Unleaded Regular Gasoline against the WTI crude price, both set to 100 in the first month they share
Sep 2026WPU057104 219WTI crude price 185
Sources: WPU057104 (Unleaded Regular Gasoline); EIA via FRED, MCOILWTICO.
Since 2017, this index has followed the WTI crude price in the same month and moved about as far as it over a year.
Over the 12 months to Sep 2026, the WTI crude price rose 52.1% and this index rose 66.1%.
Key figures
Since Jan 2017
+118.8%
161.4 to 353.2
12-month volatility
±12.6%
std. dev. of monthly change
Largest monthly rise
+49.1%
May 2020
10% cap would bind
21 of 36
months, annual base reset
From Jan 2017 to Sep 2026 the index went from 161.4 to 353.2, a change of +118.8%.
Highest reading in that period: 407.9 in Jun 2022. Lowest: 57.8 in Apr 2020.
Largest one-month rise: +49.1% in May 2020. Largest one-month fall: -54.3% in Apr 2020.
For a clause that resets its base every year, a 10% cap or floor would have limited the adjustment in 21 of the last 36 months.
Use it in a contract
Draft clause citing this series
A starting point citing this series by name and code. Replace the bracketed terms with your contract's actual scope before use.
The [affected portion] of the Contract Price shall be adjusted using US PPI — Unleaded Regular Gasoline (BLS series WPU057104), published by BLS.
Base Period: the index value published for September 2026 (or the month of contract signing, if different) is the Base Value.
Adjustment: at each Adjustment Date, the Current Value is the most recently published three-month average of the index (the Averaging Window). The Escalation Factor equals Current Value divided by Base Value.
Cap: the Escalation Factor applied under this clause shall not exceed 1.10 or fall below 0.90 (a 10% cap and floor) in any single Adjustment Date, regardless of the index's actual movement.
[Replace bracketed terms with your contract's actual affected-portion definition and adjustment-date schedule before use. This is a drafting starting point, not legal advice.]
A diesel fuel surcharge compares a current-period Producer Price Index value for No. 2 diesel fuel to the value at contract signing (the base period), turns that into a ratio, then applies the ratio, often above a threshold, to the freight or transport-affected portion of the contract price. Clauses typically name the exact BLS series code, an averaging window, a publication lag, and a cap limiting the maximum adjustment.
Let Escalake run this clause for you
Escalake tracks US PPI — Unleaded Regular Gasoline, applies your formula, and gives both sides a number they can confirm, no spreadsheet required.