Grain shrink calculator: what delivering wet grain actually costs
Put in how much you are hauling and at what moisture. This works out the weight you get paid on, what the shrink costs at your price, and the drying charge on top.
Extra loss some buyers take on top. Often 0.5% in the US.
Only used with a fixed factor.
How moisture shrink is worked out
Grain is paid for on its weight at a base moisture. Anything above that is water, and the buyer takes it off before paying. The water-loss formula is:
shrink % = (moisture at delivery − base moisture) ÷ (100 − base moisture) × 100
So 100 tonnes of spring wheat delivered at 18% against a 14.5% base loses 3.5 ÷ 85.5 = 4.09%. You are paid on 95.9 tonnes. It is not simply 3.5%, because the base itself contains water: each point you dry off removes a little more than one percent of the weight.
Many US elevators skip the formula and use a fixed factor per point — often 1.3% to 1.5% a point for corn. At a 15.5% base the pure water loss is about 1.18% a point, so a 1.4 factor quietly carries roughly 0.2% a point of handling shrink. Worth knowing when you compare buyers.
Typical base moisture by crop
Starting points only. Canadian figures are the top of the "dry" range in the Canadian Grain Commission's tough and damp moisture ranges, checked 25 September 2026. US figures are common market standards, shown only where one is widely used. Where we could not confirm a figure, the table says to ask your buyer.
| Crop | Canada, dry at or below | US market standard |
|---|
Questions
Is it cheaper to dry it myself or let the elevator do it?
The water is lost either way — shrink is physics, not a fee. What differs is the drying charge, any extra handling shrink the buyer adds, and whether they will take tough grain at all in a busy week. Put the elevator's drying charge in above and compare the last box against your own fuel, power and time.
Why does the shrink look bigger than the moisture difference?
Because the base moisture is itself a share of the weight. Taking grain from 18% to 14.5% removes 3.5 points of water from a total that is only 85.5% dry matter, so the weight falls by 4.09%, not 3.5%.
Does shrink apply to bushels or weight?
Weight. Grain is bought on weight and converted to bushels at the standard bushel weight for the crop, so a 4% shrink is 4% of the tonnes and 4% of the bushels alike.
Shrink is where the contract price leaks
GrainPosition keeps every load ticket against the contract it went on, with moisture and dockage, and shows what you contracted at against what you were actually paid. It tracks bins and your weighted average in tonnes or bushels too.
There is a live demo with nothing to sign up for.
Have a look