Grain Moisture Shrink: How to Calculate Dry Weight and Yield
Grain sold above the standard moisture is paid as if it were drier — the buyer deducts the extra water. Knowing the formula lets you check settlement sheets and decide whether to harvest now or wait.
The moisture shrink formula
dry weight = wet weight × (100 − harvest moisture) ÷ (100 − standard moisture)
The dry matter stays the same; only the water changes. Many buyers also discount impurities above a tolerance and may add a handling charge — check your contract.
Worked example
A truckload of soybeans: 30,000 kg at 18% moisture, with 2% impurities. Standard: 14% moisture, 1% impurity tolerance.
- Impurity discount: 2% − 1% = 1% → 30,000 × 0.99 = 29,700 kg.
- Moisture: 29,700 × (100 − 18) ÷ (100 − 14) = 28,319 kg.
That's about 1,040 bushels of soybeans (27.22 kg each) or 472 bags of 60 kg. The yield and moisture calculator does this and divides by the harvested area to give yield per hectare.
Units
| Unit | Weight |
|---|---|
| Bushel of soybeans or wheat | 27.22 kg (60 lb) |
| Bushel of corn | 25.40 kg (56 lb) |
| Saca (Brazil) | 60 kg |
| Tonne | 1,000 kg |
Harvest now or let it dry?
Every point of moisture above standard costs roughly 1.2% of weight in shrink, plus any drying fee. Waiting lowers moisture but risks field losses, weather damage and lodging. Run both scenarios and compare the numbers.
To turn yield into profit per hectare, use the crop cost and profit calculator.