Agricultural Field Calculators
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Grain Drydown Calculator

Calculate moisture shrink, dry sellable weight, artificial drying costs, and net revenue for corn, wheat, soybeans, canola, and dry beans. Supports propane, flat-rate, and per-point drying methods plus trucking cost estimation.

Calculate moisture shrink, dry bushel equivalent, drying cost per point, and net revenue at any harvest moisture level. Enter your wet bushels, harvest moisture, target moisture, and drying cost — get shrink percentage, dry bushels, total drying cost, and net value after drying. Used by farmers for harvest timing decisions, elevator shrink calculations, and ethanol grain receiving. Covers corn, soybeans, wheat, and canola.

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Grain Drydown Calculator

Calculate shrink, sellable weight, drying costs, and trucking costs.

Moisture & Weight
Artificial Drying Costs (optional)
Trucking Costs (optional)

Fill in the fields and press Calculate to see your results.

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Disclaimer — Drydown costs and shrink calculations are estimates. Actual shrink factors vary by grain variety, dryer type, and operating conditions. Verify drying costs with your elevator or dryer operator before making marketing decisions.

Understanding Grain Drydown and Moisture Shrink

When you harvest corn at 20% moisture and sell at the standard 15%, you lose bushels — not just water. That's moisture shrink: the reduction in grain weight and volume as water is removed. The standard shrink formula is: dry bushels = wet bushels × (1 − harvest moisture%) ÷ (1 − target moisture%).

This calculator handles both natural field drydown and artificial propane or natural gas drying. Enter your harvest moisture, target moisture, drying cost per point, and trucking costs to get net revenue per bushel and per acre. The results help you decide whether to dry artificially, sell wet with a moisture discount, or wait for field drydown.

For storage after drying, see the Grain Bin Capacity Calculator.

Frequently Asked Questions

Grain drydown is the process by which harvested grain loses moisture over time — either naturally in the field or artificially in a grain dryer. Grain is sold at a standard moisture content (15.5% for corn, 13.5% for soybeans, 13.5% for wheat). Grain harvested above that moisture is "shrunk" — meaning you receive fewer bushels than you harvested, because water weight is deducted. Drydown calculators help farmers decide whether to harvest early and pay drying costs, or wait for the crop to dry naturally in the field.

Dry weight = Wet weight × (1 − harvest MC%) ÷ (1 − target MC%). Example: 50,000 bu at 20% to 15.0%: 50,000 × 0.80 ÷ 0.85 = 47,059 dry bu. That is 2,941 bu of shrink, about 5.9%.
15.0%. Corn above 15% receives drying and shrink charges. Most elevators apply 1.3–1.4% weight reduction per point of moisture removed, plus a separate drying charge of $0.03–0.06/bu/point.
Soft white wheat, hard red winter, and spring wheat all standardize at 13.5%. Some elevators accept up to 14.0% with no discount. Grain above 14.5% typically requires drying before acceptance.
Commercial drying costs $0.03–0.06 per bushel per point depending on propane prices and dryer type. At $1.00/gallon propane, plan approximately $0.035–0.04/bu/point for continuous-flow dryers.
Corn typically dries 0.5–0.75 percentage points per day under good fall conditions. Drydown slows significantly below 55°F. From black layer formation (~30–35% moisture) to 15% typically takes 25–40 days.
Yes — after calculating, click Export PDF and enter your farm name for the header. The PDF shows all inputs, moisture shrink, drying cost breakdown, trucking cost, and net revenue per bushel and per acre.

Wet weight ÷ dry weight = (100 − harvest moisture) ÷ (100 − target moisture). Example: drying 10,000 bu from 25% to 15% moisture — dry weight = 10,000 × (100−25) ÷ (100−15) = 10,000 × 75 ÷ 85 = 8,824 bu. You lose 1,176 bu (11.8%) to shrink from moisture removal. Once dried, use the Grain Bin Capacity Calculator to verify your storage can handle the load.

Commercial dryers typically charge $0.04–$0.07 per bushel per point (percentage point) of moisture removed. Drying corn from 25% to 15% (10 points) at $0.05/point costs $0.50/bu. On-farm propane drying usually runs $0.025–$0.045/point depending on propane price and dryer efficiency. Enter this drying cost in the Crop Break-Even Calculator to see how it affects your minimum profitable price.