Corn Yield Calculator
Enter ears per acre and kernel counts per ear, plus a kernels-per-bushel factor, to estimate corn yield. This is a pre-harvest field estimate, not a substitute for actual harvested yield.
Last updated: September 25, 2026
Frequently asked questions
How accurate is this yield estimate compared to actual harvest?
It's a useful early projection, not a guarantee - actual harvested yield depends on factors this method can't fully capture, including final kernel fill and weight, grain moisture at harvest, in-field variability between sampled and unsampled areas, and mechanical harvest losses. Treat the result as a planning estimate that should be updated as the season progresses.
What is the kernels-per-bushel factor and why does it matter so much?
It represents the average number of kernels it takes to fill one bushel, which varies with kernel size and test weight - smaller or lighter kernels mean more kernels per bushel (a higher factor, lower yield estimate for the same ear count), while larger, well-filled kernels mean fewer kernels per bushel. Because this factor is uncertain until harvest, many practitioners run the calculation with a range of factors (e.g., 80,000 and 95,000) to bracket a plausible yield range rather than relying on a single number.
How do I count ears per acre in the field?
A common approach is to measure a row length that represents a known fraction of an acre based on your row spacing, count the ears in that length, then scale up to a full acre - repeating this in several representative locations in the field improves accuracy over a single sample.
Should I count kernel rows and kernels per row on every ear, or just a sample?
Sampling several representative ears (not just one) and averaging their kernel row count and kernels per row gives a more reliable estimate than measuring a single ear, since kernel counts vary noticeably even within the same field.
Why does this calculator show a metric tonnes/hectare figure too?
Bushels per acre is the standard US unit for corn yield, while tonnes per hectare is standard in most other countries - showing both avoids a separate conversion step regardless of which unit you're working in. The conversion used (1 bu/ac ≈ 0.0628 tonnes/ha) reflects corn's standard test weight and moisture reference.
Does this account for harvest losses from the combine?
No - this estimates the grain present in the field based on ear and kernel counts, before harvest. Mechanical harvest losses (shelling, header loss, etc.) reduce what's actually collected, so realized yield at the scale is typically somewhat lower than this pre-harvest field estimate.