Flight time: Seoul to Chicago

Route details

Distance breakdown: Seoul to Chicago

The 10,521-km great-circle distance between Seoul (37.46°N, 126.44°E) and Chicago (41.97°N, 87.91°W) spans 4.5° of latitude and 214.3° of longitude, trending primarily west. In miles, this is 6,537 mi or 5681 nautical miles. The great-circle path — the shortest distance over Earth's curved surface — is calculated using the Haversine formula from the two airports' precise coordinates.

Cruise speed and flight phases

On this 10,521-km long-haul route, aircraft spend the majority of the 12h 11m to 13h 40m journey at optimal cruise altitude of 35,000–42,000 feet, where modern wide-body jets achieve true airspeeds of 820–900 km/h (Mach 0.82–0.86). The initial climb and final descent represent a smaller fraction of total flight time compared to shorter routes. Aircraft like the Boeing 777, 787, or Airbus A350 typically operate routes of this distance, with step climbs during the flight to reach progressively more efficient altitudes as fuel burns off and the aircraft lightens.

Ground time and routing overhead

Our 30–50 minutes overhead allowance covers: taxi-out at ICN, takeoff and initial climb, descent and approach at ORD, and taxi-in to the gate. ICN is a major international hub where taxi times of 15–25 minutes are common during peak periods. At ORD, arrival taxi and gate assignment can add 10–20 minutes, especially during busy arrival banks. Oceanic tracks between Seoul and Chicago follow organized route systems (like the North Atlantic Track system) that may add 5–10% to the theoretical great-circle distance. These tracks are assigned daily based on forecast winds.

Return flight: Chicago → Seoul

The return flight from Chicago to Seoul differs noticeably in duration due to upper-atmosphere wind patterns along this oceanic corridor. The jet stream — a high-altitude river of fast-moving air flowing generally from west to east — creates an asymmetry: the eastbound leg (Chicago to Seoul if eastbound, otherwise Seoul to Chicago) is typically 20–60 minutes shorter. Airlines adjust fuel loads and even routing to account for this, sometimes flying more southerly or northerly tracks on the headwind leg to minimize the impact. Over a year, the average time difference between the two directions on this specific route is estimated at 30–45 minutes.

Seasonal variation in flight times

Pacific routes between Seoul and Chicago experience significant seasonal variation. The Pacific jet stream can exceed 350 km/h in winter at altitudes around 30,000–40,000 feet, creating flight time differentials of over 1 hour between eastbound and westbound legs. During typhoon season (June–November), routing diversions in the western Pacific may add distance. Winter storms in the North Pacific can also cause turbulence-related route adjustments. The most stable and predictable flight times on this corridor occur in spring (March–May) and autumn (September–November).

Airport information

Incheon International Airport (ICN) is a major international hub in Seoul, South Korea. As a tier-1 airport, it handles high traffic volumes, which means longer average taxi times but also higher flight frequency and competition that can benefit travelers on pricing. O'Hare International Airport (ORD) is a major international hub in Chicago, United States. As a tier-1 airport, it handles high traffic volumes, which means longer average taxi times but also higher flight frequency and competition that can benefit travelers on pricing.

Flight times from Seoul to other destinations

Flight time FAQ: Seoul to Chicago