Hybrid cars explained: mild, full and plug-in hybrids compared
A hybrid car combines a petrol or diesel engine with an electric motor and battery. There are three main types: mild hybrids, which cannot drive on electric power alone; full hybrids, which can drive on electric power for short distances and charge themselves; and plug-in hybrids, which have a bigger battery you charge from a socket, giving typically around 30 miles of electric range.
This guide explains how each type works, what hybrids cost to run, who they suit, and what to check when buying one.
Last updated 29 September 2026. The figures come from RAC guidance, Auto Express and Top Gear (see the sources at the end).
Key takeaways
- Mild hybrids assist the engine but cannot run on electric power alone, and you do not plug them in.
- Full hybrids can run on electric power for short distances and charge themselves through braking and the engine.
- Plug-in hybrids have a larger battery and need charging, and typically offer around 30 miles of electric range.
- Hybrids can use up to 30% less fuel per mile than conventional cars, according to the RAC.
- A plug-in hybrid only saves money if you charge it regularly.
- From the second year, hybrids pay the same standard car tax as petrol cars.
In this guide
- What are the different types of hybrid car?
- How does a hybrid car work?
- Are hybrid cars cheaper to run?
- Why plug-in hybrids only work if you charge them
- Which type of hybrid is right for you?
- How do you look after a hybrid?
- What should you check when buying a used hybrid?
- Frequently asked questions
- Sources and further reading
What are the different types of hybrid car?
| Type | Can it drive on electric power alone? | Do you plug it in? | How it works |
| Mild hybrid (MHEV) | No | No | A small electric motor and battery assist the engine, mainly during acceleration and in stop-start traffic. Energy from braking recharges the battery |
| Full hybrid (HEV), often called self-charging | Yes, for short distances at low speeds | No | A larger motor and battery can move the car alone at times. The engine and braking recharge the battery |
| Plug-in hybrid (PHEV) | Yes, typically around 30 miles, and up to about 75 miles in some models | Yes | A much larger battery that you charge from a home socket, a wallbox or a public charger. The engine takes over when the battery is low |
The labels can be confusing. The RAC notes that ‘self-charging hybrid’ is a marketing term for full hybrids, which cannot be plugged in. Auto Express also points out that some manufacturers call mild hybrids simply ‘hybrids’, which can be misleading, because they cannot run on electric power alone. Examples of full hybrids include the Toyota Prius and Corolla, and examples of plug-in hybrids include the Mitsubishi Outlander PHEV, BMW 330e and Ford Kuga PHEV.
How does a hybrid car work?
In a hybrid, the car’s computer decides automatically when to use the engine, the electric motor, or both. You do not need to change how you drive. The main trick is regenerative braking: when you slow down, the motor works in reverse, capturing energy that would otherwise be lost as heat and storing it in the battery. That stored energy is then used to help move the car, which reduces fuel use.
Because the car does the work for you, most hybrids have an automatic gearbox. If you are learning to drive, our guide on manual vs automatic licences explains what that means for your licence.
Are hybrid cars cheaper to run?
The RAC says hybrids can use up to 30% less fuel per mile than conventional cars. How much you actually save depends on how and where you drive.
- Purchase price: hybrids typically cost more to buy than the equivalent petrol car, and plug-in hybrids usually cost the most.
- Fuel: you save most in stop-start town driving. On long, steady motorway runs the advantage tends to shrink.
- Charging (plug-in hybrids only): electricity is generally cheaper per mile than petrol or diesel, but only if you charge regularly.
- Car tax: from the second year, all cars registered from April 2017 pay the same standard rate, whatever the fuel. The expensive car supplement applies to hybrids with a high list price. See how much is car tax in 2026/27.
- Insurance: premiums depend on the car, your age and your history. See how to insure a hybrid or electric vehicle.
Why plug-in hybrids only work if you charge them
A plug-in hybrid only saves money if you plug it in. Top Gear points out that if you never charge one, you are effectively driving a regular car with a lot of extra weight, and the brochure fuel economy figures, which can be in the triple digits, are unlikely to be reached in real life. The RAC says a plug-in hybrid can suit people who live in a city, have regular access to charging, and mostly make journeys of under 30 miles.
Which type of hybrid is right for you?
| Your situation | Likely best fit |
| Mostly short journeys and you can charge at home or work | Plug-in hybrid |
| Lots of town driving and stop-start traffic, no home charger | Full hybrid |
| You want lower fuel use without changing your habits or budget much | Mild hybrid |
| Mostly long motorway miles | Compare a hybrid with an efficient petrol or diesel car, because the hybrid advantage can shrink |
| You can charge easily and want zero exhaust emissions | A fully electric car might suit you better. See whether it is time to switch to an electric car |
How do you look after a hybrid?
Hybrids need regular servicing like any other car, and the maintenance picture is a mix of the old and new:
- Brakes: regenerative braking can reduce pad wear, but brakes used less can corrode, so have them checked at each service. See what your brakes are telling you
- The 12-volt battery: hybrids still have a conventional battery that runs the car’s systems. If it fails, the car may not start
- The high-voltage battery: manufacturers usually offer a battery warranty, so check the terms if you are buying a used hybrid
- Jump starts: you can usually jump start only the 12-volt battery, and the RAC says not to use a hybrid as the donor car unless the manufacturer allows it. See how to jump start a car safely
- Servicing: most hybrids follow an annual schedule. Our guide to how often to service a car explains the basics
What should you check when buying a used hybrid?
- Ask for the full service history and check the warranty status, especially for the battery
- Check the type: mild, full or plug-in. They are very different cars
- For a plug-in hybrid, make sure the charging cable is included and that the car actually charges
- Check whether it is ULEZ compliant. See how to check if your car is ULEZ compliant
- Use our guide to checking a used car before you buy it
Frequently asked questions
Do hybrid cars need to be plugged in?
Only plug-in hybrids do. Mild and full hybrids charge their batteries through the engine and braking, so you just fill them with fuel as normal.
Are hybrid cars cheaper to run?
Often, especially in stop-start driving. The RAC says they can use up to 30% less fuel per mile, but they cost more to buy, and plug-in hybrids only save money if you charge them regularly.
What is the difference between a hybrid and a plug-in hybrid?
A plug-in hybrid has a larger battery that you charge from an external source, so it can drive much further on electric power alone. A standard hybrid cannot be plugged in.
Do hybrids pay car tax?
Yes. From the second year, cars registered from April 2017 pay the same standard rate whatever the fuel. The first-year rate is lower for cars with lower CO2 emissions.
How long do hybrid batteries last?
They are designed to last many years, and manufacturers usually offer a battery warranty. Check the terms for the specific car, especially if you are buying one second-hand.
Are hybrids automatic?
Most are. If you learn in an automatic, you will get an automatic-only licence, which covers hybrids and electric cars.
Is a hybrid cheaper to insure than a petrol car?
It depends on the car, your age and your driving history, rather than the fuel type alone, so compare quotes for the exact model.
Can I drive a hybrid on electric power all the time?
Not usually. Only plug-in hybrids and, for short distances at low speed, full hybrids can drive on electric power. Mild hybrids cannot.
Sources and further reading
- RAC Drive: What is a hybrid car and should I buy one?
- RAC Drive: Hybrid, plug-in hybrid or electric car?
- Auto Express: What is a hybrid car?
- Top Gear: What is a mild hybrid, and how is it different to a full hybrid?
About this guide: Rooster is a UK car insurance provider. This guide is general information for UK drivers. Fuel savings, range and prices vary by model and driving style, so check the figures for the exact car you are considering.
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