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Two sheets, one bench · Large Cars

Phantom Extended vs G80 AWD

Rolls-Royce Phantom Extended against Genesis G80 AWD, two test sheets laid side by side.

vs

Genesis G80 AWD

20.5
MPG · $2341/yr
More efficient

The gap, in fuel

$1,351a year between them

The Genesis G80 AWD is more efficient — 20.5 MPG against 13 for the Rolls-Royce Phantom Extended. Over 15,000 miles a year at $3.20 a gallon that is a saving of about $1351 a year, or $6754 over five years.

SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026

How this is worked out

  1. Start from the EPA combined figure for the model year — a laboratory test cycle run to a fixed procedure, not a road result. Where a year sold several engines or drivetrains, the trims are averaged and the trim count is printed beside the row so you can see how much averaging is behind it.
  2. Fix a pump price. This site keeps one reference price, $3.20 a US gallon, fixed JUL 2026 and printed next to every dollar figure it produces. It is an assumption with a date on it, not a quote — put your own price in.
  3. Fix an annual distance. Every annual figure on this site uses 15,000 miles a year, roughly the US average. A cost per year with no stated distance is not a number, it is a mood.
  4. Divide distance by economy for gallons, multiply by price for the year's fuel, divide price by economy for one mile. The per-kilometre line is that last figure divided by 1.609344 — the same money, in the unit most of the world drives in.
  5. Stop there. No depreciation, no tyres, no insurance, no servicing. This is the fuel line of the ledger and it is labelled as one; depreciation usually dwarfs everything on it.
gallons/yr = miles/yr ÷ MPG
fuel  $/yr = gallons/yr × $/gal
cost  $/mi = $/gal ÷ MPG
cost  $/km = cost $/mi ÷ 1.609344

The full method, the licence note, and what a test figure cannot tell you →

Both sheets, line for line

Rolls-Royce Phantom ExtendedGenesis G80 AWD
Combined economy 13 20.5
Best year on record 14 25
Worst year on record 13 18
Average across all years 13.8 20.8
Fuel per year 3692 2341
Gallons per year 1154 732
CO₂ g/mi 656 432
Model years tracked 6 11
ClassLarge CarsLarge Cars
Years2022–20272017–2027

Highlighted cells are the better of the two on that measure. Fuel costs at $3.20/gal over 15,000 miles.

SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026

Questions asked across the counter

Which is more fuel efficient, the Rolls-Royce Phantom Extended or the Genesis G80 AWD?

The Genesis G80 AWD is more efficient — 20.5 MPG against 13 for the Rolls-Royce Phantom Extended. Over 15,000 miles a year at $3.20 a gallon that is a saving of about $1351 a year, or $6754 over five years.

Which is cheaper to run, the Rolls-Royce Phantom Extended or the Genesis G80 AWD?

On fuel alone, the Genesis G80 AWD: $2341 a year against $3692 for the Rolls-Royce Phantom Extended, both at $3.20 a gallon over 15,000 miles — an assumption fixed JUL 2026. Fuel is the only line being compared: depreciation, insurance, tyres and servicing are not in it, and they routinely matter more than this gap.

Is the difference big enough to change the decision?

Across five years of that same driving the gap comes to about $6754. That is real money, and it is also roughly what one year of depreciation does to a new car — so treat it as one line in the ledger rather than the whole argument.

Both entries carry the full year-by-year history and the pump-price ledger. Estimates based on official test figures and average fuel prices. Real-world consumption varies with driving style, load, terrain and maintenance.

See all 10 sites in this family, with what each one answers

Published by

Amit Sharma

Auckland real-estate agent and marketer. Builds free, sourced data tools.