Corn Bushels Per Acre Calculator
Calculate corn bushels per acre from field measurements using the USDA ear count method. Free, fast, and accurate.
Calculator Inputs
Enter your field measurements
Harvestable ear count
Kernel rows around
Length-wise count
Standard: 15.5%
Take multiple samples from different field locations and average them for the most accurate results. Avoid border rows and unusual spots.
All calculations use USDA-standard formulas. No registration required, works on mobile, tablet, and desktop.
What Is the Corn Bushels Per Acre Calculator?
A corn bushels per acre calculator helps you estimate corn yield in bushels per acre — the standard US yield unit. Bushels per acre (bu/ac) is how every farmer, agronomist, and grain buyer measures and compares corn yield. One bushel equals 56 pounds of corn at 15.5% moisture. The USDA national average is approximately 177 bushels per acre. This calculator uses the ear count method: count ears per acre, sample kernel rows and kernels per row, adjust for moisture, and you get a reliable bushels-per-acre estimate weeks before harvest.
Formula & Method
Formula: Bushels per acre = (Ears × Kernel rows × Kernels per row) ÷ 90,000 × Moisture factor. The constant 90,000 represents the average kernels per bushel at 15.5% moisture. Adjust this number for unusual kernel sizes — 80,000 for large kernels, 100,000 for small kernels — for more accurate results in extreme conditions.
How to Use This Calculator
Using this calculator is simple. Just enter your field measurements in the form above:
- Ears per acre — count harvestable ears in 1/1000 acre of row (17'5" for 30" rows) and multiply by 1,000.
- Kernel rows per ear — average across 5 representative ears. Almost always an even number (14, 16, 18).
- Kernels per row — average across the same 5 ears, counting from base to tip.
- Grain moisture — use a moisture tester. If unknown, enter 15.5% (the standard).
Click "Calculate" and you'll see your estimated yield in bushels per acre, instantly adjusted for moisture. Take multiple samples from different field areas and average the results for best accuracy.
Tips for Accurate Yield Estimation
Right Timing
Estimate at R5-R6 stage for most accurate results. Kernel weight has stabilized.
Multiple Samples
Take 5-10 samples per field from different areas. Average for accuracy.
Representative Ears
Pick average ears — not the biggest or smallest. Avoid border rows.
Accurate Moisture
Test moisture with calibrated meter. Errors here propagate through calculation.
Frequently Asked Questions
Everything you need to know about corn yield calculation
This calculator is accurate within ±10% of actual harvest yield when used correctly. For best results, take 5-10 samples from different field areas, use representative ears (not the biggest or smallest), and apply the correct moisture adjustment. The closer to harvest you estimate, the more accurate the prediction.
Yes, completely free. No sign-up, no download, no cost. Use it as often as you need on any device — desktop, tablet, or smartphone. Works in the field even with limited internet connection.
The best time to estimate corn yield is at the R5 (dent stage) or R6 (physiological maturity) growth stage. At this point, kernel weight has stabilized and moisture levels are predictable. Estimating earlier (during R3-R4) is less accurate because kernels can still abort under stress.
Yes, this calculator is fully mobile-responsive. It works on any smartphone, tablet, or desktop. The interface adapts to your screen size for easy use in the field. Add it to your home screen for quick access during scouting.
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