How Oil Prices Change: Brent, WTI and Today's Drivers

Oil prices change because traders in the futures market continuously revise their view of how much crude will be available against how much will be needed, so the number you see quoted is almost always the front-month futures contract on Brent or West Texas Intermediate (WTI) repricing second by second, not a price set by a producer or a government. On Friday, September 18, 2026, CNBC reported that WTI futures fell 1.6% to close at $100.30 a barrel and Brent, the international benchmark, settled 0.9% lower at $103.87, in a week when prices had run more than 5% higher after a drone attack shut a Saudi pipeline before giving some of that back.

Quick answer

• The mechanism: price changes come from shifts in expected supply and demand, expressed through futures contracts; the EIA lists OPEC and non-OPEC supply, OECD and non-OECD demand, inventories and financial markets as the drivers.
• Oil price today (September 18, 2026 settlements): WTI $100.30/b, Brent $103.87/b, per CNBC's market report; both benchmarks trade continuously, so any quote needs a timestamp.
• The official forecast is lower than the market: the EIA's September 2026 Short-Term Energy Outlook, with model inputs finalized on September 3, 2026, sees Brent averaging about $90/b in the second half of 2026 and falling to roughly $74/b in 2027. It does not account for market events after that date.
• The recurring catalyst: the EIA's Weekly Petroleum Status Report is normally released Wednesdays at 10:30 a.m. Eastern, and inventory builds or draws against expectations move crude prices immediately.
• Scale of a move (our arithmetic, not a forecast): a barrel is 42 US gallons, so a $10/b change equals about 23.8 cents per gallon of crude cost before refining margins, distribution and taxes.

What "the oil price" actually refers to

There is no single global oil price. There are benchmark grades, and the two that dominate quotes are Brent, which prices much of internationally traded crude, and WTI, the North American benchmark delivered at Cushing, Oklahoma. When a headline says oil rose or fell today, it almost always means the front-month futures contract on one of those two: the contract closest to expiry, which is why a "continuous" chart is really a chain of contracts spliced together as each one rolls.

Two prices sit alongside each other. The spot price is what a physical cargo changes hands for now; the futures price is what a contract for delivery in a later month costs. The EIA describes the link between them through storage: if futures prices rise relative to spot, the incentive to store oil and sell later strengthens, while a visible increase in stored crude signals that production is running ahead of consumption at the prevailing price, which tends to pull spot prices down until supply and demand rebalance.

The gap between the two benchmarks also moves. In its April 2026 outlook the EIA noted that Brent rose more sharply than WTI because of exposure to higher shipping costs and reduced flows between the Middle East and Asian consuming markets, and projected the Brent-WTI spread peaking near $15/b when production disruptions were largest before narrowing as Strait of Hormuz flows resumed. On September 18, 2026, the gap implied by the two settlements above was $3.57.

Oil price today and the forecast path

The table separates observed prices from forecasts. Settlements are market outcomes on a stated date; the 2026 and 2027 figures are EIA projections that change every month.

Read the mismatch carefully. Brent traded above $103 on September 18 while the EIA's second-half forecast sits near $90. That is not necessarily an error in either number: the STEO's inputs were finalized on September 3, and the agency states the forecast does not specifically account for market events after that day, including the pipeline outage that lifted prices in the following two weeks. A monthly forecast average and a single day's settlement answer different questions.

The reason prices are high relative to recent years, according to the September 2026 STEO, is supply loss rather than a demand boom. The EIA attributed August's increase to constrained Middle East exports and resulting production shut-ins, tied in part to the renewed US blockade on Iran's oil exports after attacks on tankers in the Strait of Hormuz and new sanctions from the Treasury's Office of Foreign Assets Control, and expects regional production to stay below pre-conflict averages into the second quarter of 2027. JPMorgan's head of global commodities strategy, Natasha Kaneva, wrote in a September 18 note cited by CNBC that Middle East flows had averaged about 17 million barrels per day over the prior 10 days, roughly 6 million b/d below the 2025 average. That is a bank's estimate, not an official statistic.

What moves the price, and how quickly it shows up

The EIA groups the drivers into supply from OPEC countries, supply from non-OPEC countries, the supply-demand balance visible in inventories, demand in OECD and non-OECD economies, and financial markets. Those categories act on very different clocks.

One caution on causation: a headline and a price move that happen on the same morning do not establish that one caused the other. Prices also move on positioning, expiries and revisions to earlier assumptions, and several drivers frequently pull in opposite directions in the same session.

The release calendar that prices trade around

Much of the week's volatility clusters around scheduled data. The EIA states that the Weekly Petroleum Status Report is usually released Wednesdays at 10:30 a.m. Eastern, with a holiday schedule that can shift it. In the report retrieved for this guide, covering the week ending August 21, 2026, commercial crude inventories excluding the Strategic Petroleum Reserve rose 0.1 million barrels to 428.9 million, about 1% above the five-year average for that time of year, while gasoline stocks fell 2.5 million barrels to 6% below the five-year average and distillate stocks fell 2.2 million barrels to about 14% below it.

What matters for the price is the surprise, not the level: a build can be read as bullish if the market expected a larger one. The monthly Short-Term Energy Outlook is the other scheduled item that resets the official supply, demand and price outlook, and each edition states the date its inputs were finalized.

Worked example: turning a $10 barrel move into a household number

This is illustrative arithmetic using a fixed conversion, not a forecast of pump prices.

1. One barrel contains 42 US gallons. A $10.00 per barrel change is $10.00 ÷ 42 = $0.238 per gallon of crude input cost.
2. Assumption: the refining, distribution and tax components of the pump price hold steady and the crude move passes through fully. Under that assumption, pump prices move about 23.8 cents per gallon.
3. Assumption: a household drives 12,000 miles a year at 25 miles per gallon, so it buys 12,000 ÷ 25 = 480 gallons annually.
4. Annual cost effect: 480 × $0.238 = $114.24 per vehicle per year. A two-vehicle household with the same mileage assumption sees about $228.48.
5. Scaling to the move actually observed: Brent's August 2026 monthly average of $91/b was $7/b above July's, which by the same method is $7 ÷ 42 = $0.167 per gallon, or roughly $80 per vehicle per year if sustained for a full year.

Three limits on this example. Pass-through is rarely immediate or complete, because refining margins, regional refinery capacity and state taxes all move independently of crude. The 42-gallon barrel yields multiple products, so gasoline does not absorb the whole crude move on its own. And a one-month price change sustained for twelve months is a scenario, not a projection: the EIA's own forecast has Brent declining through 2027, which would reverse part of the effect.

How to read an oil price chart without being misled

A price chart answers a narrower question than most readers assume. Four checks make it usable.

Identify the series. A chart can show Brent or WTI, spot or futures, daily settlements or intraday contract-for-difference quotes from a broker. Those sources disagree by small amounts at any moment. Trading Economics, which tracks the benchmark through a CFD, showed crude at 100.30 on September 18, 2026, down 1.58% on the day, up 18.85% over the prior month and up 60.74% from a year earlier, and separately noted Brent easing below $103 on Friday from a four-month high near $106 on the Tuesday. Those percentage changes describe that series over those windows, and nothing else.

Check the window. The same market in September 2026 was flat over a week, up sharply over a month and far higher over a year. Each statement is true; only together do they describe the market.

Put inventories next to price. The five-year average band in the weekly inventory data tells you whether the current level is tight or comfortable for the season, which is the context a price line alone omits.

Use dated, documented data for anything you rely on. The EIA publishes daily, weekly, monthly and annual petroleum price and stock series on its Petroleum and Other Liquids data pages, which is where a chart from a news site or broker can be checked against the underlying series and its release date.

Two common errors follow from skipping those checks. The first is treating a forecast as a statement about today: the STEO's $90/b second-half average coexists with a $103.87 settlement because they measure different things over different periods. The second is comparing a front-month chart across years without noting that the contract underneath it changed every month.

What to do next

Pick one benchmark, usually Brent for global conditions or WTI for US fuel costs, and check it at the same time each week immediately after the EIA's Weekly Petroleum Status Report lands on Wednesday at 10:30 a.m. Eastern, alongside the inventory change against the five-year average. That single habit tells you whether a price move reflects a physical change in supply or only a change in sentiment.