Naming
BMW naming explained: what do 320d, M340i, X5, and i4 mean?
Decode a BMW name piece by piece: the series, the number, the final letter, xDrive, the X and i ranges, the M3 vs M Sport difference, and codes like E46 or G20.
Updated in 2026
Direct answer
How do you read a BMW name?
In “320d”, the 3 is the 3 Series, the 20 is a power index (historically the 2.0-litre displacement), and the d means diesel. The name reads left to right: family, power level, fuel, then drivetrain and body style.
- Read the first character: it is the family (1 to 8, X, Z, i, or M).
- Read the next two digits: they are the power level within that family.
- Read the final letter: i for petrol, d for diesel, e for plug-in hybrid.
- Read the rest: xDrive, Touring, and Gran Coupé describe drivetrain and body.
Why these names look unreadable
A BMW name is not decorative: it is an address. Three characters place a car inside the range, and everything after that describes drivetrain and body. It is the clearest system on the market, on one condition: knowing where the original logic was abandoned.
Because it was. The rule most people know — the number equals the displacement — stopped being true in the early 2010s. Understanding a BMW name today mostly means knowing what the name no longer tells you.
“320d xDrive Touring” piece by piece
| Piece | What it means |
|---|---|
| 3 | The family: 3 Series, the mid-size saloon. Odd series (1, 3, 5, 7) form the classic line, even ones (2, 4, 6, 8) are their sportier counterparts. The 4 Series is the coupé 3 Series, the 2 comes from the 1, the 6 from the 5, the 8 from the 7. |
| 20 | The power level within the family. Historically the displacement in decilitres: 320 for 2.0 L, 325 for 2.5 L, 330 for 3.0 L. That link has been broken since the early 2010s: see below. |
| d | The energy: d for diesel, i for petrol, e for plug-in hybrid. |
| xDrive | All-wheel drive. Its opposite, sDrive, means rear-wheel drive — mostly seen on the X and Z ranges. |
| Touring | The body style: Touring for the estate, plus Coupé, Cabrio, Gran Coupé for the four-door coupé, and Gran Turismo for the raised hatchback. |
The families: what the first character says
| Letter or number | Family |
|---|---|
| 1 à 8 | Saloons, hatchbacks, and coupés, from smallest to most upmarket. |
| X | The SUVs, which BMW calls SAVs. X1 to X7, same size logic. Even X models (X2, X4, X6) are the sloping-roof versions of the odd ones. |
| Z | The two-seat roadsters: Z3, Z4, and the collectible Z8. |
| i | As a prefix, the electric range: i3, i4, i5, i7, iX. |
| M | As a standalone prefix (M2, M3, M5), cars engineered by the M division. Beware of look-alikes: see the trap below. |
Examples in photos
A few cars from the ScanRacer library, each illustrating one piece of the name:
Where the rule no longer holds
The number no longer gives the displacement. Since the early 2010s it ranks power, nothing else. A 318d and a 320d share the same 2.0 diesel; a 330i is a turbocharged 2.0 petrol while a 340i really is a 3.0. Two consecutive names can hide the same engine, and two distant numbers can too.
The letter “i” has two meanings in the same name. Originally it flagged fuel injection (Einspritzung), hence petrol: that is the i in 320i or M340i. As a prefix it now means electric: i4, i5, iX. An M340i burns petrol, an i4 does not — same character, two meanings, depending on where it sits.
The letter “e” changed meaning too. On a 1980s 325e it marked the eta engine, built for low consumption. On today's 330e it marks a plug-in hybrid. Same letter, forty years apart, no connection.
Some names follow nothing at all. The M3 stays the M3 whatever its engine, the XM has no number, and older models like the 2002 read the other way round: 02 series, two litres, two doors.
The suffixes worth knowing
| Mention | Meaning |
|---|---|
| i | Petrol (at the end of the name). |
| d | Diesel. |
| e | Plug-in hybrid on recent models. |
| xDrive | All-wheel drive. |
| sDrive | Rear-wheel drive, mostly on X and Z models. |
| Touring | Estate. |
| Gran Coupé | Four-door saloon with a coupé roofline. |
| CS / CSL | Lighter, sharper versions of M models. |
The trap: M3, M340i, and M Sport are not the same thing
This is the most common car-spotting mistake, and it comes from three different uses of the same letter.
An M3 or M5 — a standalone M followed by a number — is engineered by BMW M: specific engine, chassis, and widened track. An M340i or M240i belongs to the M Performance range: quicker than a 330i, but built on a standard car. And “M Sport” is only a trim pack: wheels, bumpers, seats, sometimes suspension, on an otherwise ordinary 320d.
In the field, three cues settle it: the visibly widened fenders and twin-stalk mirrors of the real M cars, the four exhaust tips, and the badge — a lone M plus the model, versus an M glued to the number.
Codes like E46, F30, G20: the name the car does not wear
A 3 Series stays a 3 Series for fifty years. To tell generations apart, enthusiasts use BMW's internal chassis code, which appears nowhere on the car but is in the technical documents and in every spotter conversation.
The codes follow the alphabet over time: E for older generations, F for the 2010s, G for current cars. Saying “an E46” rather than “a 2001 3 Series” is more precise and avoids mixing up close generations.
| Code | Generation |
|---|---|
| E30 | 1980s 3 Series, home of the first M3. |
| E36 / E46 | 1990s and 2000s 3 Series. |
| E90 / F30 / G20 | The following 3 Series generations, in chronological order. |
| E39 / E60 | 5 Series generations often cited for their M versions. |
To go further on dating a model, the dedicated guide covers the cues that separate two close generations.
Frequently asked questions
What does the d mean in BMW 320d?
The d means diesel. On the same 3 Series, an i marks petrol (320i) and an e a plug-in hybrid (330e).
Does a BMW's number match its displacement?
Not since the early 2010s. It now ranks power: a 318d and a 320d share the same 2.0 diesel, and a 330i is a 2.0 petrol, not a 3.0.
What is the difference between an M3 and an M340i?
The M3 is engineered by the BMW M division, with a specific engine and chassis. The M340i belongs to the M Performance range: quicker than a 330i, but built on a standard 3 Series. And “M Sport” is only a styling pack.
Why do the 4 Series and 3 Series look alike?
Because even series are derived from odd ones: the 4 Series is the coupé and convertible version of the 3 Series, just as the 2 comes from the 1 and the 6 from the 5.
What do E46 and G20 mean?
They are internal chassis codes naming a specific generation, here two generations of 3 Series. They do not appear on the car, but enthusiasts use them as references.
And if all you have is the car in front of you?
A badge can be removed, swapped, or added: it is one of the most common modifications. When the name is missing or looks wrong, the car itself remains — its silhouette, lights, and grille. That is where photo recognition takes over from decoding.