Harvest Moisture Loss & Shrink Calculator

At harvest, grain almost never comes off the field at the exact moisture it is sold at. Wet grain weighs more because of the extra water, so it must be shrunk to the standard moisture before it can be priced. This calculator converts your wet field weight into standard-moisture bushels, applies the elevator’s moisture discount, and tells you whether drying it yourself pays.

How it works

Two shrink steps and a discount combine into the settlement:

dry_weight   = wet_weight × (100 − field_moisture) / (100 − standard_moisture)
net_weight   = dry_weight × (1 − handling_shrink/100)
bushels      = net_weight / test_weight_per_bushel
discount     = wet_bushels × points_over_standard × discount_per_point
net_payment  = bushels × price − discount

The first line removes the water; the second removes handling shrink; the third converts to bushels; the discount docks dollars for every moisture point above the standard.

Worked example: corn at 18% moisture

Suppose you deliver 100,000 lb of corn reading 18% on the moisture meter. The elevator buys at a 15% standard, applies a 0.5% handling shrink, uses a 56 lb test weight, and docks $0.05 per point per bushel above standard.

Step 1 — Remove the water:

dry_weight = 100,000 × (100 − 18) / (100 − 15)
           = 100,000 × 82 / 85
           ≈ 96,471 lb

Step 2 — Apply handling shrink:

net_weight = 96,471 × (1 − 0.005) = 96,471 × 0.995 ≈ 95,988 lb

Step 3 — Convert to bushels:

bushels = 95,988 / 56 ≈ 1,714 standard-moisture bushels

Compare that to the 100,000 / 56 ≈ 1,786 wet-scale bushels you might have naively counted. The shrink alone erases 72 bushels.

Step 4 — Moisture discount:

You are 3 points above standard (18 − 15), so with $0.05/point/bushel the elevator docks 1,786 × 3 × $0.05 ≈ $268 from the settlement.

Sell-or-dry decision

The break-even drying cost is the total moisture discount divided by the bushels you would net after drying. If your on-farm propane dryer costs less per point removed than that break-even, drying yourself nets more money. Typical variables:

• Propane cost — the biggest swing factor; a $0.30/gallon change can flip the decision.
• Drying shrink loss — grain loses about 1–1.5% of weight per point of moisture removed (the “drying conversion factor”).
• Elevator handling shrink — usually 0.5 to 1.5%; some elevators include it in a flat shrink-per-point schedule rather than a separate line.
• Storage interest cost — if you dry and store waiting for a better price, the interest on the grain’s value accumulates.

What to watch on the settlement sheet

Elevators sometimes calculate shrink using a flat factor (for example, 1.4% of wet bushels per point over standard) rather than the volumetric formula above. The two methods produce slightly different results, especially at high moisture levels above 20%. Always reconcile the tool’s estimate against the actual settlement ticket, paying attention to whether the elevator used a volumetric shrink formula or a flat-factor schedule.

Test weight is another surprise: low-test-weight corn (below 54 lb/bu) reduces your bushel count even after moisture correction, since the elevator may apply a test weight discount on top of the moisture dockage. Enter your actual meter test weight — not the nominal 56 lb — for an accurate bushel count.