How this calculator works
This yield-component estimate scales counted ears and kernels from sample area to a whole field, then divides by an assumed kernels-per-bushel value. Iowa State describes a 65000 to 110000 range and a common 90000 assumption. Kernel filling, moisture and sampling error can dominate the estimate. Revenue is before drying, handling, land and production costs; it is not profit.
Formula
Bushels/acre = ears × kernels per ear × 4046.8564224/(sample m2 × kernels per bushel). Total bushels = yield × field acres. Commercial shelled-corn mass = bushels × 56 lb.
Worked example
Thirty ears with 600 kernels each in 1/1000 acre give 18000000 kernels/acre. At 90000 kernels/bushel this is 200 bushels/acre. One acre at $5/bushel gives $1000 gross revenue.
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Frequently asked questions
How many samples should I take?
Use representative locations and multiple ears. Iowa State recommends at least five field locations and at least ten ears for each estimate.
Does 56 lb mean actual test weight?
It is the commercial mass convention for shelled corn. Actual test weight and storage density are different measurements.
Can this predict final yield before grain filling?
Only approximately. Weather and stress during grain filling can change kernel weight enough to materially change the estimate.