The best fuel efficient used cars are compact petrol models such as the Honda Civic and Hyundai Elantra, plus used electric cars rated in MPGe. Check the EPA rating for the exact model year, then confirm real MPG on a test drive.
This page ranks by tested economy and ownership risk rather than by brand reputation. If you are weighing a plug-in instead, our electric vehicles guide covers that choice in more depth.
Why rated MPG and real MPG differ
A used car’s window-sticker rating is a standardised estimate, not a promise. The figures on fueleconomy.gov come from a site administered by Oak Ridge National Laboratory for the U.S. Department of Energy and the U.S. EPA, which makes it the right first stop for any model-year lookup. Some of its pages are labelled as driver estimates, so they reflect what owners report as well as the lab rating.
Speed is the main reason results move. Car and Driver notes that the EPA highway test averages 48.3 mph. The magazine’s own real-world test is a 200-mile loop of I-94 at a GPS-verified 75 mph, mostly on cruise control. Two cars can rank differently depending on which test you read, so judge a used car against its own model-year rating and against the kind of driving you do.
The practical result is that a rating is the baseline and your own commute decides the outcome. If most of your miles are motorway miles at higher speeds, give more weight to real-world highway tests than to the combined label figure. If you mostly drive in town, city ratings matter more.
Used models at a glance
The table below combines tested compacts and used electric cars so you can see how each is rated and what that means for a shortlist. Petrol figures are in mpg; electric figures are in MPGe, so compare each group within itself rather than reading EV numbers as petrol MPG.
| Model and year | Figures | Planning use |
|---|---|---|
| 2017 Honda Civic Si sedan | 42 mpg real-world highway; EPA highway estimate 38 mpg | Beats its label on a steady motorway run, so a good fit for long commutes. |
| 2017 Hyundai Elantra Eco | 43 mpg real-world highway; EPA highway estimate 40 mpg | Strongest petrol result here against its own rating; look for the Eco trim. |
| 2017 Hyundai Elantra Limited | 42 mpg in the same highway test | A well-equipped trim that gives up very little against the Eco. |
| 2017 Hyundai Ioniq Electric | 136 MPGe combined; 150 city / 122 highway | Suits mainly urban driving where the city rating applies. |
| 2021 Tesla Model 3 Standard Range Plus RWD | 142 MPGe combined; 150 city / 133 highway | Better highway rating than the Ioniq; suits mixed driving with home charging. |
Petrol figures are from Car and Driver’s real-world highway test, and electric ratings are from the EPA-backed fueleconomy.gov Top Ten list.
Petrol compacts: Civic and Elantra
Ordinary petrol compacts are the simplest route to low fuel bills on a used-car budget, because they need no battery checks and no charging set-up. Two names stand out in the supplied testing: the Honda Civic and the Hyundai Elantra.
Honda Civic
The 2017 Honda Civic Si sedan returned 42 mpg in Car and Driver’s real-world highway test, against an EPA highway estimate of 38 mpg. That makes it a car whose steady-speed economy holds up well. Treat it as a trim-specific data point, though: the Si is a sportier version, so confirm the rating for the exact Civic you are viewing on fueleconomy.gov rather than assuming every Civic matches it. It suits a buyer who wants a familiar compact and does a lot of motorway driving.
Hyundai Elantra
The Elantra is the clearest example of a car beating its label. The 2017 Elantra Eco is rated at 40 mpg on the highway by the EPA, and it produced 43 mpg in Car and Driver’s test. The 2017 Elantra Limited earned 42 mpg in the same test, so trim choice matters a little but not dramatically. If two cars are otherwise equal in condition and price, the Eco is the better fuel-economy bet. If the Limited has the better service history or equipment you want, its result is close enough that condition should decide.
Used electric cars as a fuel-saving option
A used EV can cut fuel spending sharply, but it only works if you can charge conveniently. The EPA list shows 2017 Hyundai Ioniq Electric at 136 MPGe combined and 2021 Tesla Model 3 Standard Range Plus RWD at 142 MPGe combined. For context, the highest combined EV rating on the same list is 146 MPGe, for a new 2027 Lucid Air Pure RWD, so these used cars sit in the same top tier.
The city and highway splits are the useful part. The Ioniq rates 150 in the city but 122 on the highway, a wider gap than the Model 3’s 150 city and 133 highway. If your driving is mostly short urban trips, either works well. If you regularly cover long motorway distances, the Model 3’s stronger highway rating is the better match.
Before committing, read how charging time fits your routine in our guide on How Long Does It Really Take To Charge An Electric Car? Practical Times, Examples, And Faster Charging Tips (2026) – Fixourfuel. A cheap-to-run EV that cannot be charged where you park is a poor buy.
Hybrids, battery risk and total ownership cost
Hybrids sit between petrol and electric cars, and they carry one risk the petrol compacts do not: the condition of the hybrid battery. A hybrid with strong economy on paper loses its advantage if the battery is tired, so treat battery condition as part of the price you are paying, not an afterthought. Ask an independent mechanic or a hybrid-capable specialist to assess it before you agree a price, and walk away if the seller will not allow an inspection.
For specific hybrid models and how they compare, see The Most Fuel‑Efficient Hybrid Cars In 2026: Top Picks, Real MPG, And Which One Fits You – Fixourfuel.
Fuel economy is only one line of ownership cost. Compare cars on the full picture:
- Fuel: use a real-world figure for your type of driving, not just the combined label number.
- Insurance and tax: get a quote for the exact car before you buy, because it can differ between similar models.
- Maintenance and repairs: a service history that matches the mileage is worth more than a slightly better MPG figure.
- Battery condition: for hybrids and EVs, the main risk to check before purchase.
Ranked on this basis, a well-maintained petrol compact usually offers the lowest-risk saving, a used EV rewards drivers with home charging, and a hybrid rewards buyers who confirm battery health first.
How to check a used car’s real MPG
You can narrow down real fuel economy before you visit the seller. Work through these steps in order:
- Find the exact model year. Look up the car on fueleconomy.gov, which is the federal source that comparison sites such as Big Green Purse draw their mileage estimates from.
- Note city and highway figures separately. Match them to your own driving rather than relying on the combined number alone.
- Compare with real-world tests. Where a test exists, such as the Civic and Elantra results above, use it to judge whether the model tends to beat or miss its label.
- Ask the seller for fuel records. Recent fill-up logs or a trip computer reading on a long, steady drive give you a car-specific figure.
- Run your own test. Drive a steady motorway stretch and a town stretch, then compare what the display shows with the rating for that trim.
- Inspect before you pay. Have an independent mechanic check the engine, transmission and, for hybrids and EVs, the battery.
If the car falls well short of its rating on a steady run, ask why before negotiating. Poor tyres, a service backlog or a fault may explain it, and each is a reason to lower the price or look elsewhere.
Frequently asked questions
Is fueleconomy.gov an official source?
Yes. Oak Ridge National Laboratory maintains the site for federal energy and environmental agencies, making it the go-to resource for checking the rating of a particular model year.
Is a used electric car cheaper to run than a petrol compact?
It can be, but it depends on charging access and your typical trip. EVs rate well in the city, so a mostly urban driver gains most, while a long-distance driver should look closely at the highway rating.
Is a used hybrid riskier than a petrol car?
It adds one extra check: the battery. Get the battery assessed independently before buying, and treat any refusal or unclear battery history as a reason to choose a different car.
Can I trust a seller’s quoted MPG?
Treat it as a claim to verify. Compare it with the rating for that exact model year and trim, then confirm it with your own test drive.
