What is TheCarCodex?
TheCarCodex brings together official fuel consumption, CO₂ emissions and power figures for cars across five markets: the European Union, the United Kingdom, France, the United States and Canada. Browse by make, model and generation, or search by name, year, engine size or power.
It’s for anyone researching a car they own or are considering, or simply curious about how different models and engines are described in official figures. The site covers 165 makes and 2,094 models, with figures from different years in each market. A model’s generation helps put its figures in context: the same name can span cars with different designs, engines and technology.
How should I read fuel consumption and CO₂ figures?
Fuel consumption figures estimate how much fuel a car uses under a defined test. Depending on the market, they may be shown in litres per 100 kilometres, kilometres per litre or miles per gallon. A lower litres-per-100-kilometres figure means less fuel used over that distance; a higher miles-per-gallon figure means more distance from the same amount of fuel.
CO₂ figures show carbon dioxide emissions per distance travelled, usually in grams per kilometre in European figures. They refer to the tested vehicle and procedure. What you see on the road can vary.
Why do figures differ between markets and on the road?
Authorities use different test procedures. The EU uses WLTP for figures from 2021 onward, while earlier figures use NEDC. The UK uses WLTP from 2018/19, with NEDC used earlier; current French figures use WLTP, with NEDC used earlier. The United States uses EPA testing, and Canada uses a 5-cycle procedure.
Because the procedures differ, figures from different markets are not always directly comparable. Results can also vary by engine and equipment. On the road, traffic, speed, weather, terrain, trip length, load and driving style affect fuel use. An official result is a figure from a defined test for its market, not a prediction for every journey.
Engines and power: what do kW and PS mean?
Kilowatts (kW) and metric horsepower (PS) are two units used to express engine power. Which one appears depends on the market or source. Power is separate from fuel consumption, so a power figure alone does not tell you how much fuel a car will use. Check the engine and generation when looking at figures, as a model name can cover several versions.
What do EU registration counts show?
EU registration counts show how many new cars of a model were registered in the European Union in a given year. They give a view of registrations over time, but do not measure fuel use or CO₂ emissions or explain why a model’s total changed.
Where do TheCarCodex figures come from?
The site brings together figures published by authorities in five markets: EU registrations, the UK Vehicle Certification Agency (VCA), France’s ADEME, the United States Environmental Protection Agency (EPA) and Natural Resources Canada (NRCan). The year ranges differ by market: EU figures run from 2010 to 2025, UK from 2000 to 2026, France from 2012 to 2026, USA from 1984 to 2027 and Canada from 1995 to 2026.
Questions and answers
Are official fuel consumption figures the same as real-world consumption?
No. They come from a defined test. Actual fuel use varies with traffic, speed, weather, route, load and driving style.
Can I compare a European figure directly with a US or Canadian one?
Use care. The EU and current French figures use WLTP, with earlier figures using NEDC; the UK uses WLTP from 2018/19 and used NEDC earlier. The US uses EPA testing, and Canada uses a 5-cycle procedure. Different tests can produce results that are not directly comparable.
What does a lower litres-per-100-kilometres figure mean?
It means the car uses less fuel to travel that distance in the stated test. With miles per gallon, the direction is reversed: a higher number means less fuel used per distance.
What is the difference between kW and PS?
Both are units of power: kW means kilowatts and PS means metric horsepower. They describe engine power, not fuel consumption.
What do EU registration counts tell me?
They show the number of new cars of a model registered in the EU in a given year. They describe registrations, not fuel economy or CO₂ emissions.