Corn Yield Calculator

Estimate corn grain yield in bushels per acre with the Yield Component Method: ears per acre times kernel rows per ear times kernels per row, divided by the kernel-weight factor.

Quick Facts

Method
Yield Component Method: (ears/acre × rows/ear × kernels/row) ÷ 90,000
The 90,000 divisor is the assumed kernels in one 56 lb bushel of shelled corn at 15.5% moisture.

Your Results

Calculated
Estimated yield
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Bushels per acre (bu/acre)
Kernels per ear
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Rows × kernels per row
Total kernels per acre
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Ears × kernels per ear
Metric yield
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Tonnes per hectare

Ready

Enter your field counts and select Calculate.

The Yield Component Method for corn

This calculator uses the Yield Component Method (sometimes called the "corn yield estimator" or "kernel-count method"), the standard in-season yield estimate taught by university extension services such as Iowa State, the University of Illinois, and Purdue. It estimates grain yield from the physical components of the ear:

Yield (bu/acre) = (Ears per acre × Rows per ear × Kernels per row) ÷ 90,000

The numerator is simply the total number of kernels on one acre of field. Dividing by 90,000 converts kernels into bushels, because a 56-pound bushel of shelled corn at 15.5% moisture contains roughly 90,000 kernels on average.

What each input means

  • Ears per acre — the number of harvestable ears on one acre. A common shortcut is to count ears in 1/1000th of an acre (17 ft 5 in of row at 30-inch spacing) and multiply by 1,000. Only count ears that will actually produce grain.
  • Kernel rows per ear — corn ears almost always have an even number of rows, typically 14 to 18. Count the rows around the circumference of a representative ear.
  • Kernels per row — count down the length of the ear, excluding the tip kernels that are aborted or undersized. Fifteen to forty per row is typical.
  • Kernel-weight factor — the assumed number of kernels per bushel, default 90,000. Lower it toward 80,000 when kernels are large and heavy (good year), raise it toward 95,000 when kernels are small and light (drought or stress).

Why the estimate matters

Made a few weeks before harvest (once kernels reach the dough or dent stage), this estimate helps growers plan grain storage and drying capacity, forward-contract a realistic share of the crop, and compare hybrids or management zones. Because it is built from direct ear counts rather than historical averages, it responds to the current season's growing conditions.

Typical reference points

  • A strong Corn Belt field: about 34,000 ears/acre × 16 rows × 38 kernels ÷ 90,000 ≈ 230 bu/acre.
  • An average field: about 30,000 ears/acre × 16 rows × 35 kernels ÷ 90,000 ≈ 187 bu/acre.
  • A drought-stressed field: about 24,000 ears/acre × 14 rows × 25 kernels ÷ 95,000 ≈ 88 bu/acre.

Frequently Asked Questions

What is the corn Yield Component Method formula?
Estimated yield in bushels per acre equals (ears per acre × average kernel rows per ear × average kernels per row) divided by 90,000. The 90,000 is the assumed number of kernels in one 56-pound bushel of shelled corn at 15.5% moisture.
Why is the divisor 90,000, and when should I change it?
90,000 is the standard average kernel-weight factor used by university extension services. Actual kernels per bushel range from about 75,000–80,000 in a favorable year with large, heavy kernels to 95,000 or more when kernels are small and light. Use a lower divisor for good conditions and a higher divisor for a stressed crop; the divisor is the single biggest source of uncertainty in the estimate.
How do I get ears per acre?
Measure off 1/1000th of an acre of row — at 30-inch row spacing that is 17 feet 5 inches — count the harvestable ears in that length, and multiply by 1,000. Repeat in five or more spots across the field and average, since stand and ear count vary within a field.
Should I count the tip kernels?
No. Skip the small, aborted kernels at the very tip of the ear that will not fill. Counting them inflates the kernels-per-row figure and overstates the yield estimate.
How accurate is this estimate?
It is a good pre-harvest planning tool, typically within about 20 bu/acre when sampling is done carefully across a representative set of ears. Accuracy depends most on the number of samples you average and on choosing an appropriate kernel-weight factor for the season.

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