{
  "id": "corn-yield",
  "version": "eb2b15dd0f65",
  "status": "published",
  "name": "Corn Yield Calculator",
  "question": "What will my corn yield be?",
  "summary": "Estimates corn grain yield in bushels per acre before harvest by the yield component method: ears in a length of row, kernel rows and kernels per row, and a kernel weight factor, with tonnes per hectare.",
  "category": "biology",
  "url": "https://www.acalculator.org/biology/corn-yield-calculator",
  "markdown": "https://www.acalculator.org/biology/corn-yield-calculator.md",
  "kind": "function",
  "method": "Bushels per acre = ears per acre × (kernel rows × kernels per row) ÷ (kernel weight factor × 1,000); ears per acre = ears counted × 43,560 ft² ÷ (row length × row width).",
  "assumptions": [
    "The kernel weight factor stands for kernel size: 65 for heavy kernels, 85 for light ones, 90 to 100 after a stressful grain fill.",
    "Purdue says the method is probably only accurate within about 20 bushels per acre; count several spots in the field.",
    "Tonnes per hectare use the 56 lb bushel of shelled corn."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "w": {
        "title": "Row width",
        "description": "The distance between the centres of two rows.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.05,
        "maximum": 5
      },
      "len": {
        "title": "Length of row counted",
        "description": "The length of row in which you counted the ears. Leave empty to use 1/1000 acre (17.4 ft at 30-inch rows).",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.1,
        "maximum": 10000
      },
      "ears": {
        "title": "Harvestable ears in that length",
        "description": "The number of ears that will be harvested, in the length counted; an average of several rows works.",
        "type": "number",
        "exclusiveMinimum": 0,
        "maximum": 100000
      },
      "rows": {
        "title": "Kernel rows per ear",
        "description": "The average number of kernel rows around each ear (usually an even number from 12 to 20).",
        "type": "number",
        "exclusiveMinimum": 0,
        "maximum": 40
      },
      "k": {
        "title": "Kernels per row",
        "description": "The average number of kernels along each row, not counting the small kernels at the tip.",
        "type": "number",
        "exclusiveMinimum": 0,
        "maximum": 100
      },
      "f": {
        "title": "Kernel weight factor",
        "description": "Thousands of kernels per bushel: 65, 75 or 85 for normal grain fill, 90 to 100 after a stressful season.",
        "type": "number",
        "minimum": 50,
        "maximum": 120
      }
    }
  },
  "outputs": {
    "yield": {
      "label": "Estimated yield",
      "description": "Ears per acre × kernels per ear ÷ (kernel weight factor × 1,000), in bushels per acre.",
      "format": "number"
    },
    "tonnes": {
      "label": "Estimated yield (metric)",
      "description": "The yield in tonnes per hectare, at 56 lb of shelled corn per bushel.",
      "format": "number"
    },
    "earsPerAcre": {
      "label": "Ears per acre",
      "description": "The ears counted ÷ the area of row counted (length × row width), per acre.",
      "format": "number"
    },
    "kernelsPerEar": {
      "label": "Kernels per ear",
      "description": "Kernel rows per ear × kernels per row.",
      "format": "number"
    },
    "rowLength": {
      "label": "Row length for 1/1000 acre",
      "description": "The length of row at this row width that covers 1/1000 acre.",
      "format": "quantity",
      "unit": "ft"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "w": "30 in",
      "ears": 30,
      "rows": 16,
      "k": 32,
      "f": 85
    },
    "outputs": {
      "yield": 180.7058823529412,
      "tonnes": 11.342486241320275,
      "earsPerAcre": 30000,
      "kernelsPerEar": 512,
      "rowLength": 5.3108352
    },
    "text": "Your corn should yield about 180.7 bushels per acre."
  },
  "examples": [
    {
      "given": {
        "w": 0.762,
        "ears": 30,
        "rows": 16,
        "k": 31.9375,
        "f": 75
      },
      "expect": {
        "yield": 204.4,
        "earsPerAcre": 30000,
        "kernelsPerEar": 511,
        "tonnes": 12.829710674264222
      },
      "source": "Nielsen RL, Estimating Corn Grain Yield Prior to Harvest, Purdue University Corny News Network, August 2021 (bushels per acre = ears per acre × average kernels per ear ÷ a kernel weight factor in thousands; 17.4 ft of 30-inch row is 1/1000 acre; factors of 65, 75 and 85, or 90 to 100 under stress; 30 ears and 511 kernels per ear give 236, 204 and 180 bu/ac), https://www.agry.purdue.edu/ext/corn/news/timeless/yldestmethod.html (retrieved 2026-10-03); Iowa State University Extension, Ag Decision Maker C6-80, Metric Conversions (corn with a 56-pound bushel: 1 bushel per acre = 0.0628 metric tons per hectare), https://www.extension.iastate.edu/AGDm/wholefarm/html/c6-80.html (retrieved 2026-10-03); hand calculation in content.mdx: 30 × 511 ÷ 75 = 204.4 bu/ac"
    },
    {
      "given": {
        "w": 0.762,
        "ears": 30,
        "rows": 16,
        "k": 31.9375,
        "f": 85
      },
      "expect": {
        "yield": 180.35294117647058,
        "rowLength": 5.3108352000000005
      },
      "source": "Nielsen RL, Estimating Corn Grain Yield Prior to Harvest, Purdue University Corny News Network, August 2021 (bushels per acre = ears per acre × average kernels per ear ÷ a kernel weight factor in thousands; 17.4 ft of 30-inch row is 1/1000 acre; factors of 65, 75 and 85, or 90 to 100 under stress; 30 ears and 511 kernels per ear give 236, 204 and 180 bu/ac), https://www.agry.purdue.edu/ext/corn/news/timeless/yldestmethod.html (retrieved 2026-10-03); hand calculation in content.mdx: 30 × 511 ÷ 85 = 180.4 bu/ac; 43,560 ÷ 2.5 ÷ 1,000 = 17.424 ft"
    },
    {
      "given": {
        "w": 0.9144,
        "len": 6.096,
        "ears": 25,
        "rows": 16,
        "k": 30,
        "f": 85
      },
      "expect": {
        "earsPerAcre": 18150,
        "yield": 102.49411764705883,
        "tonnes": 6.433316414998843
      },
      "source": "Nielsen RL, Estimating Corn Grain Yield Prior to Harvest, Purdue University Corny News Network, August 2021 (bushels per acre = ears per acre × average kernels per ear ÷ a kernel weight factor in thousands; 17.4 ft of 30-inch row is 1/1000 acre; factors of 65, 75 and 85, or 90 to 100 under stress; 30 ears and 511 kernels per ear give 236, 204 and 180 bu/ac), https://www.agry.purdue.edu/ext/corn/news/timeless/yldestmethod.html (retrieved 2026-10-03); Iowa State University Extension, Ag Decision Maker C6-80, Metric Conversions (corn with a 56-pound bushel: 1 bushel per acre = 0.0628 metric tons per hectare), https://www.extension.iastate.edu/AGDm/wholefarm/html/c6-80.html (retrieved 2026-10-03); hand calculation in content.mdx: 25 × 43,560 ÷ (20 × 3) = 18,150 ears per acre"
    }
  ],
  "sources": [
    "Nielsen RL, Estimating Corn Grain Yield Prior to Harvest, Purdue University Corny News Network, August 2021 (the yield component method; 17.4 ft of 30-inch row is 1/1000 acre; fudge factors 65, 75 and 85, or 90 to 100 under stress; 30 ears and 511 kernels per ear give 236, 204 and 180 bu/ac; accurate within about 20 bu/ac). https://www.agry.purdue.edu/ext/corn/news/timeless/yldestmethod.html (retrieved 2026-10-03)",
    "Iowa State University Extension, Ag Decision Maker C6-80, Metric Conversions (corn with a 56-pound bushel: 1 bushel per acre = 0.0628 metric tons per hectare). https://www.extension.iastate.edu/AGDm/wholefarm/html/c6-80.html (retrieved 2026-10-03)"
  ],
  "related": [
    "acreage",
    "acres-per-hour",
    "fertilizer"
  ],
  "changelog": []
}