Market Data

Propane at $0.68: The Feedstock Math Behind U.S. Plastics Margins

Propane is the feedstock behind propylene and much of the resin chain. We trace what the Mont Belvieu spot means for petrochemical and plastics manufacturers' input costs.

Mont Belvieu propane at $0.68/gal as of Jul 6, 2026 sets the feedstock cost for propane dehydrogenation units and flexible steam crackers, the plants that turn the gallon into propylene and, one step downstream, into the polypropylene and other resins U.S. plastics processors buy. With the benchmark sliding and with no prior-year reading archived yet, the input bill for the propylene chain is moving, and the effect works its way from the Gulf Coast hub to the resin invoice with a lag measured in weeks to months.

From gallon to pellet

Two routes carry propane into the plastics chain. Propane dehydrogenation, or PDH, strips two hydrogen atoms from propane to make on-purpose propylene; a wave of U.S. PDH plants built over the past decade runs on Mont Belvieu-priced feedstock by design. Steam crackers with feed flexibility can also swing between ethane, propane, and butane depending on relative prices, cracking propane when it is the cheap barrel. Propylene then polymerizes into polypropylene, the resin in automotive parts, packaging, appliances, and fibers, or feeds acrylonitrile, propylene oxide, and other intermediates. Every step marks up the molecule, but the starting price is the hub print.

The margin math

Propane weighs about 4.24 pounds per gallon, and a PDH unit consumes roughly 1.2 pounds of propane per pound of propylene. At the current $0.68/gal, that puts the raw feedstock cost near 19.1 cents per pound of propylene, before conversion costs and byproduct credits. Scale it up: a world-scale PDH unit making 1 billion pounds of propylene a year buys about 283 million gallons of propane, a feedstock bill of roughly $191,320,755 at today's hub price. Every nickel the benchmark moves swings that bill by about $14,150,943 a year. That is the transmission mechanism from the daily spot print to propylene contract prices, and from there to resin.

Mont Belvieu propane spot, Jul 6, 2026: $0.68/gal. Ranged from $0.67 (Jul 2, 2026) to $0.79 (Jun 10, 2026) across the archived history. The latest print sits in the lower third of that range.

Every nickel on the Mont Belvieu print moves a world-scale PDH unit's feedstock bill by eight figures a year, and resin buyers inherit the tail of that move.

Who captures the move

The benefit or pain of a feedstock move is not shared evenly. Integrated producers, those who make propylene and polymerize it, capture margin first, because propylene contract prices reset monthly while resin list prices move slower and stickier. Non-integrated resin converters see the effect only when producer price indexes for plastic resins catch up, typically one to three months behind the hub. For a plastics processor, the practical play is to track the propane print as a leading indicator for resin-price negotiations: when the feedstock has moved and the resin quote has not, that gap is negotiating room. The archived propane series and the resin PPI series together tell you whose margin is holding the difference at any moment.

Put your resin price and part weight into the resin cost per part calculator to see what a feedstock move is worth on each molded piece. Trace it to your part cost

Published 2026-07-13.