. For silage, take the grain bu/ac result and divide by 7.5 to estimate silage tons per acre. For dedicated silage hybrids with lower grain-to-forage ratios, divide by 8 instead. The calculator handles the grain math; the conversions on this page handle the rest.
Editorial Standards & Sources
All formulas and benchmarks on this page are based on the USDA Yield Component Method (Nielsen, R.L., Purdue University Extension) and USDA NASS crop production data. Our calculators are reviewed annually against the latest extension publications from Iowa State, University of Illinois, University of Nebraska, and Ohio State.
Methodology: The default 90,000-kernels-per-bushel divisor and the 15.5% moisture standard used throughout this site come directly from published USDA and land-grant extension guidance rather than an internal estimate. Where a figure is our own approximation — such as the ±10% accuracy range for the ear count method — we say so explicitly rather than presenting it as an official statistic.
Known limitations: Pre-harvest estimates from any ear-count-based calculator are a planning tool, not a substitute for actual combine yield-monitor data or elevator scale tickets. Accuracy depends heavily on how representative the field samples are; we recommend a minimum of five sample locations per field, as outlined in the sampling guidance on this page.
Content last reviewed for accuracy in August 2025. Have a correction or suggestion? Contact our editorial team — we respond to all substantive feedback within 5 business days.