Corn Yield per Acre: Formula and Worked Example

To calculate corn yield per acre, divide the harvested corn by the number of acres harvested, converting the grain to bushels and the land area to acres if needed. Enter harvested bushels and acres to get an average yield in bushels per acre (bu/ac); this calculator uses a realistic example of 200 bushels from 2 acres.

Formula

Yield in bushels per acre = harvested bushels ÷ harvested acres.

• Harvested bushels is the quantity of grain, expressed in standard bushels.
• Harvested area is the area from which that grain came, in acres.
• Yield is an average rate, expressed here as bushels per acre (bu/ac).

The optional metric output converts the same yield to metric tonnes per hectare: bu/ac × 0.06277. This is based on a standard 56-pound bushel of shelled corn and standard acre and hectare conversions. The factor is rounded, so the metric result is an approximation.

Worked Example

Using the calculator’s default values:

1. Harvested corn: 200 bu.
2. Harvested area: 2 ac.
3. Divide: 200 ÷ 2 = 100 bu/ac.
4. Convert to metric: 100 × 0.06277 = 6.277 t/ha, which rounds to 6.28 t/ha.

The result is an average across the two acres. It does not mean every part of the field produced exactly 100 bushels per acre.

What Counts as a Bushel?

A bushel is a measure of volume, but grain yield is commonly reported using a standard weight per bushel. For shelled corn, the conventional standard is 56 pounds per bushel, or about 25.4 kilograms. A truckload’s measured weight can therefore be converted to standard bushels by dividing its grain weight by 56 pounds per bushel, provided the weight is expressed on a compatible basis.

Moisture matters because freshly harvested corn contains water. Yield comparisons and official grain measurements commonly use a stated moisture basis; a common standard for corn is 15.5% moisture. If grain is weighed at a higher moisture content, its weight includes more water and should not be compared directly with dry-basis bushels without adjustment. Use the same moisture convention for all quantities being compared, and follow the measurement method specified by the relevant farm, elevator, or reporting system.

How to Calculate Yield from Field Data

For a whole-field estimate, use the total grain from that field and the field’s harvested area. Keep the numerator and denominator matched: do not divide a field’s harvest by the farm’s total acres if some of those acres were not part of that harvest.

• Record the harvested grain. Use a measured grain weight or a reliable total in standard bushels. If beginning with pounds of shelled corn, divide by 56 to estimate standard bushels, after accounting for moisture as appropriate.
• Measure the harvested area. Use acres actually harvested, not planted acres, if headlands, waterways, or unharvested sections were excluded.
• Divide grain by area. The result is the field’s average yield in bu/ac.
• Keep units consistent. Convert kilograms to tonnes or hectares to acres before using a formula that expects bushels and acres.

For example, 18,000 pounds of shelled corn is 18,000 ÷ 56 = about 321.43 standard bushels before any moisture-basis adjustment. If it came from 3 acres, the unadjusted estimate is about 107.14 bu/ac. Report the assumptions with the result if moisture or the bushel convention could affect interpretation.

Area, Sampling, and Yield Maps

One acre is 43,560 square feet, while one hectare is 10,000 square metres and equals about 2.471 acres. If a harvest is measured in metric tonnes and area in hectares, divide tonnes by hectares to get t/ha. For comparison with the calculator’s main output, 1 t/ha is about 15.93 bu/ac for standard shelled corn.

A yield monitor can show changes across a field, but its readings depend on calibration and correct settings, including crop, grain moisture, and header width. A few ears or a small test plot can help assess a specific area, yet they may not represent the entire field. For a defensible whole-field average, total harvested grain and accurately measured harvested area are generally more useful than extrapolating from one unusually good or poor patch.

Interpreting Results and Common Errors

Yield is an average, not a measure of profit, crop quality, or how much grain will be available after storage losses. It also does not identify why a field performed as it did. Weather, soil, planting date, stand density, pests, and harvest conditions can all affect production, but yield alone cannot distinguish among them.

• Mixing units: Dividing pounds by acres gives pounds per acre, not bushels per acre. Convert pounds to bushels using the standard weight first.
• Using planted rather than harvested acres: This changes the average when part of a field was not harvested. State which area the calculation represents.
• Ignoring moisture: Wet grain weighs more for the same amount of dry matter. Check that moisture basis is consistent before comparing yields.
• Rounding too early: Keep measured totals through the division, then round the final result to a sensible precision. Extra decimal places do not make an estimate more accurate.
• Comparing different methods: A scale ticket, yield monitor, and plot estimate can differ because of calibration, area measurement, sampling, or moisture adjustments.

Frequently Asked Questions

How do I calculate corn yield per acre?
Divide the harvested corn in standard bushels by the acres harvested. For example, 600 bushels from 5 acres equals 120 bu/ac.

How many pounds of corn are in a bushel?
A standard bushel of shelled corn is 56 pounds, about 25.4 kilograms. Make sure the grain weight and moisture basis are appropriate before using that conversion.

How do I convert bushels per acre to tonnes per hectare?
For standard shelled corn, multiply bu/ac by approximately 0.06277 to get t/ha. For example, 150 bu/ac is about 9.42 t/ha.

Should I use planted acres or harvested acres?
Use harvested acres when calculating the yield of the land that produced the recorded harvest. If you intentionally want a farm-wide average over planted area, use that area instead and label the result clearly.

Does wet corn produce a higher yield?
It can weigh more because it contains more water, but that does not necessarily mean it contains more dry grain. Compare yields using consistent moisture adjustments and a stated standard.

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in bushels | Harvested corn | bu | 200 | 0
in acres | Harvested area | ac | 2 | 0
out yield | Corn yield per acre | bu/ac | bushels / acres | 2
out metric | Corn yield per hectare | t/ha | bushels / acres * 0.06277 | 2