Following the successive departures of Audi and Porsche from the WEC at the end of the 2016 and 2017 seasons — partly as a consequence of the Volkswagen emissions scandal and partly due to the enormous development costs of the LMP1-H era — the ACO began discussions with manufacturers and series stakeholders about a new top-class formula. The stated goal was to reduce full-season budgets by up to 75% compared to the LMP1-H era, targeting a total of approximately 25 million euros, while maintaining genuinely high performance and attracting multiple manufacturers.
Initial discussions were announced ahead of the 2018 24 Hours of Le Mans, with Toyota, Ford, McLaren, Aston Martin, and Ferrari identified as participants in early roundtable conversations. Scuderia Cameron Glickenhaus became the first manufacturer to formally commit in July 2018.
The full LMH technical rulebook was published by the FIA in December 2018, with significant revisions announced in 2019 and 2020. Key parameters of the final regulations include a maximum combined power output of 500 kW from the combustion and hybrid systems together, with the optional electric motor-generator limited to 200 kW on the front axle — giving cars four-wheel drive when the hybrid system is active. The combustion engine must use a four-stroke petrol architecture and may use any number of cylinders, with turbocharged or naturally aspirated designs both permitted.
For production-based powertrains, the block and head castings must originate from the road car's base engine, with modifications limited to specific machining tolerances. This requirement links the race car to a manufacturer's road car programme, reinforcing the hypercar concept. Manufacturers are required to produce a minimum of 25 road-legal versions using the race car's combustion engine and energy-recovery system by the end of their first competitive season, rising to 100 by the end of the second season.
Cars have a minimum weight of 1,030 kg and a maximum length of 5,000 mm. Diesel power is banned. The aerodynamic regulations require all mechanical components to be covered by bodywork, and movable aerodynamic devices are prohibited. The frontal surface area must be at least 1.6 square metres.
In 2021, ahead of the Peugeot 9X8 reveal and in the same period that the first LMH cars were racing, the IMSA and the ACO announced a merger of their prototype rulesets. The resulting alignment created a single combined class: Le Mans Hypercar in the WEC and Grand Touring Prototype in the IMSA SportsCar Championship. Le Mans Daytona h (LMDh) cars — a separate specification allowing constructor chassis from approved suppliers — can race alongside LMH cars in both championships. From 2023, the full Hypercar field in the WEC comprises both LMH and LMDh cars competing under a shared Balance of Performance framework.
The Hypercar class debuted at the 2021 24 Hours of Le Mans. Toyota entered with the GR010 Hybrid, which won the race. Alpine fielded an LMP1-derived car in the early seasons. Ferrari debuted the 499P in 2023 and won Le Mans at its first attempt. Peugeot entered with the 9X8 before withdrawing from the programme. Porsche and BMW returned to top-level endurance racing via the LMDh pathway.
Aston Martin, initially committed to the Hypercar class using the Valkyrie road car as its basis, postponed its programme in February 2020 following the announcement of the LMDh rules, which offered a different pathway to entry. The class subsequently attracted entries from Toyota, Ferrari, Cadillac, Porsche, BMW, Lamborghini, Alpine, and others across the LMH and LMDh pathways.
The ACO targeted a 3:30 lap time at the Circuit de la Sarthe for Hypercar cars, compared to around 3:15 for the fastest LMP1-H cars. This deliberate performance reduction was intended to make competition closer and reduce the mechanical and aerodynamic development arms race that had characterised the LMP1-H era. A Balance of Performance system is applied to ensure competitive racing between different manufacturers and between LMH and LMDh cars.
The Le Mans Hypercar regulations succeeded in returning multiple manufacturers to the top class of endurance racing within a few seasons of their introduction, reversing the single-manufacturer situation that had prevailed at the end of the LMP1-H era. The requirement for production-based engines and road car production links the racing programme to road car development in a way that appeals to manufacturers seeking dual returns on investment. The successful convergence with LMDh also restored a level of parity between the European WEC and North American IMSA championships, enabling manufacturers to compete in both series with the same car.