Specification comparison of 2025 BMW M850i xDrive Convertible, 2026 Aston Martin DB12 Volante. The best value in each comparable row is labelled “Best”.
Power-to-weight ratioHigher is betterCalculated from peak power and curb weight — figures quoted against a different weight basis (e.g. dry or DIN) will differ.
243.5 hp/tCalculated
353.4 hp/t✓ BestCalculated
Acceleration
0–60 mphLower is betterRollout (1ft) handling differs between testers and manufacturers.
3.80 sManufacturer claim · BMW
3.60 s✓ BestManufacturer claim · Aston Martin
0–100 km/hLower is better
3.90 sManufacturer claim · BMW
3.70 s✓ BestManufacturer claim · Aston Martin
0–100 mph
8.30 sIndependent test · Car and Driver
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0–200 km/h
13.5 sIndependent test · auto motor und sport
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Braking
70–0 mph braking distance
151.0 ftIndependent test · Car and Driver
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Engine & Powertrain
Peak powerHigher is better
523 hpManufacturer claim · BMW
671 hp✓ BestManufacturer claim · Aston Martin
Peak torqueHigher is better
553 lb-ftManufacturer claim · BMW
590 lb-ft✓ BestManufacturer claim · Aston Martin
Engine displacement
4395.0 ccManufacturer claim · BMW
4000.0 ccManufacturer claim · Aston Martin
Cylinder count
8Manufacturer claim · BMW
8Manufacturer claim · Aston Martin
Engine layout
V8Manufacturer claim · BMW
V8Manufacturer claim · Aston Martin
Engine placement
FrontManufacturer claim · BMW
Dimensions
Length
191 inManufacturer claim · BMW
186 inManufacturer claim · Aston Martin
Width
75 inManufacturer claim · BMW
78 inManufacturer claim · Aston Martin
Height
53 inManufacturer claim · BMW
51 inManufacturer claim · Aston Martin
Wheelbase
111 inManufacturer claim · BMW
110 inManufacturer claim · Aston Martin
Ground clearance
5 inManufacturer claim · BMW
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Weight
Curb weightLower is better
4736 lbManufacturer claim · BMW
4184 lb✓ BestManufacturer claim · Aston Martin
Fuel Economy
Fuel economy (combined)Lower L/100km is better; higher mpg is better — direction is on the canonical L/100km.
19.0 mpgHomologation · US EPA
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Fuel economy (city)Lower L/100km is better; higher mpg is better — direction is on the canonical L/100km.
17.0 mpgHomologation · US EPA
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Fuel economy (highway)Lower L/100km is better; higher mpg is better — direction is on the canonical L/100km.
24.0 mpgHomologation · US EPA
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Fuel tank capacity
18.0 galManufacturer claim · BMW
20.6 galManufacturer claim · Aston Martin
Estimated range (combined)Estimated from tank capacity and quoted combined economy — not an instrumented range.
342 miCalculated
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Estimated range (highway)Estimated from tank capacity and quoted highway economy — not an instrumented range.
Practicality
Cargo volume
12 ft³Manufacturer claim · BMW
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Seats
4Manufacturer claim · BMW
4Manufacturer claim · Aston Martin
Pricing
Base price (as tested market)Demo prices only; not live FX.
$117,000Homologation · US EPA
$282,000Independent test · CarBuzz
Tires & Wheels
Front tire size
245/35R20 95Y XLManufacturer claim · BMW
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Rear tire size
275/30R20 97Y XLManufacturer claim · BMW
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Every figure is the car’s preferred, sourced value. “Best” marks the strongest value in a row, judged on the canonical measurement (so a winner is correct whichever unit system you view). Open a car to see each value’s source, original units, and alternates.
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