Why Don't Gas Station Prices Rise Immediately When Global Oil Prices Exceed 100 a Barrel? 4 Factors to Watch Before the 2–3-Week Lag
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Even when WTI and Brent crude exceed 100 per barrel, gasoline prices at South Korean gas stations do not necessarily jump by the same percentage the following day. Several factors stand between international crude oil prices and domestic consumer prices: international refined petroleum product prices, the won-dollar exchange rate, refinery supply prices, and gas station inventories. In September 2026, the petroleum price ceiling system is also influencing prices.
According to nationwide average prices published by the Korea National Oil Corporation as of September 11, gasoline costs KRW 1,858.80 per liter, while automotive diesel costs KRW 1,843.44. Meanwhile, as of September 10, WTI had climbed to 102.48, and Brent crude had reached 107.63.
Why Are Gasoline Prices Holding Steady Even Though Global Oil Prices Have Exceeded 100?
The main reason is that crude oil that becomes more expensive today does not reach gas stations today.
Domestic gasoline prices are not determined simply by converting crude oil prices directly into local currency. Refiners import crude oil and process it into gasoline and diesel, which then pass through domestic distribution channels before being sold at gas stations.
It is commonly estimated that changes in international refined petroleum product prices take approximately 2–3 weeks to appear in domestic gas station prices. However, this is not a fixed formula indicating that prices will always move exactly 14 days or 21 days later. The adjustment may happen sooner or later depending on inventories, the speed of refinery supply price changes, exchange rates, and government measures.
Therefore, a rise of more than 6% in international oil prices within a single day as of September 10 does not mean nationwide gas station prices as of September 11 will also increase by 6%.
Watch International Gasoline Prices Alongside Crude Oil Prices
To understand what drivers may actually pay, it is important to monitor international refined petroleum product prices, rather than relying solely on WTI or Brent crude.
The Korea National Oil Corporation's Opinet service separately publishes international prices for refined petroleum products, including gasoline and diesel, traded in the Singapore market.
As of September 9, the international gasoline price for 92RON was 132.32 per barrel, while 95RON was 136.61. Ultra-low-sulfur diesel was 171.18. Dubai crude was 122.01 on the same day.
In other words, the following sequence provides a clearer understanding of domestic fuel prices:
**Rising international crude oil prices
→ Changes in refined gasoline and diesel prices
→ Exchange rate adjustments
→ Domestic refinery supply prices
→ Gas station inventory turnover
→ Consumer prices**
Crude oil and gasoline prices do not always move by the same percentage. Depending on refinery operating conditions, gasoline and diesel demand, and shortages of particular petroleum products, refined product prices may rise either more or less sharply than crude oil prices.
In 2026, the Petroleum Price Ceiling System Makes the Lag More Complicated
There is currently another factor that makes the situation different from normal market conditions.
The Ministry of Trade, Industry and Resources froze the 9 round of petroleum price ceilings, which took effect on August 22 and applied for 4 weeks. At the time, the maximum refinery supply prices were set at KRW 1,784 per liter for gasoline, KRW 1,773 for diesel, and KRW 1,380 for kerosene.
One common misunderstanding needs to be clarified.
KRW 1,784 is not the maximum gasoline price that gas stations nationwide are allowed to charge consumers.
The ceiling specified in government materials applies to refinery supply prices. Therefore, the nationwide average gasoline price of KRW 1,858.80 as of September 11 does not mean gas stations are violating the price ceiling system.
Gas station retail prices include additional distribution and sales costs, so refinery supply prices and consumer prices should not be compared as though they represent the same pricing stage.
If international oil prices remain at their current levels for an extended period, the next decision on price ceilings could become an important factor affecting domestic consumer prices.
So Exactly When Will Gas Station Prices Rise?
It is difficult to determine a specific date in advance.
As of the morning of September 11, the nationwide average gasoline price was KRW 1,858.80, up KRW 0.11 from the previous day, while diesel was KRW 1,843.44, up KRW 0.58. In other words, even immediately after international oil prices surged by more than 6%, domestic average prices had not yet shown a comparable increase.
Going forward, it is useful to monitor the following four indicators together.
| Indicator to Check | Why It Matters |
|---|---|
| International gasoline and diesel prices | More directly linked to domestic supply prices |
| Won-dollar exchange rate | The cost in Korean won changes even when the dollar-denominated price stays the same |
| Refinery supply prices | Directly affect gas stations' purchasing costs |
| Nationwide average gas station prices | Represent the final prices consumers actually experience |
In particular, what matters in a situation like this is whether the rise in international oil prices turns out to be a one-day spike or persists for several days or weeks.
If prices surge for a day and then decline, the impact on domestic prices may be limited. However, if elevated crude oil prices persist and international gasoline and diesel prices also rise, upward pressure on domestic fuel prices will increase.
How Much More Would a Fill-Up Cost If Gasoline Prices Rose by KRW 100?
The additional cost can be calculated simply by multiplying the increase per liter by the amount of fuel purchased.
For example, for a vehicle receiving 50 liters of fuel:
KRW 100 × 50 liters = KRW 5,000
Using the nationwide average gasoline price of KRW 1,858.80 as of September 11, purchasing 50 liters would cost approximately KRW 92,940.
According to the author's calculations, if gasoline prices increased by KRW 100 per liter, the cost of the same 50-liter fill-up would become KRW 97,940. If prices increased by KRW 200, the cost would become KRW 102,940.
| Assumed Gasoline Price | Cost of 50L of Fuel |
|---|---|
| KRW 1,858.80 | KRW 92,940 |
| KRW 1,958.80 | KRW 97,940 |
| KRW 2,058.80 | KRW 102,940 |
These figures are simple illustrations of how price changes affect fuel expenses, not forecasts of future prices.
Why You Cannot Simply Calculate Gasoline Prices as 'WTI at 100 Means Gasoline at KRW 2,000'
Directly converting the price of a barrel of crude oil into a domestic gasoline price is not accurate.
The international price of a barrel of crude oil does not include domestic refining and distribution costs, and an entire barrel of crude oil is not converted into gasoline. Exchange rates, international prices for individual petroleum products, taxes, distribution costs, and each gas station's inventories and profit margins also vary.
Therefore, there is no single conversion formula that can tell you how many Korean won gasoline should cost when WTI reaches 100.
If you want to estimate actual fuel expenses, it is more useful to check the following information on Opinet in this order rather than focusing on the WTI price alone:
International refined petroleum product prices → Changes in refinery supply prices → Nationwide average gas station prices
In September 2026, you should also check whether the government adjusts its petroleum price ceilings.
Which Figures Should You Check First Right Now?
As of September 11, there is a substantial gap between movements in international crude oil prices and domestic gas station prices.
WTI has surged to 102.48, and Brent crude has reached 107.63, but the nationwide average gasoline price remains around KRW 1,858.80. It is difficult to conclude that the international oil price increase has already been fully passed on to domestic consumers.
If you are concerned about future fuel costs, it is more useful to monitor how long international gasoline and diesel prices remain elevated, rather than focusing solely on WTI crossing 100. You should also watch whether domestic refinery supply prices and nationwide average gas station prices actually begin trending upward.
A sharp increase in international crude oil prices creates upward pressure on domestic fuel prices, but neither the size nor the timing of a domestic price increase can be determined from the crude oil price alone.
※ This article is provided for informational purposes to help readers understand market trends and does not constitute investment advice concerning any particular security or asset. Readers are responsible for their own final decisions and investment outcomes.
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