Corn and Grain Yield Calculator

Counting Your Way to a Bushel Estimate

• Choose the crop, because a bushel holds a very different seed count each.
• Enter the ground area you actually harvested, in square feet.
• Count plants or ears rather than guessing a stand you did not measure.
• Enter seeds per plant: kernels per ear times ears per stalk for corn.
• Weigh and count a few ears and average them before filling that line.
• Set harvest loss for shelling, birds, lodging and dropped ears.
• Read the bushel line first, then the weight in pounds or kilograms.
• Check plant density against extension recommendations for your crop.
• Compare the per-acre yield line with a realistic local benchmark.
• Recount one short row next season instead of trusting a remembered figure.

Seeds Divided by the Standard Bushel Count

Worked Example: 48 Corn Plants on 400 Square Feet

• Leave the crop selector on corn, at 80,000 kernels per bushel.
• Enter 400 sq ft of patch and the 48 stalks you stood there.
• Count one average ear at 550 kernels and enter that rate.
• Forty-eight plants times 550 kernels gives 26,400 kernels standing.
• Set loss to 10 per cent for birds, tip shrink and dropped ears.
• Subtracting that loss leaves 23,760 harvestable kernels for the bin.
• Divide by 80,000 and the harvest reads 0.30 bushel.
• At 56 lb per bushel that is just over 16 lb of shelled grain.
• Plant density works out at 5,227 stalks for a full acre.
• A field at 30,000 stalks an acre clears 180 bushels, so density explains the gap.

Bushel Weights and Kernel Counts

Key Terms

Bushel

A weight standard for grain, defined per crop rather than by market volume.

Kernel count

Seeds produced per plant, the raw input behind every yield estimate.

Test weight

Pounds per bushel actually harvested, which drops when grain is light or wet.

Lodging

Stalks falling over before harvest, costing yield and seed at the same time.

Harvest loss

Grain left in the field through shelling, birds, weather and machine settings.

Plant density

Stand per unit area, the lever that most often explains a disappointing plot.

Reading a Yield Number Honestly

• A bushel of corn weighs 56 lb whether it came from a combine or a five-gallon bucket, which is why small-plot figures should only be compared with per-acre benchmarks after the area is converted.
• Garden spacing is generous by field standards, so a 400 sq ft patch reading 30 bushels per acre is doing well for its density rather than failing.
• Kernels per ear is the variable worth measuring, because ear count per stalk is usually one while drought and poor pollination shift kernel set early.
• Weight alone misleads when grain is wet, since a bushel at 23 per cent moisture is not the same harvest as one sold at 15 per cent.
• Count a random sample of plants rather than the best row, because the temptation to sample your biggest ears adds a bushel or two to any estimate.

Common Mistakes & Fixes

• Dividing by the wrong crop's kernel count, such as wheat entered as corn.
• Counting ears and kernels on the same input line, which double-counts the stalk.
• Leaving the harvest loss at zero for a plot that birds have found.
• Reporting fresh weight without moisture, then comparing it with a dried elevator figure.
• Sampling only the strongest plants and then calling the result a plot average.
• Forgetting that a bushel is a defined weight, not a market basket.

When to Reach for This

Corn and Grain Yield Calculator: Frequently Asked Questions