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BMW 3 Series vs Mercedes-Benz C-Class: fuel economy and fuel cost

In model year 2026 the BMW 3 Series is the cheaper of the two to fuel: about $2,630 a year for its lowest-cost configuration (330i Sedan, 31 MPG combined), against $2,770 for the Mercedes-Benz C-Class (C300, 29 MPG combined). That is $140 a year, or $700 over five years.

Both are classed as Small cars by the EPA. Costs assume 15,000 miles a year and the same fuel and electricity prices for both vehicles, using the EPA combined rating (55% city, 45% highway). Each figure is rounded to $10 and every difference is calculated from the rounded values.

The EPA is still publishing model year 2027 ratings, so this page compares model year 2026, the latest complete year.

Illustration: Small cars
  • Hybrid
  • Small cars

BMW 3 Series

Lowest fuel cost configuration

330i Sedan

31 MPG
Combined
28 MPG
City
35 MPG
Highway
Annual fuel cost
$2,630

$17.53 per 100 miles

15,000 mi/yr, same fuel prices

4 configurations in MY2026

Illustration: Small cars
  • Hybrid
  • Small cars

Mercedes-Benz C-Class

Lowest fuel cost configuration

C300

29 MPG
Combined
25 MPG
City
35 MPG
Highway
Annual fuel cost
$2,770

$18.47 per 100 miles

15,000 mi/yr, same fuel prices

3 configurations in MY2026

What the fuel costs

Annual fuel cost of the lowest-cost configuration

  • BMW 3 Series$2,630 a year · $17.53 per 100 mi
  • Mercedes-Benz C-Class$2,770 a year · $18.47 per 100 mi

Difference per year

$140

BMW 3 Series costs less to fuel

Over 5 years

$700

$140 a year × 5, 15,000 mi/yr, same fuel prices

Head to head, MY2026

BMW 3 Series and Mercedes-Benz C-Class compared on their lowest fuel cost configuration
Measure BMW 3 Series Mercedes-Benz C-Class
Lowest-cost configuration 330i SedanC300
Powertrain HybridHybrid
Combined rating 31 MPG (better)29 MPG
City rating 28 MPG (better)25 MPG
Highway rating 35 MPG35 MPG
Annual fuel cost $2,630/yr (better)$2,770/yr
Cost per 100 miles $17.53 (better)$18.47
Annual cost range, all configurations $2,630–$2,790$2,770–$3,690
Configurations in MY2026 43
EPA class Small carsSmall cars

Best configuration by powertrain

Lowest-cost configuration of each powertrain, BMW 3 Series and Mercedes-Benz C-Class
Powertrain BMW 3 Series Mercedes-Benz C-Class
Hybrid 31 MPG · $2,630/yr 330i Sedan 29 MPG · $2,770/yr C300

Each cell shows the combined rating and the annual fuel cost of the lowest-cost configuration with that powertrain.

Where each one comes out ahead

Generated from the numbers above, comparing the lowest fuel cost configurations. No subjective judgements.

BMW 3 Series

  • Lower annual fuel cost: $2,630 vs $2,770
  • Higher combined rating: 31 MPG vs 29 MPG
  • Higher city rating: 28 MPG vs 25 MPG

Mercedes-Benz C-Class

Not ahead on any measure listed here.

Level on: highway rating (35 MPG)

Year by year

Combined rating and annual fuel cost by model year, BMW 3 Series and Mercedes-Benz C-Class
Model year BMW 3 Series Mercedes-Benz C-Class
CombinedPer yearCombinedPer year
2026 29–31 MPG $2,630–$2,790 22–29 MPG $2,770–$3,690
2025 29–31 MPG $2,630–$2,790 20–29 MPG $2,760–$3,690
2024 26–29 MPG $2,170–$3,100 23–30 MPG $2,700–$3,510
2023 26–29 MPG $2,170–$3,090 19–29 MPG $2,790–$4,190
2022 25–30 MPG $2,050–$3,080 22–29 MPG $2,770–$3,680
2021 25–30 MPG $2,050–$2,840 20–27 MPG $2,930–$4,080
2020 28–30 MPG $2,710–$2,840 20–28 MPG $2,870–$4,080
2019 23–30 MPG $2,710–$3,480 20–27 MPG $3,000–$4,080
2018 23–36 MPG $2,160–$3,550 19–30 MPG $2,380–$4,250
2017 23–36 MPG $2,160–$3,550 19–30 MPG $2,380–$4,250
2016 23–35 MPG $1,990–$3,520 20–30 MPG $2,380–$3,980
2015 23–36 MPG $2,640–$3,560 15–28 MPG $2,890–$5,190
2014 23–36 MPG $2,640–$3,540 15–25 MPG $3,220–$5,190
2013 19–28 MPG $2,870–$4,170 15–25 MPG $3,220–$5,200
2012 19–27 MPG $3,010–$4,150 15–25 MPG $3,270–$5,200
2011 19–27 MPG $3,500–$4,160 15–21 MPG $3,850–$5,350
2010 19–27 MPG $3,500–$4,230 15–21 MPG $3,830–$5,360
2009 19–27 MPG $3,500–$4,230 15–21 MPG $3,830–$5,360
2008 19–22 MPG $3,650–$4,230 15–21 MPG $3,830–$5,360
2007 20–22 MPG $3,650–$4,020 19–22 MPG $3,650–$4,230
2006 19–21 MPG $3,830–$4,230 17–22 MPG $3,650–$4,730
2005 19–22 MPG $3,650–$4,230 16–24 MPG $3,350–$5,020
2004 19–22 MPG $3,650–$4,230 16–23 MPG $3,490–$5,020
2003 19–22 MPG $3,650–$4,230 17–24 MPG $3,350–$4,730
2002 18–22 MPG $3,650–$4,460 17–21 MPG $3,830–$4,730
2001 18–21 MPG $3,830–$4,460 19–20 MPG $4,020–$4,230
2000 18–21 MPG $3,830–$4,460 18–22 MPG $3,650–$4,460

Earlier model years are costed with today's fuel prices, so the table shows how each model's efficiency changed, not what fuel cost at the time. Ranges cover every configuration of that model year.

Frequently asked questions

Which is cheaper to fuel, the BMW 3 Series or the Mercedes-Benz C-Class?

The BMW 3 Series is cheaper: about $2,630 a year against $2,770 for the Mercedes-Benz C-Class, a difference of $140 a year. That compares the lowest-cost configuration of each in model year 2026 at 15,000 miles a year with the same fuel prices.

How much would the BMW 3 Series save over five years?

About $700 ($140 a year for five years), assuming 15,000 miles a year and the same fuel prices. Your total depends on how much you drive and on local prices; see fuel cost by state.

Which has the better fuel economy rating, the BMW 3 Series or the Mercedes-Benz C-Class?

The BMW 3 Series is rated 31 MPG combined against 29 MPG for the Mercedes-Benz C-Class. City: 28 MPG vs 25 MPG. Highway: 35 MPG vs 35 MPG. These are the EPA ratings of each model's lowest-cost configuration.

How is the annual fuel cost calculated?

Distance of 15,000 miles a year at the EPA combined rating (55% city, 45% highway). Gasoline is priced at $4.36/gal (EIA U.S. average for regular, Sep 2026) and electricity at 18.3¢/kWh (EIA U.S. residential average, Jul 2026); premium and diesel configurations use their own EIA prices. Each result is rounded to $10, and differences are calculated from the rounded figures.

Are the BMW 3 Series and the Mercedes-Benz C-Class in the same class?

Yes. The EPA classes both as Small cars.

Explore these cars

More comparisons

EPA ratings: fueleconomy.gov file of Sep 29, 2026 · Prices: EIA regular gasoline, U.S. avg, Sep 2026 ($4.36/gal); residential electricity, U.S. avg, Jul 2026 (18.3¢/kWh) · 15,000 mi/yr, 55% city, same prices for both vehicles