Your Threshold Functional Power (FTP) is arguably the most important metric to know if you’re training with power on the bike. It’s not because FTP is the be-all and end-all of your fitness level. Rather, FTP matters because all your power levels used in training are based on this number. This is why you should nail down a solid FTP test: go too hard and your performance levels might feel out of reach; Walk too light and you may have trouble making progress on the bike.
While your FTP basically indicates the pace you can maintain for an hour, most cyclists will not regularly perform a full hour-long FTP test, making it a poor method of testing FTP, even if it is the most accurate. Since your FTP will change as your fitness improves or decreases, you will test at least once a year if not more often. So it’s crucial to find a method that doesn’t put a lot of stress on your body or brain.
At the same time, you want an FTP test that reflects the pace you can maintain for an hour. That makes it difficult to find the right test — and when you switch between training programs, plans, or apps, you might find that the tests don’t align perfectly.
More from cycling
The final key: Avoid guessing your FTP or basing it on your number from years ago. Instead, choose the FTP test that works best for you and visit it regularly. Not sure which one to take? We explain how to find your FTP based on the best tests so you can find an accurate number and then use it to your training and performance advantage.
The classic DIY ways to find your FTP
20-minute FTP test
Most cyclists choose Hunter Allen’s classic 20-minute FTP test, and most apps use a version of it too. It’s a fairly simple protocol and can be done indoors or outdoors. In its simplest form:
- Warm up in Zone 1 and 2 (light effort) for 20-30 minutes and sprinkle in some 20-30 seconds of harder effort. When outside, find a flat route or a gently uphill road that you probably won’t have to stop for 20 minutes. Aim for minimal turns or descents. If you train indoors, use your trainer on a manual setting.
- Time to test! Press the lap button on your cycling computer so at the end you can easily see your average power for that 20-minute ride.
- Make it hard for 20 minutes, aiming for a pace that feels uncomfortable but sustained. You should be breathing heavily, but not gasping for air. Try to keep a consistent feeling throughout the 20 minutes. (For new cyclists, this test may not work the first time because you’re almost certainly starting way too hard and slacking off halfway through. If this happens, give yourself a week to recover and give it a try anew!)
- Press the round button again when you’re done.
- Cool down for at least 10-15 minutes with a light effort.
- Multiply the average effort from those 20 minutes by 0.95 to get your FTP (if you’re docking yourself, that 5 percent helps get you closer to the effort you could actually sustain for an hour).
For more information on Allen’s testing protocols, visit his blog here.
The 60 Minute FTP Test
The most honest of the FTP tests is the one where you actually exceed your limit for the full hour of effort that the other tests simply estimate. While it’s the most accurate, it’s also the most time-consuming, painful, and tiring—so it’s not easy to replicate.
Andrew Coggan is arguably the godfather of performance-based training – he was the person who coined the seven levels of performance, and Corote Training and racing with a power meter with Hunter Allen. He and Allen agree to disagree on the subject of FTP testing, as Allen favored the 20-minute test and Coggan favors the 60-minute test.
Unfortunately for most of us this won’t be realistic unless you have a great stretch of road that stretches for miles with a wide shoulder and no obstacles. And because this test is frankly no fun, none of the online platforms offer it as an option.
You can of course do it yourself and manually enter your FTP based on your result. It may be worth trying a 60 minute test at some point during your bike trip just to see how it feels to keep your FTP from a 20 minute test through the full 60 minutes. Otherwise we have other options for you.
The 4 best apps for finding your FTP
1. Optimize through Fascat App
FasCat uses the classic 20-minute FTP test, but with a more specific training protocol around the 20-minute test portion. In the “20-Minute Field Test,” warm up at 50 percent of your threshold for five minutes (which will feel very easy), then ramp up to your endurance pace for 10 minutes.
Then alternate between fast pace (FasCat owner Frank Overton’s favorite “sweet spot” zone) and threshold pace for about 20 minutes. This is followed by some rest, 30-second effort, and then more rest.
After these 20 minute intervals, you come into the actual 20 minute test portion of the workout. As with Allen’s protocol, your FTP is then calculated by taking the normalized power over the past 20 minutes and multiplying it by 0.95.
With more than 30 minutes of recovery, the entire workout takes an hour and 40 minutes.
2. Zwift app
Zwift offers three types of FTP tests: the classic 20-minute test, a shorter 12-minute version, and two ramp tests based on your weight that last 39 minutes and 43 minutes.
Ramp testing does exactly what the name suggests: you start with a low power level and gradually increase it while trying to maintain your cadence. When it becomes too difficult to maintain, you’ve hit your max – and your FTP is then calculated based on that information. Lighter riders and newer riders should opt for the Lite version of the Ramp Test in Zwift as it builds more gradually, which is important for light riders who may have great FTP but will struggle to steadily meet the muscular demands of big power jumps to fulfill .
Ramp tests are also generally great for beginners who may have trouble maintaining a pace for 20 minutes at a time, as it can be difficult to gauge what is and isn’t sustainable. They can also be a solid option for intermediate and advanced riders who want to test often but find the 20-minute test isn’t ideal for their training regimen.
3. Join app
This app offers three ways to find your FTP: the classic 20-minute test, a 12-minute test, and a ramp test.
The 12 Minute Test is a great in-between model for newer riders who may be struggling to figure out how to maintain a certain pace for 20 minutes. However, the farther you get from the 60-minute performance that FTP is meant to represent, the more inaccurate your test becomes.
If you choose to do the 12-minute test, multiply the normalized power from that effort by 0.85 to get your FTP. (The Join app does this for you if you use the app itself.) Note that you take a lower percentage on the 12-minute test because the effort you can sustain for 12 minutes is likely higher than what you do you can keep for 20 (and 60), so you have to make up the difference.
4. Main field
Peloton uses the 20-minute FTP test, although you can choose between two ride options with a warm-up and cool-down designed by trainer Matt Wilpers or Denis Morton. The premises remain the same as in the classic test: After a proper warm-up with some harder efforts, ride as hard as possible for 20 minutes.
The advantage of Peloton is that a coach guides you through the 20 minutes of the test, helping you to keep the pace and providing tips and motivation along the way.
It’s important to note that indoor trainer tests like this (or any conducted indoors) are likely to yield slightly different results than if you were riding outdoors. Some people test higher indoors, some lower – it depends on you and the terrain you ride outdoors.
The best way to keep track of your FTP
While it’s fun to experiment occasionally and see if your FTP differs between tests, when it comes to measuring your actual progress on the bike, stick to one method. Once you’ve chosen the method that works best for you, use that for future testing.
In other words, don’t alternate between a 20-minute test and a ramp test and a 60-minute test, says peloton coach Matt Wilpers. This will give you mixed results and won’t really show if your fitness is improving or declining.
Your test logs should look identical if possible. The only caveat is that it’s good to test both indoors and outdoors, as your smart trainer and power meter may measure slightly differently. Outdoor testing is subject to an increasing number of variations, such as headwinds, tailwinds, red lights or temperature changes – all of which can affect your test result. As Coggan points out, if you plan to ride or race outdoors, you should test these conditions.
How to find the best FTP test for you
As you can see most of the cycling specific apps available use the classic 20 minute test, but they also include options like ramp tests or shorter versions of the 20 minute test. This leads to the question: should you choose the test option that feels the easiest and gives you the slightly higher FTP, or the slightly harder test that gives you a lower FTP?
It’s likely that one of the tests will appeal to you more than the others: if you’re more of an all-day diesel driver, a longer test like the 20 or even 60 minute test might be better for you. Those who find they thrive on short, hard efforts may get better test scores by doing a ramp test.
Whichever test you prefer, it’s fine – remember that your FTP number sets the rest of your power-based zones for training. So make sure your perceived effort matches the force you should be exerting in each zone. (Use this power zone chart while cycling to see how your effort should feel for each power level.)
For example, if you find that your endurance effort feels a lot tougher than an “all-day pace,” it could be a sign that you need to adjust your FTP testing protocol to one that gives you more realistic cycling zones.
Molly writes about cycling, nutrition and training with a focus on women in sport. Her new mid-range series Shred Girls debuts in 2019 with Rodale Kids/Random House with Lindsay’s Joyride. Her other books include Mud, Snow and Cyclocross, Saddle, Sore and Fuel Your Ride. Her work has been featured in magazines such as Bicycling, Outside and Nylon. She is the co-host of The Consummate Athlete Podcast.