QUESTION: What’s a good FTP on Zwift? I’ve been riding with the app for a few months now on my Wahoo KICKR smart trainer, but I don’t know if my FTP is any good or not. How do you know? – Lee M
ANSWER: We’ve covered this subject in a different way, when someone asked about what a good average wattage is on the road. But let’s keep it strictly in Zwift terms for this answer.
In case you don’t know already, FTP stands for functional threshold power. That is basically your highest average power (your wattage) that you can maintain riding as hard as you can for an hour.
But here’s the problem. The wattage number by itself doesn’t mean very much! Because the lighter you are, the fewer watts you need to generate to go a particular speed. Or put the opposite way, the heavier you are, the more watts you’ll need to pedal to go the same speed as someone who is lighter than you.
That’s why if you race on Zwift, they don’t put you in categories based on your FTP. They use that number, but then divide it by your weight to give you an average watts per kilogram.
As an example, if you weigh 200 pounds and your FTP is 275 watts, then your power to weight ratio, or your watts per kilogram, is just over 3 watts per kilogram. That would put you in the C category of Zwift racing, and it would also give you the power profile of the typical Category 4 bike racer.
But if you weigh 150 pounds and you have that same FTP of 275, then guess what! Now your power to weight ratio / watts per kilogram is just over 4 watts per kilogram. That puts you all the way up at the bottom of the A category for Zwift racing, and give you the power profile of a typical Category 3 bike racer.
Weirdly, Zwift forces you to calculate your watts per kilogram yourself to figure out which category you should be racing. To do that, convert your weight in pounds to kilograms. Take your weight in pounds and divide by 2.2046 to get it into kilograms. Then take that number and divide your FTP by the correct number of kilograms.
Or just go to this page and let them do all the math for you….
Once you see your watts per kilogram number, you can see how “good” your FTP number is for you by looking at which category Zwift wants you to race in.
Here are how racers are split into categories on Zwift.
A = 4.0 w/kg and above
B = 3.2-3.9 w/kg
C = 2.5-3.1 w/kg
D = 2.4 w/kg and below
If you do much Zwift racing, you should also register over at Zwiftpower.com. After each Zwift race, Zwiftpower filters out all the people who are racing in your category who don’t have a heart rate monitor or a power meter, or who ride at a higher watts per kilogram level than is allowed in that category.
So by looking at your results at Zwiftpower.com, you’ll get a better idea of how you actually did against similar riders and you can ignore the sandbaggers or people who didn’t have their trainer set up in a way where you can verify that they were really riding that hard.