3 Series Research for Northern California
2026 BMW 3 Series vs 4 Series
Same engines, same platform, different shapes. The 3 Series is a sedan. The 4 Series is a coupe, a convertible, and a four-door liftback. Body style decides this one.
The 2026 BMW 3 Series and 4 Series share engines, a platform, and most of their engineering. What separates them is the body. The 3 Series is a four-door sedan. The 4 Series comes three ways: a two-door Coupe, a two-door Convertible, and the four-door Gran Coupe, a liftback with a sloping roofline. Because the Gran Coupe is the only 4 Series with four doors, it is the fair like-for-like comparison against the 3 Series sedan, and it is where most of this page focuses.
At BMW of Napa Valley, we sell both, so nothing here is an argument for one over the other. The engines are identical: the 330i and 430i both make 255 horsepower, and the M340i and M440i both make 386 horsepower. Choose the shape that fits your life. We serve Solano County and Northern California, from Vacaville and Vallejo to American Canyon, right off I-80.
The 3 Series sedan is shown. Ask our team to see current 4 Series Coupe, Convertible, and Gran Coupe photography.
The Sedan
2026 BMW 3 Series Overview
The 3 Series is a conventional four-door sedan with a trunk. The 330i uses a 2.0L TwinPower Turbo 4-cylinder making 255 horsepower and 295 lb-ft; the M340i uses a 3.0L M TwinPower Turbo inline-six making 386 horsepower and 398 lb-ft. Both carry 48-volt mild-hybrid assistance and an 8-speed automatic. Rear-wheel drive is standard, xDrive is $2,000. Pricing starts at $48,000 MSRP. The rear-wheel-drive 330i is EPA-estimated at 31 MPG combined, the trunk holds 16.9 cubic feet, and the M340i xDrive reaches 60 mph in about 4.1 seconds.
The Three Bodies
2026 BMW 4 Series Overview
The 4 Series takes the same two engines and wraps them in three bodies. The Coupe is a two-door with a fixed roof. The Convertible replaces that roof with a power-folding top. The Gran Coupe has four doors, a swept roofline, and a rear liftback instead of a trunk lid.
Engines carry over exactly: the 430i makes 255 horsepower and 295 lb-ft, the M440i makes 386 horsepower and 398 lb-ft, both with 48-volt mild-hybrid assistance and an 8-speed automatic. Rear-wheel drive is standard and xDrive is available. The Gran Coupe starts at $51,200 MSRP for the 430i. Coupe and Convertible pricing varies by body and equipment; ask our team for current figures.
Under the Hood
Powertrain Comparison
There is no engine argument here. The four-cylinder and six-cylinder are the same units in both cars. What changes is weight, roofline, and gearing, and those show up at the stopwatch.
| Measure | 3 Series Sedan | 4 Series Gran Coupe |
|---|---|---|
| Four-cylinder | 330i: 255 horsepower, 295 lb-ft | 430i: 255 horsepower, 295 lb-ft |
| Six-cylinder | M340i: 386 horsepower, 398 lb-ft | M440i: 386 horsepower, 398 lb-ft |
| Transmission | 8-speed automatic | 8-speed automatic |
| Drivetrain | Rear-wheel drive standard; xDrive $2,000 | Rear-wheel drive standard; xDrive available |
| Six-cylinder 0-60 mph, all-wheel drive | M340i xDrive: about 4.1 seconds | M440i xDrive Gran Coupe: 4.3 seconds |
| EPA combined, four-cylinder | 330i: 31 MPG combined, EPA-estimated | 430i: 29 to 30 MPG combined, EPA-estimated |
Two details worth noticing. The sedan is the quickest of the family with the six-cylinder: the M340i xDrive reaches 60 mph in about 4.1 seconds, ahead of the M440i xDrive Gran Coupe's 4.3 seconds and the M440i xDrive Coupe's 4.2. And the 330i's 31 MPG combined edges the 430i Gran Coupe's 29 to 30, because the Gran Coupe's body carries a small efficiency penalty.
Doors, Roof, and Cargo
Practicality and Space Comparison
Behind the rear seats the two are nearly identical: 16.9 cubic feet in the 3 Series trunk against 16.6 in the Gran Coupe. Fold the seats and the picture changes completely. The Gran Coupe's liftback opens to 45.6 cubic feet through a wide hatch. The sedan's rear seats fold too, but the pass-through opening is narrower because of the rear window.
| Measure | 3 Series Sedan | 4 Series Gran Coupe |
|---|---|---|
| Doors | Four | Four |
| Cargo opening | Trunk lid | Rear liftback hatch |
| Cargo behind rear seats | 16.9 cubic feet | 16.6 cubic feet |
| Cargo with rear seats folded | Folds, but through a narrower opening | 45.6 cubic feet through a wide hatch |
| Rear-seat space | More usable; upright roofline | Slightly tighter under the sloping roof |
| Other bodies | Sedan only | Also offered as a Coupe and a Convertible |
The two-door bodies are a different proposition. The Coupe and Convertible seat four rather than five, and both carry noticeably less cargo than either four-door. The Convertible trades trunk space for a folding roof, and less still with the top stowed. If you want an open car, the 4 Series is the only one of these two that offers it.
The Money
Pricing and Value
Every figure below excludes destination, so the comparison is direct. Matching engine for engine, the Gran Coupe carries a consistent premium: $3,200 on the four-cylinder and $2,800 on the six.
| Build | Power | Starting MSRP (excludes destination) |
|---|---|---|
| BMW 330i Sedan | 255 horsepower | $48,000 MSRP |
| BMW 430i Gran Coupe | 255 horsepower | $51,200 MSRP |
| BMW M340i Sedan | 386 horsepower | $62,300 MSRP |
| BMW M440i Gran Coupe | 386 horsepower | $65,100 MSRP |
| BMW M440i xDrive Gran Coupe | 386 horsepower | $67,100 MSRP |
MSRP excludes destination, tax, title, license, and dealer fees. Coupe and Convertible pricing is not shown because published figures vary by body and source; contact the dealership for current pricing. Pricing can change; confirm with the dealership.
Both cars carry the same 4-year/50,000-mile basic warranty. Full detail on the sedan lineup is on our 3 Series trims page.
The Sedan Case
Where the 3 Series Wins
1. A more usable back seat. The sedan's upright roofline gives rear passengers more room. The Gran Coupe's sloping roof trades some of that away for its shape.
2. Slightly better fuel economy. The rear-wheel-drive 330i is EPA-estimated at 31 MPG combined against the 430i Gran Coupe's 29 to 30.
3. The quickest six-cylinder of the family. The M340i xDrive reaches 60 mph in about 4.1 seconds, ahead of the M440i xDrive Gran Coupe at 4.3 seconds and the M440i xDrive Coupe at 4.2.
4. A lower price for the same engine. $48,000 MSRP against $51,200 MSRP for the identical 255-horsepower four-cylinder, and $62,300 against $65,100 for the identical six.
The 4 Series Case
Where the 4 Series Wins
1. A liftback that swallows real cargo. Fold the Gran Coupe's rear seats and you get 45.6 cubic feet through a wide hatch opening. A sedan trunk cannot do that, whatever its stated volume.
2. Two doors, if that is what you want. The Coupe exists and the 3 Series has no two-door equivalent. Nothing in the sedan lineup replaces the proportions of a coupe.
3. A convertible. If you want the roof to disappear, this is the only one of the two that offers it. That is not a specification; it is the whole reason some people buy the car.
4. The shape. The Gran Coupe's swept roofline and frameless doors give it a presence the sedan does not have, with four doors and nearly the same trunk. Some buyers want the sedan's practicality in a body that looks like a coupe. That car exists, and it is this one.
Buyer Guide
Which Should You Choose?
Mechanically these are the same car. Buy the body you want to look at and live with.
| If You | Choose | Why |
|---|---|---|
| Carry adults in the back regularly | 3 Series | The upright roofline gives rear passengers more room. |
| Haul bikes, boxes, or awkward shapes | 4 Series Gran Coupe | 45.6 cubic feet with the seats folded, through a liftback hatch. |
| Want the quickest six-cylinder | 3 Series M340i xDrive | About 4.1 seconds to 60, quicker than the M440i in either body. |
| Want two doors or an open roof | 4 Series Coupe or Convertible | The 3 Series has no two-door or convertible body. |
| Want coupe styling with four doors | 4 Series Gran Coupe | The swept roofline and hatch, with rear doors and nearly the same trunk. |
| Want a classic sports sedan | 3 Series | It is the shape this segment was built around, at a lower price for the same engine. |
Because the engines are identical, a test drive tells you less about performance than about visibility, doorway height, and how the back seat feels with your family in it. Drive both. Compare the sedan's full specification on our 3 Series specifications page, or see how the sedan stacks up against the Audi A5, which is the Gran Coupe's closest outside rival.
Decide for Yourself
Drive Both in Fairfield
Our selection runs deepest in the 330i xDrive, and we typically carry the M340i. 4 Series availability varies by body style, so call ahead if you want to sit in a Gran Coupe or drop the top on a Convertible the same day. Drivers across Northern California make the trip to compare them side by side. Call (707) 402-1500 or contact our team.
Answers
3 Series vs 4 Series FAQs
What is the difference between the BMW 3 Series and 4 Series?
They share engines and a platform. The 3 Series is a four-door sedan. The 4 Series is offered as a two-door Coupe, a two-door Convertible, and the four-door Gran Coupe, which has a swept roofline and a rear liftback instead of a trunk lid.
Is the 4 Series faster than the 3 Series?
No. The engines are identical: the 330i and 430i both make 255 horsepower, and the M340i and M440i both make 386 horsepower. The M340i xDrive sedan reaches 60 mph in about 4.1 seconds, quicker than the M440i xDrive Gran Coupe at 4.3 seconds and the M440i xDrive Coupe at 4.2 seconds.
How much more does the 4 Series cost?
Comparing the same engine, the 430i Gran Coupe starts at $51,200 MSRP against the 330i's $48,000 MSRP, a difference of $3,200. The M440i Gran Coupe starts at $65,100 MSRP against the M340i's $62,300 MSRP, a difference of $2,800. Both figures exclude destination.
Which has more cargo space?
Behind the rear seats they are nearly equal: 16.9 cubic feet in the 3 Series trunk and 16.6 in the 4 Series Gran Coupe. With the rear seats folded, the Gran Coupe's liftback opens to 45.6 cubic feet through a wide hatch, while the sedan folds through a narrower opening.
Does the 3 Series come as a coupe or convertible?
No. The 3 Series is offered only as a four-door sedan. If you want a two-door coupe or a convertible with the same engines, that is the 4 Series Coupe or 4 Series Convertible.
Sedan, Coupe, or Convertible
BMW of Napa Valley, 2399 Auto Mall Pkwy, Fairfield, CA. Call (707) 402-1500 or start online.