GMC Sierra C15 2WD
What it costs to keep fuelled
$2,581a year, fuel only
The 2018 GMC Sierra C15 2WD is EPA-rated at 18.6 MPG combined (16.2 city / 22.6 highway). Over 15,000 miles a year that is about 806 gallons, $2581 a year in fuel, or $0.172 per mile at $3.20/gal.
Across its full 2007–2018 run it averages 17.2 MPG, improving by 2.6 MPG over 12 model years.
The band is how far one gallon carries it: 18.6 of the 60 MPG this scale runs to. The square tick is the standard pickup trucks 2wd average, 18.7.
- Fuel, per year
- $2,581 at 15,000 mi
- Per mile
- $0.172
- Per kilometre
- $0.107
- Gallons burned/yr
- 806
1 mile = 1.609344 km · fuel at $3.20/gal, fixed JUL 2026
Test figure — not a road resultSOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
How this is worked out
- 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.
- 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.
- 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.
- 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.
- 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 →
Re-run the ledger at another pump price
Every line above rests on one pump price. Here is the same entry re-costed at six others, because the price is the part that changes while the test sheet stays put.
| Fuel price | Per mile | 10,000 mi/yr | 15,000 mi/yr | 20,000 mi/yr |
|---|---|---|---|---|
| $2.50/gal | $0.134 | $1344 | $2016 | $2688 |
| $3.00/gal | $0.161 | $1613 | $2419 | $3226 |
| $3.20/gal | $0.172 | $1720 | $2581 | $3441 |
| $3.50/gal | $0.188 | $1882 | $2823 | $3763 |
| $4.00/gal | $0.215 | $2151 | $3226 | $4301 |
| $4.50/gal | $0.242 | $2419 | $3629 | $4839 |
| $5.00/gal | $0.269 | $2688 | $4032 | $5376 |
SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
The whole service history, sheet by sheet
12 model years on file. Read down the combined column: a nameplate that got heavier shows it here long before any brochure admits it.
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 2018 | 18.6 MPG | 16.2 | 22.6 | $3540 | 482 | 5 |
| 2017 | 18.6 MPG | 16.2 | 22.6 | $3360 | 484 | 5 |
| 2016 | 18.6 MPG | 16.2 | 22.4 | $3360 | 483 | 5 |
| 2015 | 18.8 MPG | 16.3 | 22.8 | $3338 | 480 | 4 |
| 2014 | 18.7 MPG | 16.3 | 22.3 | $3350 | 485 | 3 |
| 2013 | 16 MPG | 14.3 | 19.5 | $3913 | 559 | 4 |
| 2012 | 16 MPG | 14.3 | 19.5 | $3913 | 559 | 4 |
| 2011 | 16 MPG | 14 | 19.5 | $3913 | 559 | 4 |
| 2010 | 16.3 MPG | 14.3 | 19.8 | $3838 | 548 | 4 |
| 2009 | 16 MPG | 14 | 19.6 | $3900 | 556 | 8 |
| 2008 | 16.2 MPG | 14 | 19.3 | $4025 | 551 | 6 |
| 2007 | 16 MPG | 13.8 | 19.2 | $4067 | 557 | 6 |
Where a model year offered several engines or drivetrains, the figure is the average across all EPA-tested trims that year — the trim count is shown so you can see how much averaging is involved.
SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
Marked against the rest of the standard pickup trucks 2wd bay
Among the 29 standard pickup trucks 2wd models tracked here, the GMC Sierra C15 2WD ranks 14 on current figures, against a class average of 18.7 MPG — the square tick on the gauge above.
Closest more-efficient alternatives in the same class: Ford Ranger Pickup 2WD (19.8), Chevrolet Silverado 15 Hybrid 2WD (20), Ford F150 Pickup 2WD (20), Ford F150 Pickup 2WD FFV (20), GMC Sierra 15 Hybrid 2WD (20).
Tailpipe CO₂ is rated at 482 grams per mile, which works out to roughly 7.2 tonnes a year at 15,000 miles.
Questions asked across the counter
What MPG does the GMC Sierra C15 2WD get?
The 2018 GMC Sierra C15 2WD is rated at 18.6 MPG combined by the EPA — 16.2 city and 22.6 highway. Across all 12 model years in the database it averages 17.2 MPG, ranging from 14 to 20 depending on year and trim.
How much does a GMC Sierra C15 2WD cost in fuel per year?
At 18.6 MPG and 15,000 miles a year, it burns about 806 gallons — roughly $2581 a year with fuel at $3.20 a gallon, or $0.172 per mile. The EPA's own published annual figure for the 2018 model is $3540.
Has the GMC Sierra C15 2WD become more efficient over time?
Yes. It has gone from 16 MPG in 2007 to 18.6 in 2018 — an improvement of 2.6 MPG, or 16% across 12 model years.
Is the GMC Sierra C15 2WD efficient for its class?
It ranks 14 of 29 in the Standard Pickup Trucks 2WD class on current figures, against a class average of 18.7 MPG. That is 0.1 worse than typical for the class.
Pull another logbook off the same shelf
Same class, nearest economy first — the ones a buyer is genuinely choosing between.
SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
Cost per mile, per kilometre and per year are computed at a reference price of $3.20 a gallon over 15,000 miles, fixed JUL 2026 — set your own pump price. Estimates based on official test figures and average fuel prices. Real-world consumption varies with driving style, load, terrain and maintenance.
