Fuel Costs: Luxury Gas Cars vs Performance EVs

The 2025 Porsche 911 Carrera burns through $10,341 in fuel over five years. The 2025 Porsche Taycan Turbo S — a car that out-accelerates it in every measurable way — spends $7,050 on electricity over the same period. That $3,291 gap is real, but it’s also almost entirely beside the point once you see what the Taycan costs everywhere else.

Key Numbers at a Glance

Sources: KBB Cost to Own (2025 model year data, accessed May 2026); MSRP figures from KBB and manufacturer pricing. Finluxy True Ownership Cost Score = 5-year TCO ÷ MSRP × 100. Tesla Model S fuel cost uses KBB electricity cost estimate at 15,000 miles/year. BMW 530i fuel figure from KBB 530i trim-specific data.

The Fuel Cost Calculation: What the Numbers Actually Say

Fuel — whether gasoline or electricity — is rarely the dominant cost in luxury car ownership. Across all five vehicles analyzed here, fuel accounts for between 6% and 13% of five-year TCO. It matters, but it doesn’t determine the outcome. What it does reveal is the baseline efficiency difference between internal combustion engines in this segment and their EV equivalents.

The EPA rates the 2025 BMW 5 Series 530i at 31 miles per gallon (MPG) combined, which is class-competitive for a mild-hybrid luxury sedan. The 2025 Mercedes-Benz E-Class E350 comes in at 27–28 MPG combined according to EPA figures reported by Edmunds. The 2025 Porsche 911 Carrera, a genuine performance car with a flat-six producing well over 370 horsepower, achieves just 21 MPG combined — a rating that translates directly into KBB’s $10,341 five-year fuel estimate, the highest of any vehicle in this comparison.

On the EV side, the 2025 Tesla Model S Plaid (19-inch wheels) carries an EPA combined rating of 104 miles per gallon equivalent (MPGe), and even the heavier, more powerful 2025 Porsche Taycan Turbo S is rated at 79 MPGe combined by the EPA. At the EIA’s July 2025 baseline of approximately $3.10 per gallon for regular gasoline and residential electricity averaging around 17.5 cents per kilowatt-hour (kWh) through mid-2025, these MPGe ratings translate into meaningfully lower per-mile energy costs — roughly 3.7 to 4.5 cents per mile for the EVs versus 9 to 14 cents per mile for the gas vehicles at typical driving rates.

But here is where the straightforward efficiency narrative runs into the data.

Sources: EPA combined ratings from fueleconomy.gov / driveclean.ca.gov (EPA data, 2025 model year); KBB 5-year fuel cost figures (accessed May 2026); Edmunds MPG data for E-Class E350. Annual fuel costs derived from KBB 5-year totals. Tesla Model S MPGe from EPA 2025 data (base Long Range model); Plaid-specific MPGe (19-inch wheels): 104 MPGe combined per EPA.

The Mercedes-Benz E-Class E350’s five-year fuel cost of $5,302 is the lowest figure in the entire comparison — lower than both EVs. That counterintuitive result comes down to the E350’s relatively efficient mild-hybrid 2.0-liter engine combined with KBB’s modeled fuel price trajectory, which incorporates the EIA’s projected decline in gasoline prices toward approximately $3.00 per gallon through 2026. The Taycan Turbo S edges out the Tesla Model S on electricity costs, but both EVs outspend the E-Class on fuel despite their efficiency advantage.

The Overlooked Cost: Insurance Eats the Fuel Savings

Every fuel-cost comparison in this segment understates a structural imbalance: insurance premiums at this tier routinely exceed annual fuel spend by a factor of two to ten. The 2025 Porsche 911 Carrera costs an estimated $19,460 to insure over five years per KBB data — nearly double its $10,341 fuel bill. The Taycan Turbo S carries $24,300 in five-year insurance costs, more than three times its fuel bill. The Tesla Model S base model runs $49,294 in total out-of-pocket expenses despite only $9,451 in electricity; its luxury car insurance cost contributes disproportionately to that total.

This is the figure that most fuel-economy coverage ignores entirely. Framing an EV choice around energy savings misses the structural reality: for a $95,000–$209,000 vehicle, fuel is a rounding error. Insurance, depreciation, and maintenance determine the actual cost spread between gas and electric in this price range.

Where Depreciation Makes or Breaks the Math

Depreciation — the loss in vehicle value from purchase to resale — is the single largest cost component for every vehicle analyzed here. Understanding how depreciation eats luxury car value year by year shapes the entire comparison.

The 2025 Porsche 911 Carrera loses $63,394 over five years on a base MSRP of $122,095 — roughly 52% of its sticker price. The 2025 Tesla Model S base drops $57,957 on an $81,630 MSRP, or about 71%. The Taycan Turbo S sheds $111,822 from its $209,000 starting price, a hit of 53.5%. These figures come from KBB’s cost-to-own methodology, which models projected residual values based on historical depreciation curves and segment dynamics. iSeeCars depreciation research puts the broader Taycan lineup at approximately 55% five-year depreciation, broadly consistent with KBB’s Turbo S figures given that higher-priced trims typically carry greater absolute dollar losses.

The 911 Carrera’s depreciation story is the most defensible in this group. At 52% over five years on a vehicle priced north of $122,000, it tracks better than both the Tesla Model S (71%) and the Taycan Turbo S (53.5% percentage-wise, but $111,822 in absolute dollars). Porsche’s retention of collector and driver demand historically supports this. The contrast with the Tesla Model S is stark: two vehicles in adjacent price tiers show a 19-percentage-point gap in five-year depreciation rate, and EV resale dynamics have not stabilized to the degree that pre-purchase projections can be taken at face value. For a deeper look at how the 911 stacks up in the investment context, see the Porsche vs Ferrari as an investment analysis.

Finluxy True Ownership Cost Score

The Finluxy True Ownership Cost Score expresses five-year TCO as a percentage of a vehicle’s MSRP. A score of 100% means the car costs exactly its sticker price to own and operate for five years after accounting for depreciation. A score above 100% means total five-year costs exceed the purchase price. Lower is better — it signals better value retention relative to what was paid at the window.

Sources: KBB Cost to Own (2025 model year, accessed May 2026); MSRP from KBB and manufacturer pricing. Formula: 5-year TCO ÷ MSRP × 100. Score below 100% indicates five-year costs fall below original sticker price.

The Taycan Turbo S produces the only sub-100% score in the group at 89.5% — meaning KBB’s model projects that the total cost of owning and operating the car for five years is less than its purchase price. That result is primarily a residual value story: KBB projects a $99,173 five-year residual on a $209,000 car, meaning the Taycan Turbo S retains nearly half its value. Whether that projection holds depends on EV market conditions through 2030, which remain volatile. But as modeled with current data, the Taycan Turbo S is the most cost-efficient vehicle in this comparison by a significant margin.

The 911 Carrera at 107.3% confirms what the Porsche resale market has long demonstrated: the Porsche 911 annual cost structure rewards owners who hold the car. Among gas cars, it clearly dominates on the Score. The BMW 530i’s 136.6% result reflects the arithmetic penalty of applying running costs to a relatively low MSRP base — its absolute TCO of $81,757 is lower than every other vehicle here, but the ratio is punishing because the denominator is small.

Gas vs EV: The Comparison That Actually Matters at This Price Point

The BMW 5 Series 530i and the Tesla Model S are not natural head-to-head rivals — the BMW starts at $59,875, the Tesla at $81,630 — but they occupy overlapping territory in the $80,000–$110,000 all-in purchase range for buyers who configure either vehicle. Placed side by side in the KBB framework, their five-year TCO figures are $81,757 and $107,251 respectively, a $25,494 gap that the Tesla’s fuel savings ($0 difference on fuel in this comparison — KBB assigns identical $9,451 fuel costs to both) do absolutely nothing to close. The gap is driven almost entirely by depreciation: $39,732 for the BMW versus $57,957 for the Tesla, a $18,225 difference over five years. For a deeper comparison of ownership economics in adjacent segments, the Audi A6 vs BMW 5 Series true cost comparison provides useful benchmarking.

The Porsche comparison is cleaner and more instructive. Two performance flagships, both from the same manufacturer’s performance lineage: the 911 Carrera at $122,095 MSRP and $131,014 in five-year TCO, versus the Taycan Turbo S at $209,000 MSRP and $187,060 in five-year TCO. The EV costs $87,000 more to buy and $56,000 less to own over five years, primarily because KBB’s residual projections favor the Taycan Turbo S. The Porsche 911 annual cost breakdown makes clear that insurance and maintenance — at $11,664 for maintenance alone over five years — are the 911’s most punishing non-depreciation line items.

Maintenance is where the EV advantage is most structurally durable. The Taycan Turbo S carries $3,439 in five-year maintenance costs versus the 911 Carrera’s $11,664. The Tesla Model S logs $3,269 in five-year maintenance against the BMW 530i’s $3,269 — an identical figure, which reflects that the cost-to-own model assigns similar servicing assumptions to both. For maintenance cost detail across the segment, see the analysis of how much luxury car maintenance really costs.

Sources: KBB Cost to Own (2025 model year data, accessed May 2026). Tesla Model S insurance figure not broken out in KBB trim-level data used; $107,251 TCO includes all components from KBB overall Model S data. Insurance for BMW 530i from KBB 530i trim-specific breakdown. KBB assumes 15,000 miles/year and standard financing terms.

The Insight Most Fuel-Cost Coverage Misses

The dominant framing in EV-versus-gas coverage is fuel savings as the primary financial argument. The data from this specific segment tells a different story: the Mercedes-Benz E-Class E350, a traditional luxury gas sedan, posts the lowest five-year fuel bill of any vehicle in this comparison at $5,302 — beating both EVs. That happens because KBB’s model prices the E350’s mild-hybrid efficiency (27–28 MPG combined, EPA) against a falling gasoline price forecast from the EIA, while electricity costs remain relatively flat. The result is a gas vehicle beating performance EVs on the fuel line item that is supposed to be electric cars’ strongest selling point.

The implication for $150k+ buyers is direct: fuel savings arguments don’t hold at this price tier when applied to performance EVs. The Taycan Turbo S’s $7,050 five-year energy cost is compelling in isolation, but it sits inside a $187,060 TCO figure where depreciation alone runs to $111,822. Selecting or rejecting a vehicle in this segment based on fuel costs is optimizing a variable that represents 3–8% of total ownership cost. For a full accounting of what goes into the luxury car ownership cost picture, the relevant levers are depreciation curves and insurance premiums — not fill-up frequency.

Context for $150k+ Households

At a household income of $150k+, none of the vehicles analyzed here is financially out of reach on an income basis. The relevant decision framework is different: which cost structure fits how you hold assets? For buyers who plan to own for three years and trade, the 911 Carrera’s historically flat depreciation curve and the Taycan Turbo S’s projected residual value both look defensible. For five-year holders, the Taycan Turbo S’s 89.5% Finluxy True Ownership Cost Score is the outlier — it’s the only vehicle here where holding costs over five years are projected to run below purchase price, driven by strong residual assumptions. That calculation, however, requires those residual values to hold, and the EV resale market in 2028–2030 remains genuinely uncertain.

The BMW 530i and Mercedes-Benz E-Class represent the opposite thesis: predictable, relatively modest TCO in absolute dollar terms with higher percentage cost scores against a lower MSRP base. Neither is optimized for resale — the 530i’s $39,732 depreciation hit is still the largest proportional value loss at this price tier. For buyers buying at the $60k–$85k luxury sedan level and comparing gas versus electric, the data from the BMW 5 Series true cost analysis and Mercedes-Benz E-Class five-year cost analysis show that the segment is tightly bunched on TCO — but spread considerably on what drives that cost. Gas buyers pay more in fuel and maintenance. EV buyers pay more in depreciation and insurance. At the luxury sedan tier, neither wins cleanly on total cost.

For buyers operating at the $120,000–$210,000 tier — where the 911 Carrera and Taycan Turbo S compete — the income-to-car-cost ratio matters more than the gas-versus-electric framing. The decision question is about residual risk, not fill-up costs. A household evaluating what income supports a $100k+ vehicle should be stress-testing the depreciation assumptions before the fuel math, and comparing buying versus leasing at these price points, where lease residuals can be locked in against current market projections. See also how ownership economics shift across segments in the luxury SUV versus luxury sedan cost comparison.