Claimed range vs real-world range: why they don't always match

When comparing different electric cars, it is common to look at the range advertised by each manufacturer. However, that figure corresponds to the WLTP range, an official testing cycle used to measure all vehicles under the same conditions.

Does this mean you will always be able to cover that many kilometres? Not necessarily.

In everyday driving, many factors come into play. A car driving through a city, where it can recover some energy thanks to regenerative braking, does not consume the same as one driving hundreds of kilometres on the motorway at a constant speed. Nor will it behave the same on a spring morning as it would on a freezing cold or scorching hot day.

For this reason, the real-world range of an electric car is usually different from the WLTP figure. Not because the official data is incorrect, but because every journey involves different driving conditions.

If you want to delve deeper into how low temperatures affect consumption, you can check out our article on electric car consumption in winter, where we look at the impact of the cold on the battery in more detail.

The best way to figure out how many kilometres an electric car can do in your specific case is to temporarily ignore the claimed figure and calculate the range based on your usual consumption and the type of journey you are going to make.

The formula for calculating the real range of an electric car

Although it might seem like a complicated calculation, you only actually need two pieces of data:

• The car's usable battery capacity, expressed in kWh.
• The average consumption, measured in kWh/100 km.

With this information, you can apply this formula:

Range (km) = (Usable battery (kWh) ÷ Consumption (kWh/100 km)) × 100

For example, if your car has a usable battery capacity of 60 kWh and consumes 15 kWh/100 km, the calculation would be:

(60 ÷ 15) × 100 = 400 km

Under these conditions, you could drive for around 400 kilometres before needing to recharge.

However, this result is not set in stone. If the journey is on the motorway, the weather is very cold, or you use the climate control for most of the trip, consumption will increase and the range will drop.

Here is the key: the battery doesn't change, but the consumption does. And it is precisely this difference that explains why the same car can offer wildly different ranges depending on the circumstances.

Total battery capacity, usable battery capacity, and state of charge: which figure do you need?

Before calculating your range, there is one detail worth checking: the usable battery capacity. This is one of those concepts that often goes unnoticed, but it makes all the difference when you want to know how far you can really go.

Many technical spec sheets highlight the total battery capacity. However, that is not the figure you should use for your calculation.

The total capacity is the maximum amount of energy the vehicle can store, whereas the usable capacity is the energy you can actually use to drive. The rest is kept in reserve by the manufacturer to protect the battery and help maintain its performance over time.

Let's look at an example. A car might advertise a 64 kWh battery but have a usable capacity of 60 kWh. It might seem like a small difference, but using one figure or the other changes the result of the calculation and affects how accurate your estimate will be.

It is also worth paying attention to the state of charge (SoC). Although the car allows you to charge the battery to 100% or run it down almost completely, many manufacturers recommend keeping the charge level between 20% and 80% for daily use. This simple habit helps to preserve the battery and maintain its performance for longer.

Later on, we will look at how to calculate the available range factoring in this margin, especially when planning a long journey.

Consumption in kWh/100 km: the figure that dictates range

If the battery is the car's energy 'tank', the consumption in kWh/100 km indicates how much electricity it needs to travel 100 kilometres.

It might seem like just another stat on the spec sheet, but it is actually the one that best explains why the range changes from one trip to another.

Consumption only needs to increase by a few kWh for the number of available kilometres to drop significantly.

Let's look at an example. Imagine a car with a usable battery capacity of 60 kWh.

What stands out the most is that a difference of just 5 kWh/100 km can translate into nearly 100 fewer kilometres of range.

This is why knowing your electric car's real consumption is much more useful than memorising the claimed range. You can easily find this figure on the trip computer or in the manufacturer's app, which usually displays the average consumption for recent trips.

Practical examples: city, motorway, winter, and long journeys

A simple way to understand how driving conditions affect range is to compare different scenarios with the same vehicle.

Let's take a very common example: a car with a usable battery capacity of 60 kWh.

These values are for guidance purposes, as every model consumes differently, but they highlight a reality: range changes depending on the conditions of use.

Therefore, if you are going on a long journey, it is best to calculate the range using the consumption expected for that trip, rather than the consumption you usually get driving around town.

The real-world factors that reduce range the most

You now know how to calculate the range of an electric car. However, this calculation is always based on an estimate. In practice, several factors can cause consumption to rise and available mileage to drop more than expected.

The good news is that they are all predictable. If you factor them in before you set off, calculating your range will be much easier, and the result will be much closer to reality.

Speed: the factor that makes the biggest difference

If there is one factor that has a particularly strong impact on an electric car's range, it is speed. Maintaining high speeds for long periods increases consumption and, consequently, reduces the number of kilometres you can cover on a single charge.

This is why the same car usually offers a longer range in the city than on the motorway. On urban journeys, regenerative braking recovers some energy when decelerating, whereas on the open road, this recovery is much lower.

This doesn't mean you have to drive slower than necessary; it's simply a matter of keeping in mind that speed is one of the factors that most heavily dictates the real-world range of an electric car.

Temperature and climate control

The battery also feels changes in temperature.

When it is freezing cold or scorching hot, some of the energy is diverted to keep the battery operating within its optimal temperature range. On top of that, you have to add the energy consumed by the heating or air conditioning, especially on longer journeys.

Does this mean you have to freeze or sweat it out to save battery? Not at all.

A step as simple as pre-conditioning the cabin while the vehicle is still plugged into the charge point can help reduce consumption during the first few kilometres of the trip.

The type of route

Not all journeys demand the same effort from the vehicle.

A flat road, a mountain pass, or a route with constant inclines will generate very different consumption rates. The same applies if you are travelling with a boot packed to the brim, using a rear-mounted bike rack, or installing a roof box: the extra weight and aerodynamic drag will also take their toll on the range.

Therefore, when calculating the kilometres you can cover, try to think about the actual route and not just the distance.

Driving style

There is one final factor that often goes unnoticed: how you drive.

Harsh acceleration, constant changes in pace, or unnecessary braking force the car to use more energy. Conversely, smooth, anticipatory driving helps you make much better use of every available kWh.

Simple habits, such as maintaining a steady speed or lifting off the accelerator early to take advantage of regenerative braking, can make a bigger difference than you might think on a long journey.

Ultimately, range does not just depend on the battery. It also depends on how you use the energy available to you.

How to calculate your usable range between charges

Although an electric car can travel a certain distance on a full charge, in your day-to-day life, you will rarely use the entire capacity of the battery.

In fact, many manufacturers advise keeping the charge level between 20% and 80%, as this margin helps preserve the battery and maintain its performance for longer.

Therefore, when planning a journey, it is more practical to calculate the range available within that window.

Let's look at the same example from the previous sections: a car with a 60 kWh usable battery and an average consumption of 15 kWh/100 km.

If you use 60% of the battery (from 80% down to 20%), you will have 36 kWh at your disposal.

(36 ÷ 15) × 100 = 240 km

In other words, you will be able to drive for approximately 240 kilometres before needing your next charge.

This calculation is not intended to be a strict rule. Its usefulness lies in providing a much more realistic benchmark for organising a trip and deciding where you should stop to charge, without having to run the battery down to the wire.

How to increase your range without changing your car

You can't change the capacity of the battery, but there are small steps you can take to help you cover more kilometres on every charge. Together, these habits help lower consumption and make better use of the available energy.

• Drive smoothly and maintain a constant speed whenever traffic conditions allow.
• Anticipate traffic to take advantage of regenerative braking and recover some energy when slowing down.
• Check your tyre pressure regularly. Incorrect tyre pressure increases rolling resistance and, with it, energy consumption.
• Avoid carrying unnecessary weight or installing accessories, like roof boxes, if you are not going to use them.
• Pre-condition the cabin before you leave while the car is still plugged into the charge point. This will reduce consumption during the first few kilometres.
• Plan your charging stops in advance, especially if you are heading on a long journey.

None of these tips will work miracles on their own. However, together they can make a noticeable difference to your range and help you travel with greater peace of mind.

From range to cost: how much energy you need to charge

Calculating your range also allows you to estimate how much energy you will need to recharge at the end of a journey and, consequently, how much that charge might cost you.

Let's look at an example. If you have driven 250 kilometres with an average consumption of 16 kWh/100 km, you will have used approximately 40 kWh of energy.

Knowing this figure is very useful for planning the costs associated with each trip, especially if you frequently charge your car at home.

In that case, having a specific electric vehicle tariff can help you optimise the cost of each charge. Discover Endesa's Electric Vehicle Charging Tariff, a solution designed to adapt to this type of consumption and make home charging easier.

Endesa Drive: a simple way to make the switch to electric mobility

Calculating range is just one part of the electric car driving experience. If you are thinking about making the leap to electric mobility, it is also worth considering aspects such as charging, maintenance, and the services that will accompany the vehicle throughout its lifespan.

With Endesa Drive, you have access to a solution that integrates the vehicle, a domestic charge point, and associated services, making the transition to driving an electric car much simpler. This way, alongside choosing a model that suits your daily range needs, you will have a solution designed to make electric mobility more convenient.

Frequently asked questions on how to calculate the range of an electric car

How do you calculate the real range of an electric car?

To calculate the range of an electric car, divide the usable battery capacity (kWh) by the average consumption (kWh/100 km) and multiply the result by 100. The result will be a very close estimate of the kilometres you will be able to travel under real-world conditions.

Why doesn't the real-world range match the WLTP range?

The WLTP range is obtained through an official testing cycle that allows different models to be compared under the same conditions. However, factors such as speed, temperature, road type, or the use of climate control mean that the real-world range can differ.

How far can an electric car go with a 60 kWh battery?

It depends on the consumption. For example, with an average consumption of 15 kWh/100 km, a usable battery of 60 kWh can offer a range of close to 400 kilometres. If consumption rises to 20 kWh/100 km, the range will drop to around 300 kilometres.

Does driving on the motorway consume more battery than driving in the city?

Generally, yes. At higher speeds, consumption increases, and regenerative braking has fewer opportunities to recover energy. Therefore, the range is usually longer in the city than on the motorway.

How do the cold and air conditioning affect range?

Extreme temperatures force the car to divert some energy towards keeping the battery running properly and regulating the cabin climate. As a result, consumption can increase and range can drop, especially on longer journeys.

What range do I need for my day-to-day life?

It depends on your regular journeys. If you use your car mainly to commute to work or get around the city, you probably don't need the maximum range available. The most important thing is to choose a vehicle that suits your needs and to have a convenient charging solution for everyday use.