If it's time to take your cycling fitness to the next level, then a power meter might be on your radar. By measuring a cyclist’s output in watts, a power meter can provide instant and valuable training data.

Here’s the rundown on power meter basics, an overview of the most popular models available, and a look at the cyclists who would most benefit from this cool piece of gear.

What Is a Power Meter?

Available to cyclists for over 30 years, a power meter measures a cyclist’s power output in watts. This is handy because it provides accurate, real-time data about your ride. Other common measurements, such as speed or heart rate, are not as stable. The weather, hilly routes, and even your daily caffeine consumption affects these measurements.

Wattage, however, provides instant and objective data. This makes it easier to track your progress as a cyclist over time.

So, what do these numbers mean? This equation determines power:

Instantaneous Power = Force × Angular Velocity

In cycling terms, force is also known as torque, or how hard you’re stomping on the pedals. Angular velocity, known as cadence, measures how fast you’re spinning those pedals; it's also the bicycle's revolutions per minute, or RPM. Power meters multiply your torque by cadence to determine your wattage output. In essence, stomp harder and spin quicker to make your wattage numbers higher.

Modern power meters tend to be small, almost weightless devices that attach to the pedals or crank of a bike. Most current models connect wirelessly through Bluetooth 4.0/Smart or ANT+.

For basic meters, prices range from a few hundred to a few thousand dollars. Lower-priced models are on the horizon. But for most riders, a power meter is still on the serious investment side of bike purchases.

The Different Types of Power Meter

Some of the most popular types of meters attach to your bike’s pedals, cranks, or bottom bracket. The best power meter for you will depend on your riding habits, budget, and desire for data accuracy.

Pedal

bicycle pedal

Pedal-based power meters work by measuring the force the cyclist creates through the pedals. Single-sided pedal power meters first calculate the wattage generated by one leg. Then they double that measurement to get the rider's total output. In addition, single-sided power meters such as the Garmin 3S are easy to install because you just switch out the pedals.

This makes it easy to use the meter on multiple bikes. Plus, they tend to have a lower price point than many other types of meters.

For riders who value greater accuracy in their data, dual pedal power meters calculate the output of each leg independently. This gives you the data needed to calculate pedaling efficiency and find any differences between the legs in terms of power output. Plus, gear such as the EXAKT dual powermeter can help measure your overall torque effectiveness.

In general, these advanced devices are more expensive than their single-pedal counterparts.

Crank

bicycle crank and chainring

Next up, the crankset is another location on the bike for meters. Some are located in the crank arm, or the piece that connects to the pedals. For example, the Stages Power Meter attaches to your existing crank arm, making it one of the more affordable power meter options available.

Like single-sided pedal meters, single crank power meters tend to measure the output of one leg, unless you include an extra sensor.

Meanwhile, devices such as the SRAM AXS Power Meter Spider are built into the crank spider, or part of the crank that attaches to the chain. Most spiders have between 3 and 5 arms. Spider-based meters can typically calculate the wattage output from both left and right legs by measuring the force applied on a strain gauge.

Bottom Bracket

bicycle with arrow pointing to bottom bracket

On a bicycle, the bottom bracket refers to the spindle and bearings that sit between the cranks. It attaches the crankset to the bike frame. This crucial bike part can also house a power meter.

Plus, bottom bracket power meters such as the PM812 can measure the wattage variations from both legs. This also places the power meter into a rather protected location on the bike, which is great for cyclocross or mountain bike enthusiasts who tackle tough terrains.

Several other types of power meters are available, including models that connect to your handlebars or hub, but these tend to be less common.

Do You Need a Power Meter for Indoor Cycling?

If indoor riding is more your speed, note that some devices such as the Kickr Smart Trainer and StagesBike SB20 Smart Bike already provide power data for workouts. In these cases, buying a separate power meter is unnecessary.

For this type of training, using an interactive cycling app such as Zwift or TrainerRoad can gamify the whole workout experience, encouraging you to crank up the watts like never before.

Who Needs a Power Meter?

For casual cyclists, power meters are probably not at the top of your wish list for bike gear. A bike computer that measures speed, distance, and GPS location may be more helpful. In fact, there are plenty of cycling apps available that provide all the data you need, and it’s easy to use your phone as a bike computer. There’s no need to buy a new device.

But if you’re looking to keep up with your local cycling club’s group rides, compete in a race, or blow past the competition in your virtual cycling app, then power meter data can be invaluable. Cyclists interested in road bikes, mountain bikes, cyclocross, triathlon, and many more two-wheeled sports may also benefit from the data offered by a power meter.

Lastly, people who enjoy crunching the numbers for the benefit of their fitness will appreciate the wealth of data these devices offer.

Rev Up Your Cycling

Once tech reserved for the pros, power meters are now more available and affordable for the average cyclist. With instant, accurate watt measurements, these devices turn your bike into a data-producing machine.

For the most part, any cyclist looking to seriously increase their fitness on the bike will benefit from these devices—the health metrics provided by a power meter are unrivaled.