BMW 8 Series trim comparison
2025 BMW 8 Series 840i vs M850i xDrive
The 8 Series 840i starts at $101,400 while the M850i xDrive is $117,000. That $15,600 gap buys 8 meaningful differences.
This is a powertrain and drivetrain change. The M850i xDrive gets the 4.4L V8 Turbo and AWD, so the $15,600 is buying a different driving experience, not just nicer trim.
This is a real hardware fork, not just a trim-label shuffle. The 840i is enough if the 3.0L I6 Turbo with RWD already fits your routine; the M850i xDrive only earns the jump when the 4.4L V8 Turbo and AWD setup is the point of the upgrade.
If you are budgeting this move monthly, the jump from the 840i to the M850i xDrive is about $274/month on a 60-month loan at 6.5% APR with 10% down. That works out to roughly $16,440 more by the time interest is counted. If that different powertrain is not part of your real use case, the cheaper trim keeps more money in your pocket without changing the core experience you need.
Lock one trim, change the other side, and move through exact pair pages without resetting back to the full lineup every time.
Who notices the difference
The higher trim starts to make more sense when you are specifically shopping for the stronger powertrain, not just more trim content.
When both feel the same
The 840i and M850i xDrive are mechanically identical where it counts: the same 8-speed shiftable automatic transmission and identical wheelbase and body dimensions.
The upgrade math
You are paying $15,600 for 7 measurable differences, which works out to about $2,229 per change.
Key Differences at a Glance
This is the fast read: price, power, efficiency, and the feature flips most likely to change the answer.
Every Difference, Side by Side
This is the full read behind the quick decision signals above: the complete hardware, comfort, and equipment story. 8 specification differences, 0 shared.
Full Specification Comparison
Specifications reflect available data as of early 2025. Confirm details with an authorized dealer before purchasing.
| Spec | 840i | M850i xDrive |
|---|---|---|
| Pricing | ||
| MSRP | $101,400 | $117,000 |
| Powertrain | ||
| Engine | 3.0L I6 Turbo | 4.4L V8 Turbo |
| Horsepower | 335 hp | 523 hp |
| Torque | 369 lb-ft | 553 lb-ft |
| Transmission | 8-speed shiftable automatic | 8-speed shiftable automatic |
| Drivetrain | RWD | AWD |
| Fuel Economy | ||
| City MPG | 21 | 17 |
| Highway MPG | 29 | 24 |
| Combined MPG | 24 | 19 |
| Fuel Tank | 18.0 gal | 18.0 gal |
| Annual Fuel Cost (EPA) | $2,400/yr | $3,050/yr |
| Dimensions | ||
| Curb Weight | 4,156 lbs | 4,691 lbs |
| Wheelbase | 111.1" | 111.1" |
| Length | 191.2" | 191.2" |
| Width | 74.9" | 74.9" |
| Height | 53.0" | 53.0" |
| Warranty | ||
| Bumper-to-Bumper | 4yr/50k | 4yr/50k |
| Powertrain | 4yr/50k | 4yr/50k |
| Corrosion | 12yr/unlimited | 12yr/unlimited |
| Roadside Assistance | 4yr/unlimited | 4yr/unlimited |
Data sources: licensed third-party automotive data, EPA fueleconomy.gov, NHTSA, and official manufacturer materials. Values marked est. are estimated.
2025 BMW 8 Series 840i vs M850i xDrive Questions Shoppers Ask
Use this page for the direct trim answer, then zoom back out to the BMW 8 Series lineup, the BMW brand hub, the Sports Cars, the how to pick a trim guide, or our mid-trim value research when you need the bigger shopping path behind this one matchup.
How much more does the 2025 8 Series M850i xDrive cost than the 840i?
The M850i xDrive starts at $117,000 compared to $101,400 for the 840i. That is a $15,600 difference, or approximately $274/month more on a 60-month loan.
Do the 2025 BMW 8 Series 840i and M850i xDrive have the same engine?
No. The 840i uses a 3.0L I6 Turbo (335 hp, 369 lb-ft), while the M850i xDrive has the 4.4L V8 Turbo (523 hp, 553 lb-ft). That is 188 more horsepower. Both pair with the same 8-speed shiftable automatic.
Does the 2025 8 Series 840i come with AWD?
No. The 840i comes standard with RWD while the M850i xDrive has AWD. This affects traction, fuel economy, and curb weight.
What warranty does the 2025 BMW 8 Series come with?
All 2025 BMW 8 Series trims, including both the 840i and M850i xDrive, come with BMW's standard warranty: 4yr/50k bumper-to-bumper and 4yr/50k powertrain coverage. Warranty does not vary by trim level.
Is the 2025 BMW 8 Series M850i xDrive worth $15,600 more than the 840i?
The M850i xDrive changes both the engine and drivetrain for $15,600 more. That is a hardware upgrade, not just a feature bump.
Which 2025 BMW 8 Series trim gets better fuel economy, the 840i or the M850i xDrive?
The 840i is the more efficient of the two at 24 combined MPG, versus 19 for the other trim. That matters most if you are balancing running costs against the extra power, drivetrain, or comfort equipment tied to the pricier trim.
The Full Story Behind This Price Gap
Use the direct answer above for this exact matchup, then use these guides to understand whether you are really looking at a feature step-up, a package shuffle, or the point where the lineup starts changing in a meaningful way.
What $15,600 Gets You
The 8 Series M850i xDrive is a clear upgrade over the 840i. The $15,600 price increase gets you the 4.4L V8 Turbo engine (+188 hp) and AWD -- real functional changes, not just cosmetics.
840i vs. M850i xDrive: Day-to-Day
Engine is where these two diverge most: 3.0L I6 Turbo in the 840i, 4.4L V8 Turbo in the M850i xDrive. That means 188 more horsepower and 184 more lb-ft of torque. A significant jump that changes the driving experience. In return, expect about 5 fewer combined MPG. The M850i xDrive has AWD while the 840i has RWD. This affects traction, weight, and fuel economy.
Fuel Economy Comparison
The 8 Series 840i gets 5 more combined MPG. At $3.50/gallon and 12,000 miles/year, that saves roughly $461 per year or $2,305 over five years of ownership.
Summary
The 8 Series M850i xDrive costs $15,600 more than the 840i (about $274/month more on a 60-month loan). That buys 7 meaningful changes at $2,229 per change. Whether that trade-off is worth it depends on which features matter to your daily driving.
Trim-Matched Accessories
These add-ons are split by trim intent so the recommendations follow the actual use case, not just the same repeated product block.
BMW 8 Series 840i
Value-trim add-onsThese picks fit the 840i best when the goal is covering the daily-use gaps without paying up to the next trim.
BMW 8 Series M850i xDrive
Step-up trim add-onsThese picks suit the M850i xDrive when you want the accessories to match the nicer cabin, broader utility, or more premium use case.
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Specifications shown combine licensed third-party automotive data with official manufacturer, EPA, and NHTSA source material for the 2025 model year. Actual pricing, features, and availability may vary by region and dealer. Always confirm details with an authorized dealer before making a purchase decision. TrimAtlas is not affiliated with BMW or any dealership.
Page updated 2026-03-18. Verify equipment, pricing, and regional availability with the manufacturer or dealer.