Page published October 27, 2026
Get the free Car Buyer’s Cheat Sheet, 7 things to know before you sign anything. The numbers that matter, in plain English, on one page.
Join the Driveonomics email list. Occasional useful updates, no spam, unsubscribe anytime.
If you never plug it in, the Prius Prime below costs $1,197 a year in fuel at 52 mpg gas only, not the $702 plugged in figure. That is still cheaper in fuel than a 30 mpg gas car at $2,075, but it gives up $495 a year against plugging in, or $2,475 over 5 years. Any page that shows you only the plugged in number is showing you half the car. This page shows both, plus gas and full EV, on the same basis.
What a plug-in hybrid actually is
A plug-in hybrid has a gas engine and a bigger battery than a regular hybrid, and you plug that battery in to charge it. For a short distance it drives on electricity alone, and when the battery runs low the gas engine takes over and the car runs as a gas hybrid. A regular hybrid is different: it never plugs in, its small battery charges itself while you drive and brake, and it is measured in mpg alone. A full EV is different again: it has no gas engine at all, so every mile is an electric mile and a dead battery means a charge, not a gas engine to fall back on. The plug-in hybrid sits between those two, and that is why its answer depends on behavior in a way neither of the others does.
One stated basis for every case on this page
Every fuel figure below uses the same inputs, so the cases compare cleanly. Change any input and the ranking can move, so run your own prices before deciding.
| Input | Value used on this page |
|---|---|
| Miles driven | 15,000 miles a year, the same yearly mileage the EPA uses for its annual fuel cost |
| Gas price | $4.15 a gallon, the average regular gas price in the AAA 2026 study cited on the EV vs gas page |
| Home electricity price | 18 cents a kWh, the average home electricity price in the same AAA 2026 study |
| What is counted | Fuel and electricity only. Purchase price, tax, insurance, upkeep, resale value, and charger installation are not in these tables |
| 5-year framing | The rounded annual figure times 5, with prices held flat. It is a framing device, not a forecast of future prices |
Worked comparison 1: the Prius Prime, four ways
The car is the 2024 Toyota Prius Prime SE, from EPA fueleconomy.gov figures rechecked at build on October 27, 2026: 127 MPGe combined on electricity, 52 mpg gas only, 26 kWh per 100 miles on electricity, and 44 miles of all electric range. The gas comparator is a 30 mpg gas car, the same comparator used in the EV vs gas worked example. The EV case is an EV at 3.3 miles per kWh, also from that example.
| Case | How the annual cost is worked out | A year | Over 5 years |
|---|---|---|---|
| Gas car, 30 mpg | 15,000 divided by 30, times $4.15 | $2,075 | $10,375 |
| Prius Prime, plugged in nightly, daily driving inside the 44 mile electric range | 15,000 times 26 kWh per 100 miles, times 18 cents | $702 | $3,510 |
| Prius Prime, never plugged in | 15,000 divided by 52, times $4.15 | $1,197 | $5,985 |
| Full EV, 3.3 miles per kWh | 15,000 divided by 3.3, times 18 cents | $818 | $4,090 |
Read the gaps, not just the ranks. Plugged in, the Prius Prime saves $1,373 a year against the gas car, or $6,865 over 5 years. Never plugged in, it still saves $878 a year against the gas car, or $4,390 over 5 years, because 52 mpg is a strong hybrid figure on its own. The cost of not plugging in is the gap between the two Prius Prime rows: $1,197 minus $702 equals $495 a year, or $2,475 over 5 years. That $495 is the yearly price of the habit, not of the car.
Formula
One stated basis for every case on this page: 15,000 miles a year, the same yearly mileage the EPA uses for its annual fuel cost; gas at $4.15 a gallon, the average regular gas price in the AAA 2026 study cited on the EV vs gas page; home electricity at 18 cents a kWh, the average home electricity price in the same AAA 2026 study; fuel and electricity only. The 5-year framing is the rounded annual figure times 5, with prices held flat. The Prius Prime is the 2024 Toyota Prius Prime SE, from EPA fueleconomy.gov figures rechecked at build on October 27, 2026: 127 MPGe combined on electricity, 52 mpg gas only, 26 kWh per 100 miles on electricity, and 44 miles of all electric range. Gas car, 30 mpg: 15,000 divided by 30, times $4.15, is $2,075 a year. Prius Prime plugged in: 15,000 times 26 kWh per 100 miles, times 18 cents, is $702 a year. Prius Prime never plugged in: 15,000 divided by 52, times $4.15, is $1,197 a year. Full EV at 3.3 miles per kWh: 15,000 divided by 3.3, times 18 cents, is $818 a year. Over 5 years those are $10,375, $3,510, $5,985, and $4,090.
Read the gaps, not just the ranks. Plugged in, the Prius Prime saves $1,373 a year against the gas car, or $6,865 over 5 years. Never plugged in, it still saves $878 a year, or $4,390 over 5 years, because 52 mpg is a strong hybrid figure on its own. The cost of not plugging in is $1,197 minus $702, which equals $495 a year, or $2,475 over 5 years. That $495 is the yearly price of the habit, not of the car. One result surprises people, and it is correct on fuel alone: the plugged in Prius Prime at $702 is cheaper in fuel than the full EV at $818, because the Prius Prime uses only 26 kWh per 100 miles, which is about 3.85 miles per kWh, against the EV example at 3.3 miles per kWh.
The RAV4 Prime is the same basis on the SUV version: the 2022 Toyota RAV4 Prime 4WD, rechecked at build on October 27, 2026: 94 MPGe combined on electricity, 38 mpg gas only, 36 kWh per 100 miles, and 42 miles of all electric range. Gas RAV4, 28 mpg: 15,000 divided by 28, times $4.15, is $2,223 a year. RAV4 Prime plugged in: 15,000 times 36 kWh per 100 miles, times 18 cents, is $972 a year. RAV4 Prime never plugged in: 15,000 divided by 38, times $4.15, is $1,638 a year. Full EV: $818 a year, as above. Over 5 years those are $11,115, $4,860, $8,190, and $4,090. Plugged in, the RAV4 Prime saves $1,251 a year against the gas RAV4, or $6,255 over 5 years. Never plugged in, it still saves $585 a year, or $2,925 over 5 years. The cost of not plugging in is $1,638 minus $972, which equals $666 a year, or $3,330 over 5 years. Note the flip against the Prius Prime: the plugged in RAV4 Prime at $972 costs more in fuel than the EV at $818, because an SUV uses 36 kWh per 100 miles. Size and efficiency decide the fuel ranking, not the badge on the car. MPGe is not mpg: 1 gallon of gasoline equals 33.7 kWh, so never put 127 into a gas cost formula. The EPA annual fuel cost of $800 for the Prius Prime and $1,050 for the RAV4 Prime is a different, blended EPA basis, so it will not match these tables.
One result surprises people, and it is correct on fuel alone: the plugged in Prius Prime at $702 is cheaper in fuel than the full EV at $818. That happens because the Prius Prime uses only 26 kWh per 100 miles, which is about 3.85 miles per kWh, against the EV example at 3.3 miles per kWh. A more efficient car costs less in fuel whatever its power source. Fuel alone does not settle the whole comparison: purchase price, insurance, upkeep, and resale value are not in this table, and they can move the total cost answer either way.
Worked comparison 2: the RAV4 Prime, the SUV version
The same basis, the second EPA car: the 2022 Toyota RAV4 Prime 4WD, rechecked at build on October 27, 2026: 94 MPGe combined on electricity, 38 mpg gas only, 36 kWh per 100 miles, and 42 miles of all electric range. The gas comparator here is the gas RAV4 at 28 mpg, from the hybrid page RAV4 pair. The EV row is the same EV case as above.
| Case | How the annual cost is worked out | A year | Over 5 years |
|---|---|---|---|
| Gas RAV4, 28 mpg | 15,000 divided by 28, times $4.15 | $2,223 | $11,115 |
| RAV4 Prime, plugged in nightly, daily driving inside the 42 mile electric range | 15,000 times 36 kWh per 100 miles, times 18 cents | $972 | $4,860 |
| RAV4 Prime, never plugged in | 15,000 divided by 38, times $4.15 | $1,638 | $8,190 |
| Full EV, 3.3 miles per kWh | 15,000 divided by 3.3, times 18 cents | $818 | $4,090 |
Plugged in, the RAV4 Prime saves $1,251 a year against the gas RAV4, or $6,255 over 5 years. Never plugged in, it still saves $585 a year against the gas RAV4, or $2,925 over 5 years. The cost of not plugging in is $1,638 minus $972, which equals $666 a year, or $3,330 over 5 years. Note the flip against the Prius Prime: the plugged in RAV4 Prime at $972 costs more in fuel than the EV at $818, because an SUV uses 36 kWh per 100 miles. Size and efficiency decide the fuel ranking, not the badge on the car.
Do not mix MPGe into a gas cost formula
MPGe is not mpg. MPGe converts electricity into a gasoline equivalent, where 1 gallon of gasoline equals 33.7 kWh, so that electric driving can be compared on an energy basis. It does not mean the car goes 127 miles on a gallon of gas. If you put 127 into a gas cost formula, you will get a fuel bill far below the real one. The correct figure for an unplugged plug-in hybrid is its gas only mpg: 52 for the Prius Prime and 38 for the RAV4 Prime. The correct figure for plugged in driving is its kWh per 100 miles: 26 and 36. That distinction is the whole reason the never plugged in case needs its own row.
The EPA annual fuel cost is a different basis, so it will not match
The EPA lists an annual fuel cost of $800 for the Prius Prime and $1,050 for the RAV4 Prime, on 15,000 miles and current fuel prices at the time the EPA page was prepared, with 55 percent city and 45 percent highway driving. Those are EPA blended figures, part electric and part gas, on EPA fuel prices. Our plugged in figures of $702 and $972 are our own arithmetic at $4.15 a gallon and 18 cents a kWh, for all electric driving in the plugged in case. Do not expect the two sets to match, and do not blend them. Use the EPA figures when you want the EPA basis, and use the tables above when you want one stated basis across gas, plugged in, never plugged in, and EV.
The behavior test: three questions before you buy
First, can you charge at home overnight? A driveway or garage outlet you control makes nightly charging easy. Street parking, an apartment lot with no outlet, or a landlord who will not allow charging makes it hard, and hard charging usually becomes no charging. Second, is your typical daily driving inside the electric range? The Prius Prime gives 44 miles and the RAV4 Prime 42 miles on electricity. A 30 mile daily round trip fits inside either range and lands near the plugged in row. A 60 mile daily round trip does not, and part of every day runs on gas, so the real result lands between the plugged in row and the never plugged in row, closer to the plugged in row when most miles are electric. Third, will you actually plug in every night? The cable, the routine, and the parking spot all have to line up, night after night. If the honest answer to the first question is no, the never plugged in row is your row, and the plug-in battery is giving you no fuel benefit over a regular hybrid at a similar gas mpg. Our are hybrid cars worth it page runs the regular hybrid math, with no plugging at all.
What fuel math leaves out
These tables count fuel and electricity only. They leave out the price difference between a plug-in hybrid and its gas or regular hybrid version, which this page does not quantify because no single like for like premium figure was verified at build. They leave out charger installation, which varies by home and panel; see how much it costs to install a home EV charger. They leave out insurance, upkeep, and resale value, which differ by car and driver. They assume home electricity at 18 cents a kWh for every electric mile, while public fast charging usually costs more, as the EV vs gas page notes, so a driver who charges mostly in public will land above the plugged in rows. EPA range is a test figure, not a promise for every trip: driving, speed, and weather move the real electric range. Run the full comparison in the calculator with your own prices, miles, and resale guess before deciding.
Figures: EPA fueleconomy.gov, 2024 Toyota Prius Prime SE and 2022 Toyota RAV4 Prime 4WD, rechecked October 27, 2026. Gas and electricity prices from the AAA 2026 study as cited on the EV vs gas page. Gas RAV4 28 mpg and gas Camry context from the hybrid page. All worked fuel figures are Driveonomics arithmetic on the stated basis.
Educational estimates only, not financial, tax, legal or insurance advice. Every figure on this page is a typical example worked from the inputs stated on the page, not a quote for a specific car, loan, or driver. Your rate, insurance, fuel use, and resale value will move your total. See Terms.
Calculation transparency
Scope. Fuel and electricity cost only, for a plug-in hybrid in four cases, gas car, plugged in, never plugged in, and full EV, on one stated basis, for two EPA cars, the Prius Prime and the RAV4 Prime.
Rules and time period. 15,000 miles a year, the same yearly mileage the EPA uses for its annual fuel cost; gas $4.15 a gallon and home electricity 18 cents a kWh, from the AAA 2026 study as cited on the EV vs gas page; EPA figures rechecked at build on October 27, 2026; 5-year framing is the rounded annual figure times 5, with prices held flat; purchase price, tax, insurance, upkeep, resale value, and charger installation are not in these tables.
Scope and limitations. Educational estimate only. Fuel alone does not settle the total cost: purchase price, insurance, upkeep, and resale value are not in these tables, and they can move the total cost answer either way. Public fast charging usually costs more than home electricity, so a driver who charges mostly in public will land above the plugged in rows. EPA range is a test figure, not a promise for every trip. No single like-for-like plug-in premium figure was verified at build, so none is stated. Prices vary by car, shop, and city. Get a written quote for your own car before you decide.
Source links checked November 6, 2026. Figures: EPA fueleconomy.gov, 2024 Toyota Prius Prime SE and 2022 Toyota RAV4 Prime 4WD, rechecked October 27, 2026; gas and electricity prices from the AAA 2026 study as cited on the EV vs gas page; gas RAV4 28 mpg and gas Camry context from the hybrid page; EPA annual fuel cost of $800 for the Prius Prime and $1,050 for the RAV4 Prime is a blended EPA basis, not this page basis. The AAA 2026 study figures are named only, not linked.
Primary sources: EPA fueleconomy.gov, 2024 Toyota Prius Prime SE; FuelEconomy.gov; EV vs gas; Are hybrid cars worth it. How the numbers are calculated is written down on the methodology page, and every source is listed on the sources page.
Definitions
Plug-in hybrid. A car with a gas engine and a bigger battery than a regular hybrid, and you plug that battery in to charge it. For a short distance it drives on electricity alone, and when the battery runs low the gas engine takes over and the car runs as a gas hybrid.
Regular hybrid. A hybrid that never plugs in. Its small battery charges itself while you drive and brake, and it is measured in mpg alone.
MPGe. Miles per gallon equivalent. It converts electricity into a gasoline equivalent, where 1 gallon of gasoline equals 33.7 kWh, so electric driving can be compared on an energy basis. It does not mean the car goes 127 miles on a gallon of gas.
kWh per 100 miles. The electricity a car uses per 100 miles. The Prius Prime uses 26, the RAV4 Prime uses 36.
Electric range. How far the car drives on electricity alone. The Prius Prime gives 44 miles and the RAV4 Prime 42 miles on EPA figures.
Gas only mpg. The miles per gallon on gas alone, with the battery empty. The correct figure for an unplugged plug-in hybrid: 52 for the Prius Prime and 38 for the RAV4 Prime.
Questions people actually ask
What is a plug-in hybrid, in plain words?
A plug-in hybrid is a car with a gas engine and a battery you plug in to charge. It drives a short distance on electricity alone, about 44 miles for the Prius Prime and 42 miles for the RAV4 Prime on EPA figures, and when the battery runs low the gas engine takes over and it runs as a gas hybrid. A regular hybrid never plugs in, and a full EV has no gas engine at all.
How much does a plug-in hybrid cost in fuel if I plug it in every night?
On this page basis of 15,000 miles a year, gas at $4.15 a gallon, and home electricity at 18 cents a kWh, a Prius Prime plugged in nightly with daily driving inside its 44 mile electric range costs $702 a year in fuel, or $3,510 over 5 years. A RAV4 Prime on the same basis costs $972 a year, or $4,860 over 5 years. Those figures assume all miles run on electricity; longer trips that use gas will cost more.
What happens if I never plug in a plug-in hybrid?
It runs as a heavier hybrid on gas only, at its gas only mpg: 52 mpg for the Prius Prime and 38 mpg for the RAV4 Prime. On this page basis that costs $1,197 a year for the Prius Prime, or $5,985 over 5 years, and $1,638 a year for the RAV4 Prime, or $8,190 over 5 years. That is still cheaper in fuel than the gas comparators on this page, but it gives up $495 a year for the Prius Prime and $666 a year for the RAV4 Prime against plugging in.
Is a plug-in hybrid cheaper in fuel than a full EV?
On fuel alone, it depends on efficiency, not on the badge. On this page basis a plugged in Prius Prime costs $702 a year against $818 for an EV at 3.3 miles per kWh, because the Prius Prime uses only 26 kWh per 100 miles. A plugged in RAV4 Prime costs $972 a year against the same $818 EV, because an SUV uses 36 kWh per 100 miles. Fuel alone does not settle the total cost: purchase price, insurance, upkeep, and resale value are not in these tables.
How do I work out my own plug-in hybrid fuel cost?
Split your miles into electric miles and gas miles. Electric cost is electric miles times kWh per 100 miles, divided by 100, times your electricity price per kWh. Gas cost is gas miles divided by gas only mpg, times your gas price per gallon. Add the two. If you drive inside the electric range every day and plug in nightly, most miles are electric miles. If you never plug in, all miles are gas miles at gas only mpg.
Related: See how much it costs to replace a hybrid battery.
Related: See the EV tax credits in plain words, including what is left for plug-in hybrids.
Related: See whether you should lease or buy an EV, the full-electric alternative.