1. Dry matter stays constant
Exact water shrink assumes drying removes water but no grain solids. Initial dry matter is divided by the dry-matter fraction at target moisture.
Grain Moisture Shrink and Drying Cost Calculator
Estimate how many dry bushel equivalents remain after moisture removal, then compare exact water shrink, physical handling loss, and an elevator’s commercial pencil-shrink factor.
Load and Moisture Inputs
Presets are editable planning values, not contract terms.
Used to convert weight to bushel equivalents.
Shrink Settlement Method
Percent of original wet weight, added once.
Use the factor published by the buyer.
Physical mode preserves dry matter through the moisture calculation, then subtracts the fixed handling loss once.
Drying Cost and Grain Value
The drying rate is charged on incoming wet bushels for every moisture percentage point removed. Confirm the buyer’s rounding, minimum fees, and charge basis.
Dry Grain and Cost Results
Enter the wet load, moisture readings, and shrink terms to calculate dry grain.
Marketable dry grain (selected method)—
Moisture points removed—
Selected total shrink—
Weight after selected shrink—
Bushels lost—
Drying charge—
Other fees—
Value of grain shrink—
Total shrink + drying impact—
Dry grain value after charges—
| Method | Shrink | Dry bu | Dry weight |
|---|---|---|---|
| Calculate to compare methods. | |||
Water-only shrink follows dry-matter balance. Physical and commercial rows are separate alternatives, not additive deductions.
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How Grain Moisture Shrink Works
2. Handling can remove solids
Breakage, dust, foreign material, respiration, and spillage can reduce weight beyond water loss. Fixed handling loss is applied once to incoming wet weight.
3. Pencil shrink is contractual
A buyer may multiply moisture points by one constant factor. That factor can include both water and a handling allowance, so do not automatically add another handling loss.
Formulas and Assumptions
Moisture points removed = initial moisture − target moisture
Water shrink % = moisture points × [100 ÷ (100 − target moisture)]
Water-only dry weight = wet weight × (100 − initial moisture) ÷ (100 − target moisture)
Physical dry weight = water-only dry weight − (wet weight × fixed handling loss %)
Commercial shrink % = moisture points × commercial shrink factor % per point
Drying charge = incoming wet bushels × moisture points × drying rate per wet bushel per point
Bushel results are weight-based equivalents using the entered pounds per bushel. This tool does not predict post-drying volumetric test weight, dockage, grade discounts, basis, taxes, storage charges, or moisture-meter error.
Example: 1,000 Wet Bushels of Corn
For 1,000 wet bushels at 20.5% moisture dried to 15%, exact water shrink is about 6.47%, leaving about 935.3 bushel equivalents before handling loss. Adding a fixed 0.5% of incoming weight leaves about 930.3 bushels. A separate commercial factor of 1.4% per point gives 7.7% shrink and 923.0 settled bushels.
At a drying rate of $0.048 per wet bushel per point, the drying charge is $264.00. These are illustration values only; current buyer terms should replace every preset.
Calculation Basis and References
- Purdue Extension: Calculating Grain Weight Shrinkage in Corn Due to Mechanical Drying — water-shrink factor, handling loss, drying-table, and constant-factor methods.
- Iowa State University Extension: Grain Drying Considerations — worked wet-bushel drying-charge and shrink examples.
- University of Minnesota Extension: Energy Costs for Corn Drying and Cooling — per-bushel-per-point energy cost framework and the importance of actual dryer records.
References explain the calculation methods, not universal rates. Moisture targets, test weights, charges, and settlement rules vary by grain, grade, location, buyer, and contract.
FAQs
What is the formula for grain moisture shrink?
Water shrink percent equals the points removed multiplied by 100 ÷ (100 − final moisture). The equivalent weight formula is wet weight × (100 − initial moisture) ÷ (100 − final moisture).
What is the difference between water shrink and commercial pencil shrink?
Water shrink is the mathematically required water loss. Commercial pencil shrink uses a buyer’s percentage per point and may include handling or storage allowances.
How is grain drying cost calculated?
A common method is wet bushels × moisture points removed × drying rate per wet bushel per point. This page also supports another per-bushel fee and a flat extra cost.
Does test weight change the shrink percentage?
No. Moisture balance determines shrink percentage. The entered bushel weight converts pounds to bushel equivalents and therefore affects quantity results when the load is entered by weight.
Should handling loss be added to a commercial shrink factor?
Usually not unless the buyer explicitly says the factor excludes handling. Commercial shrink commonly includes a handling allowance, so the calculator treats physical and commercial methods as separate alternatives.
Why might the elevator settlement differ?
Elevators can use different targets, shrink tables, rounding, minimum charges, discounts, test weights, and fee schedules. Use the current bid sheet or settlement contract values.
Are my load and price inputs stored?
No. Calculations run entirely in the browser, and this tool does not send or store entered values.
Planning Limits
This calculator is a budgeting and settlement-comparison tool, not a grain-storage safety recommendation. Safe storage moisture depends on grain type, temperature, storage duration, aeration, grain condition, and local conditions. Verify drying targets and storage practices with your buyer, insurer, grain-storage professional, or local extension service.