12 Hours of Sebring: How the Race Works

The 12 Hours of Sebring is a sports-car endurance race with a scheduled duration of 12 hours—not a fixed number of laps. It takes place at Sebring International Raceway in Florida as part of the IMSA WeatherTech SportsCar Championship. The circuit measures 3.74 miles per lap and has 17 turns. IMSA’s event regulations specify both the duration and layout.

The next race, the 75th Mobil 1 Twelve Hours of Sebring, is scheduled for March 20, 2027, with the event running March 17–20. Sebring’s official event page confirms the race date.

How the 12-hour format works

Rather than racing toward a prescribed distance, cars accumulate laps within the allotted time. Under IMSA’s 2026 rules, the winner is the car covering the greatest distance in the shortest official time. Results are ordered by completed whole laps, then finish-line crossing time for cars on the same lap count, subject to penalties. Sporting regulations, Articles 49 and 52.

The finish need not occur at exactly 12:00:00. Article 49.1.1 provides for the leading car to receive the checkered flag as it crosses the finish line at the expiration of the specified duration, as determined by IMSA. Article 49.1 also gives Race Control responsibility for announcing the white flag, which identifies the final lap; the checkered flag follows one lap later, regardless of the overall race time. 2026 sporting regulations. In 2026, the winning car’s official time was 12:01:48.652. Official race results.

Nor does “12 hours” mean 12 hours of uninterrupted green-flag racing. Stoppages can consume the available time: Article 47.5 says overall race time continues during a red flag unless the Race Director announces otherwise. 2026 sporting regulations.

That differs from the distance-led format explained in how long a Formula 1 race is: at Sebring, the duration is specified and the resulting distance varies.

How many laps—and how many miles?

There is no scheduled Sebring lap total. Pace, traffic, pit stops, incidents and neutralizations affect how many laps a car completes.

The 2026 overall winner completed 343 laps. Using IMSA’s published 3.74-mile circuit length:

343 × 3.74 = 1,282.82 miles, or approximately 2,064 km.

That is a calculated distance using the published lap length, not a target distance or an all-time record. Different classes also cover different totals during the same race.

Four classes share the track

IMSA distinguishes two types of machinery: prototypes, designed specifically for racing, and GT cars, based on road-going production models. These form four classes: GTP and LMP2 for prototypes, plus GTD PRO and GTD for FIA GT3-specification cars. Each class has its own classification and winner. IMSA’s class guide.

The latest completed edition was held on March 21, 2026. Its class winners illustrate why overall position and class position must be read separately:

Class	Winning entry	Car	Completed laps
GTP / overall	No. 7 Porsche Penske Motorsport	Porsche 963	343
LMP2	No. 2 United Autosports USA	ORECA LMP2 07	338
GTD PRO	No. 911 Manthey	Porsche 911 GT3 R (992)	321
GTD	No. 21 AF Corse USA	Ferrari 296 GT3 EVO	318

Source: IMSA’s 2026 official results. Felipe Nasr, Julien Andlauer and Laurin Heinrich drove the overall-winning Porsche, which finished 1.515 seconds ahead of the sister No. 6 car. IMSA’s race report confirms the date, winning crew and margin.

Drivers share the workload rather than one person driving for the full duration. For the 2026 event, IMSA set a maximum of seven hours per driver, with no more than four hours in any six-hour period. Sebring supplementary regulations.

When did the race begin?

The first Twelve Hours was held on March 15, 1952, following a six-hour event at Sebring in 1950. The venue’s first race and its first 12-hour race were not the same event. Sebring’s track history.

What is confirmed for 2027?

As of October 19, 2026, the March 20 race date is confirmed, but the circuit’s event page lists the start time as TBD. IMSA’s event page does not yet provide a session or broadcast timetable. Use the official 2027 event listing for schedule updates rather than carrying over 2026’s start time.