Crop Yield Calculator Widget
Agronomists, seed companies and farm publications can offer the Purdue yield-component estimate for corn: count ears, count kernel rows and kernels per row, pick a kernel-size factor and get bushels per acre or tonnes per hectare with a realistic range. A second mode multiplies any crop's yield by area and price.
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How it works
Purdue agronomist Bob Nielsen's yield-component method estimates grain yield weeks before harvest. Harvestable ears are counted in a length of row equal to 1/1,000 of an acre (so 30 ears means 30,000 per acre), and several ears are sampled for kernel rows and kernels per row. Yield in bushels per acre is ears per acre times kernels per ear, divided by the number of kernels in a 56-lb bushel. That last 'fudge factor' is unknown until grain fill ends: the method once used 90,000, but Nielsen now suggests 65,000, 75,000 and 85,000 for typical years and 90,000-100,000 after a stressful finish. The widget shows the chosen factor as the headline and the 65,000-85,000 range beside it - his example of 30 ears and 511 kernels gives 236, 204 and 180 bu/acre. Metric results use 1 bu/acre = 62.77 kg/ha. The generic mode simply multiplies yield per hectare or acre by area and an optional price.
Calculation method
- Kernels per ear = kernel rows x kernels per row
- Yield (bu/acre) = ears per acre x kernels per ear / kernels per 56-lb bushel (65,000, 75,000, 85,000, 90,000 or 100,000)
- t/ha = bu/acre x 25.4 kg / 0.4047 ha / 1,000 (1 bu/acre = 62.77 kg/ha); ears per ha x 0.4047 = ears per acre
- Generic: production = yield per area x area; revenue = production x price
Worked examples
Corn yield check
Inputs: 30,000 ears/acre; 16 rows x 32 kernels; 75,000 kernels/bu; 100 acres at $4/bu
Result: 205 bu/acre (12.85 t/ha); range 181-236 bu/acre; 20,480 bu; gross value $81,920
30,000 x 512 / 75,000 = 204.8 bu/acre.
Generic wheat budget
Inputs: 3.5 t/ha; 20 ha; price 180 per t
Result: 70 t; gross revenue 12,600; 630 per hectare
3.5 x 20 = 70; x 180 = 12,600.
Limitations
- The corn method cannot know final kernel weight; results can differ substantially from the combine's yield monitor.
- Generic mode gives gross revenue only - no costs, moisture discounts or storage losses.
- Corn bushels are 56-lb bushels at 15% moisture; other crops have different bushel weights.
Where publishers use it
- A seed-corn company's agronomy blog during August yield-check season
- A crop-insurance agent's page on documenting expected yield
- A farm-radio or ag-news site running a yield-estimate contest
- An FFA or 4-H lesson on sampling a cornfield
- A grain marketing advisor's page linking expected production to forward sales
Questions
How do I count ears for this method?
Measure a length of row equal to 1/1,000 acre - for 30-inch rows that is 17 ft 5 in - count the harvestable ears and multiply by 1,000. Repeat in several places that represent the field.
Which kernels-per-bushel factor should I pick?
Nielsen suggests calculating with 65,000, 75,000 and 85,000 kernels per bushel in a normal year, and 90,000-100,000 if grain fill was stressed by drought or early frost, because small kernels mean more kernels per bushel and less yield. The widget's range card shows 65k to 85k.
How accurate is a pre-harvest estimate?
It is a planning figure. Kernel weight is set during grain fill and can swing the result by tens of bushels; sampling only a few spots can miss variation across the field. Use the range, not the headline, for marketing decisions.
Why is a whole row of the ear not counted?
Count only kernels that are filled. Kernel rows are almost always an even number (commonly 14-18), and kernels per row are counted along one row from the butt to where filled kernels stop.
How do I convert bushels per acre to tonnes per hectare?
For corn at 56 lb per bushel, multiply bu/acre by 0.0628: 200 bu/acre is about 12.55 t/ha. The widget does this automatically when metric units are chosen.
Can I use the generic mode for any crop?
Yes. Enter the expected yield per hectare or acre in any unit (tonnes, bushels, kilograms, crates), the area and the price per unit, and it returns total production and gross revenue before costs.
Sources
- Estimating Corn Grain Yield Prior to Harvest (R.L. Nielsen) - Purdue University Agronomy Department . Ears per 1/1000 acre x kernels per ear / kernel factor; suggests factors 65, 75 and 85 (thousand kernels per 56-lb bushel), 90-100 after stressful grain fill; example 30 ears x 511 kernels = 236, 204, 180 bu/acre. Checked 2026-10-01.
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A2Z Tools Crop Yield Calculator https://a2z.tools/embed/crop-yield-calculator
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[A2Z Tools Crop Yield Calculator](https://a2z.tools/embed/crop-yield-calculator)
Crop Yield Calculator by A2Z Tools - https://a2z.tools/embed/crop-yield-calculator
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