How fast do electric bikes go? [E-Bikes Speed Guide]

Electric bikes, often referred to as e-bikes, have been on the market for years, but for many people, they remain something of a mystery. Despite their growing popularity, there’s still a lot of confusion surrounding how they work, what they’re capable of, and—perhaps most commonly—how fast they can actually go.

Even if you don’t ride an e-bike yourself, chances are you’ve encountered one on the road or cycle path. Knowing how fast they can travel, what laws regulate their speed, and how they differ from traditional bicycles is essential for staying safe and informed.

How fast do electric bikes go in the UK

In the UK, most electric bikes (e-bikes) are legally limited to a maximum assisted speed of 15.5 mph (25 km/h). While riders can go faster by pedalling or on downhill stretches, the motor will cut out once this limit is reached. Faster e-bikes, known as speed pedelecs or electric mopeds, are available but require registration, insurance, and a licence to be road legal.

Electric bike average speed km/h

The average speed of an electric bike (e-bike) isn’t a fixed number — it depends on several factors, including motor power, bike type, terrain, and even how much the rider pedals. For instance, commuter e-bikes equipped with 250W motors typically reach average speeds between 15–25 km/h (9–15 mph), which is ideal for city cycling and everyday travel. On the other hand, off-road or performance-oriented e-bikes with 500W motors can achieve higher speeds, often between 32–45 km/h (20–28 mph), making them more suitable for trails or private property where speed limits are less restrictive.

In the UK, strict regulations apply to what qualifies as an Electrically Assisted Pedal Cycle (EAPC). By law, the motor on an e-bike can provide assistance only up to 25 km/h (15.5 mph), and the motor power must not exceed 250W.

Any electric bike that exceeds these limits is no longer considered an EAPC — instead, it’s classified similarly to a moped or motorcycle. This means it must be registered with the DVLA, taxed, insured, and the rider must hold an appropriate license to use it on public roads.

How fast do electric bikes go without pedaling?

In the UK, the law sets strict limits on how fast an electric bike can travel using only its motor. Currently, the maximum legal speed for an electrically assisted pedal cycle (EAPC) is 15.5mph (25km/h) when using electric assistance. This means that, without pedaling, the motor can only propel the bike up to this speed — but only if the bike meets the legal standards and is officially approved for road use.

It’s important to note that this speed limit only applies to motor-assisted riding. Electric bikes are often equipped with a cut-off mechanism that automatically stops providing motor power once the bike exceeds 15.5mph. This ensures compliance with UK regulations, which also state that the motor must have a continuous rated power output of no more than 250 watts.

Of course, this doesn’t mean an e-bike can’t go faster. Riders can easily exceed 15.5mph by pedaling harder, riding downhill, or taking advantage of their bike’s gearing. In fact, many e-bikes are capable of much higher speeds if unrestricted. However, once the motor cuts out, any additional speed must come entirely from the rider’s own effort or gravity.

It’s also worth mentioning that some e-bikes — particularly those designed for off-road or private land use — can be modified or built to go much faster than the legal limit. These bikes often have more powerful motors and higher-capacity batteries, enabling them to reach speeds well above 20–30mph. However, using such bikes on public roads without proper registration, insurance, and licensing would make them illegal to ride as regular bicycles under UK law.

How fast do electric bikes go with assistance?

Under UK law, electric bikes are governed by the Electrically Assisted Pedal Cycle (EAPC) regulations. These rules state that:

• An ebike must have functional pedals and can only provide motor assistance when you are pedalling.
  

• The motor assistance must cut off at 15.5 mph (25 km/h). Once you exceed this speed, the motor stops providing extra power.
  

• The motor’s maximum continuous power output cannot exceed 250 watts.
  

If an ebike meets these criteria, it is treated like a normal pedal cycle. This means you can ride it on roads, cycle paths, and anywhere bicycles are allowed — no licence, insurance, or registration is needed.

How fast do electric mountain bikes go?

In most European countries, electric mountain bikes (e-MTBs) are subject to strict regulations to ensure they are classified as bicycles rather than motor vehicles. Under these rules, the motor is limited to a maximum continuous power output of 250 watts, and the pedal-assist system must be cut off once the bike reaches a speed of 25 km/h (about 15.5 mph). You can still go faster than that (e.g., downhill) using pedal power alone, but the motor won’t help you beyond this limit.

What factors affect the speed of electric bikes?

The speed of an electric bike (E-bike) depends on multiple interconnected factors, ranging from motor power to terrain. Understanding these variables can help you get the most out of your ride.

1. Understanding Watts: The Power Behind the Ride

Motor power plays one of the biggest roles in determining how fast your e-bike can go. In general, higher-wattage motors deliver more torque and top speed, but they also come with a higher price tag and often stricter legal limits.

For example, on completely flat terrain with no speed restrictions, top speeds for different motor powers can look like this:

In simple terms, the more powerful the motor, the less effort it takes for the bike to accelerate and maintain higher speeds.

2. Weight: The Load You’re Carrying

Just as pulling a sled is easier when it’s lightly loaded, an E-bike performs better with less overall weight.

• Bike weight: A heavy E-bike requires more energy to accelerate and maintain speed.
  

• Rider weight: A heavier rider means the motor must work harder to move the bike at the same speed as it would with a lighter rider.
  

Example: A 250 W motor can accelerate much more quickly when moving 50 kg than when moving 100 kg. This is why riders who carry extra gear (or ride with cargo attachments) often notice reduced acceleration and speed.

3. Terrain and Surface: What’s Beneath Your Wheels

The surface you ride on has a huge impact on speed and acceleration:

• Smooth, paved roads allow the motor to work efficiently, resulting in higher speeds.
  

• Loose or uneven surfaces (like gravel, sand, or dirt trails) create more rolling resistance, slowing you down.
  

• Inclines and declines: Gravity plays a role, too. Climbing hills forces the motor to work harder, reducing speed, while descending allows gravity to assist, making it easier to reach higher speeds.
  

4. Legal Speed Limits: The Law as a Limiting Factor

E-bikes can go faster than traditional bicycles, but laws often restrict their maximum assisted speed.

• In many countries, E-bike motors stop providing assistance once the bike reaches a regulated speed limit (for example, 20 mph in the U.S. or 25 km/h in much of Europe).
  

• Any speed beyond that point comes from your own pedaling effort—your “internal engine” of heart, lungs, and muscles.
  

This means that even if your E-bike has a powerful motor, its top assisted speed may be capped by legal requirements, with any additional speed entirely dependent on your physical input.

Electric Bikes Models from iScooter

Conclusion: 

In the UK, the speed of electric bikes is strictly regulated to ensure safety and distinguish them from mopeds or motorcycles. By law, a standard electrically assisted pedal cycle (EAPC) can provide motor assistance only while the rider is pedalling, and the motor must cut out once the bike reaches a maximum speed of 15.5 mph (25 km/h). 

Additionally, the motor’s continuous power output cannot exceed 250 W, and throttle-only operation is generally not permitted unless the bike meets special exemptions. Any e-bike that exceeds these limits—whether by achieving higher assisted speeds or using a more powerful motor—falls into the category of a motor vehicle, which requires registration, insurance, a driving licence, and the use of protective gear like helmets.