Calculate corn stocks-to-use from a dated balance sheet

Identify the numerator and denominator

For the U.S. corn balance, use ending stocks and total use from the same marketing-year column in the same WASDE edition. Keep both in the same unit, such as million bushels. Dividing a world stock figure by U.S. use or mixing May stocks with August use produces a ratio with no coherent source definition.

Total use includes the table’s relevant domestic and export categories. It is not interchangeable with domestic consumption alone. The choice matters because a different denominator can change the result substantially without any change in the physical stock estimate. Retain the component table or exact total used so the ratio is independently reproducible.

Reproduce the two 2024 forecast vintages

USDA’s May 10, 2024 WASDE 648 table projects 2024/25 U.S. corn ending stocks of 2,102 million bushels and total use of 14,805 million bushels. Dividing and multiplying by one hundred gives approximately 14.197906 percent. These are that edition’s forecasts for the stated marketing year.

The August 12, 2024 WASDE 651 edition gives 2,073 million bushels of ending stocks and 14,965 million bushels of total use for 2024/25. The corresponding ratio is approximately 13.852322 percent. The difference is about minus 0.345584 percentage points, not minus 0.345584 percent in relative terms.

Explain why both sides of the ratio matter

Between those editions, ending stocks decline by twenty-nine million bushels while total use rises by 160 million. Both changes contribute to the lower ratio. Looking only at the stock revision would miss the denominator’s role. A ratio is a compressed summary of the balance, so keep the original quantities beside it.

In a separate invented example, unchanged stocks of two billion bushels with use rising from ten to twelve billion reduce stocks-to-use from twenty percent to about 16.667 percent. No inventory disappearance is implied by that comparison alone; the denominator changed. The example illustrates why a lower ratio needs a balance-sheet explanation.

Avoid treating the ratio as available days of supply

Multiplying an annual stocks-to-use ratio by 365 can create a rough days-equivalent under uniform-use assumptions. It does not establish actual delivery availability through the year. Demand is seasonal, stocks are geographically distributed and quality or logistics can constrain access. The ratio lacks those details.

A low ratio can motivate closer investigation of the balance and uncertainty, but it does not determine a unique price. Expectations, substitutes, trade conditions and the timing of use also matter. This publication does not fit a price equation or infer an investment return from the reported ratio.

Keep forecast and realized evidence separate

The May-to-August comparison concerns revisions to forecasts, not final realized 2024/25 stocks or use. It should not be described as evidence that the eventual season became tighter by exactly the displayed amount. A realized-outcome study would require a separately identified later estimate and its own revision context.

The lab requires nonnegative ending stocks and positive total use for its simple calculation. It does not repair incompatible units or identify the correct table automatically. A credible dossier retains edition dates, marketing year, table location, quantities and formula so readers can assess both the arithmetic and the scope of the claim.

Keep in the decision record

• Use the same geography, marketing year and forecast vintage.
• The May-to-August ratio change is about minus 0.345584 percentage points.
• Stocks-to-use is not a deterministic price rule.

Source notes

1. USDA WASDE 648 — 10 May 2024, U.S. corn table, printed page 12
2. USDA WASDE 651 — 12 August 2024, U.S. corn table, printed page 12
3. USDA ERS — Feed Grains Database documentation, reviewed 16 October 2026

Source dates and scope matter. Historical inventory observations are retained snapshots; forecasts and synthetic curve assumptions are labelled separately. No investment outcome or product coverage is implied.

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