BMW 840i vs Mercedes-Benz SL450
Side-by-side comparison from manufacturer specifications, NHTSA safety data, and live dealer listings.
Vehicles
Vehicles
2020 Mercedes-Benz SL450
Overview
| Spec | BMW 840i840i | Mercedes-Benz SL450SL 450 |
|---|---|---|
| Selected trim | 840i | SL 450 |
| Body style | Sedan | Convertible |
| Drivetrain | rear wheel drive | rear wheel drive |
| Fuel type | premium unleaded (recommended) | premium unleaded (required) |
| Transmission | 8-speed shiftable automatic | 9-speed shiftable automatic |
| Engine type | gas | gas |
| Model year | 2026 | 2020 |
Pricing & market
| Spec | BMW 840i840i | Mercedes-Benz SL450SL 450 |
|---|---|---|
| MSRP | $94,500 | $91,000 (best) |
| For sale now | 0 | 0 |
Fuel economy & range
| Spec | BMW 840i840i | Mercedes-Benz SL450SL 450 |
|---|---|---|
| Combined MPG | 24 MPG (best) | 22 MPG |
| City MPG | 21 MPG (best) | 20 MPG |
| Highway MPG | 29 MPG (best) | 28 MPG |
| Fuel tank | 18 gal | 19.8 gal (best) |
Performance
| Spec | BMW 840i840i | Mercedes-Benz SL450SL 450 |
|---|---|---|
| Horsepower | 335 hp | 362 hp (best) |
| Torque | 369 lb-ft | 369 lb-ft |
| Engine size | 3 L | 3 L |
| Cylinders | I6 | V6 |
Size & capability
| Spec | BMW 840i840i | Mercedes-Benz SL450SL 450 |
|---|---|---|
| Seating | 5 seats (best) | 2 seats |
| Doors | 4 (best) | 2 |
| Cargo volume | 15.5 cu ft (best) | 13.5 cu ft |
| Payload | 1,003 lbs (best) | — |
| Curb weight | 4,180 lbs | 3,825 lbs (best) |
| Ground clearance | 4.8 in (best) | 3.7 in |
| Wheelbase | 119 in (best) | 101.8 in |
| Length | 200.3 in (best) | 182.3 in |
| Width | 76.1 in (best) | 73.9 in |
| Height | 55.4 in (best) | 51.2 in |
Safety & recalls
| Spec | BMW 840i840i | Mercedes-Benz SL450SL 450 |
|---|---|---|
| Open recalls (YMM scope) | 1 | None reported (best) |
Highlighted values indicate the better figure for that spec when a clear winner exists. Specs reflect the selected trim for each vehicle. Drag a vehicle header to reorder columns. MSRP and specifications are manufacturer data; listing prices and inventory come from live dealer listings. Safety ratings are from NHTSA.
Trim overview
All available trims with MSRP. The trim selected above is highlighted; comparison specs use that selection.
| Trim | BMW 840i | Mercedes-Benz SL450 |
|---|---|---|
| 1 | 840i $94,500 MSRP(Currently comparing) | SL 450 $91,000 MSRP(Currently comparing) |
| 2 | 840i $94,500 MSRP | — |
| 3 | 840i $104,500 MSRP | — |
BMW 840i vs Mercedes-Benz SL450 FAQ
- Which is better: 2026 BMW 840i or 2020 Mercedes-Benz SL450?
- It depends on priorities. OpenDealer compares 2026 BMW 840i vs 2020 Mercedes-Benz SL450 on MSRP, fuel economy, horsepower, seating, towing, NHTSA safety ratings, and live market prices so you can weigh the tradeoffs.
- Which costs less: 2026 BMW 840i or 2020 Mercedes-Benz SL450?
- Based on starting MSRP, the 2020 Mercedes-Benz SL450 starts lower at $91,000.
- Which has better startingMsrp: 2026 BMW 840i or 2020 Mercedes-Benz SL450?
- The 2020 Mercedes-Benz SL450 leads on startingMsrp in this comparison (91,000).
- Which has better combinedMpg: 2026 BMW 840i or 2020 Mercedes-Benz SL450?
- The 2026 BMW 840i leads on combinedMpg in this comparison (24).
- Which has better horsepower: 2026 BMW 840i or 2020 Mercedes-Benz SL450?
- The 2020 Mercedes-Benz SL450 leads on horsepower in this comparison (362).
- Which has better seats: 2026 BMW 840i or 2020 Mercedes-Benz SL450?
- The 2026 BMW 840i leads on seats in this comparison (5).