Name: Flat Equivalent - Distance
Rating: 5 (1 reviews)
Author: BhSimon

The ‘flat equivalent’ (FE) metric is an innovative way to compare rides and routes. It is intuitive, simple, and useful.

The FE metric estimates the total work required to ride a route and uses that to calculate the equivalent cycling distance on a flat road. Basically, how far you would have cycled for the same effort if the road was perfectly flat. FE distance is more than just a theoretical measure. The calculation was derived using statistical regression analysis of real-world riding and is accurate to more than 90%, from a random sampling of rides from 600 cyclists on Strava.

Of course, everyone is different and there are important variables such as drafting, wind conditions, average power output, and so on, but this metric can to be interpreted as an average for cyclists, based on typical solo riding conditions.

The FE distance (in km) is calculated by:

Distance (in km) + [elevation gained (in metres) ÷ 20] – [elevation loss (in metres) ÷ 70].

The result is provided in the units preference (km or mi) set on your Edge device. The final FE distance for a ride is saved to the FIT file and will appear on Garmin Connect when the file is uploaded. 

The usefulness of the FE distance is that rides with different route metrics can be directly compared using a single indicator. Additionally, this value can be used to simply describe the accomplishment of a ride in a way that can be easily compared with other rides.

For example, riding 100 km (62 mi) with 1,200 m (3,937 ft) of elevation gain and 700 m (2,296 ft) of elevation loss would require the same work as riding 150 km (93 mi) on flat roads (100 + 1200/20 – 700/70). Another ride with entirely different metrics may result in the same FE distance, such as a 60 km (37 mi) ride with 2,500 m (8,200 ft) of climbing and descending. On first glance these rides do not seem to compare, but they both require the same overall effort (or work), equivalent to riding 150 km (93 mi) on a flat road.

FE distance makes it simple to compare routes and decide which one to take, removing the guesswork about which route is the hardest. For training, you can chose a route which suits the workload you are targeting. When deciding which route to take on a group ride, it will be easy for everyone to understand the difficulty of each route and make an informed decision.

You can learn more about the inspiration and origins of the FE distance metric from its creator, Data Science Cyclist, Prof. David Wilson, in this YouTube video: https://youtu.be/4oaQJy4FbkQ

A separate data field is available for showing the average FE speed on a ride. It is a useful tool for comparing efforts on rides with the same FE distance, as well as pacing while on a ride.