Grain Moisture Shrink Calculator (Dry Bushels, Shrink % & Drying Cost)

How it works

dry weight = wet weight × (100 − moisture_in) ÷ (100 − moisture_target) · handling loss = wet weight × handling % · net = dry weight − handling loss (dockage taken off the gross weight first) · true shrink % per point = 100 ÷ (100 − target) (corn 1.183 at 15.5%, soybeans 1.149 at 13%) · bushels = lb ÷ standard bushel weight (corn 56, soy/wheat 60) · elevator credits = wet bu × (1 − shrink factor × points over its base − handling allowance), points optionally rounded up to the half point · drying charge = wet bu × points × rate · net = credited bu × price − drying charge

Grain is bought on a dry-matter basis expressed as bushels at a standard moisture, so a load that arrives wet is worth only the dry matter it contains: removing water shrinks the weight by a little more than one percent for every point of moisture, plus a small loss of fines in handling. Enter the load as a wet weight or as wet bushels from the scale ticket. Elevators simplify the arithmetic into a flat shrink factor per point that usually exceeds the physical shrink, often shrink to a lower base than the grade standard (15.0% instead of 15.5% for corn), round partial points up to the half point and add a drying charge per point — all of which can be set under More options, together with dockage and a separate handling allowance. The result compares what the elevator credits with the physical dry bushels, and what the load nets delivered wet with drying it on the farm and selling it dry. Turn on the second buyer to compare two schedules: a lower shrink factor can still pay less if that buyer shrinks to a lower moisture. The same arithmetic warns against over-drying, since every point below the standard is dry matter given away.

Worked example

A 50,000 lb load of corn at 22% is 893 wet bushels; dried to 15.5% it weighs 46,154 lb — 45,904 after a 0.5% handling loss (250 lb) — or 820 dry bushels, a shrink of 8.19%. An elevator at 1.4% per point credits only 812 bushels and charges about $261 to dry 6.5 points, netting about $3,391; drying on farm at 2.5¢ a point costs about $145, leaving about $3,543 from the dry grain, so home drying is worth roughly $152 on the load before dryer overheads. Purdue’s comparison of two buyers for 100,000 lb of 20% corn is reproduced with the second-buyer option: 1,652 bu at $2.50 with a 1.25 factor to 14% ($4,130) against 1,633 bu at $2.55 with true shrink to 13% plus 0.5% handling ($4,165).

Sources: Purdue Extension NCH-61 — Grain shrinkage due to drying · Penn State Extension — Understanding grain discount schedules

Frequently asked questions