FTP Calculator: Bike Power and Heart Rate Training Zones

• Perform an all out 20-minute time trial on the bike. Make sure you do a good warm-up with some intense efforts in it, but we do not recommend doing the "blowout effort" (a max effort of 5 minutes in the warm-up) that you might have seen in other protocols. 
• Note that the time trial should be a maximum effort and represent your best possible performance closely. That is, if you pace poorly and leave a lot on the table through poor pacing, this data will not be representative of your best effort even if your actual exertion level was maximal. Another example is poor course selection, e.g. doing the test on a climb with a short descent in the middle that makes your average power output drop way below where it would have been on a consistent climb. 
• Make sure your equipment and data collection is on point. Calibrate your power meter and check that your crank length settings are correct. Do not use wrist-based heart rate monitoring. 
• With the test done, enter your input data (average power for the 20-minute test, and max heart rate for the same test) below and click Calculate. 
• You will get FTP and Max Heart Rate as output data, along with power zones and heart rate zones (if you choose to calculate heart rate training zones). 
• Training platforms like Training Peaks (and others) typically let you input your thresholds and training zones. Note that these platforms may have their own methods of calculating thresholds or training zones, but if you want to use the thresholds and zones here, you should input them manually, which most platforms (including Training Peaks) allow.

• FTP is calculated as 95% of your average power for 20 minutes. Note that we don't require you to do a "blowout effort" (5-minute max effort in the warm-up).
• Based on our data, 95% of 20-minute power (without a blowout effort) falls extremely closed to the more scientifically robust (but less practical) Critical Power (CP). Specifically, for 80% of athletes we've tested, the difference between FTP and CP is 5W or less. In other words, you can assume that your tested FTP using a 20-minute test is very close (likely within 5W) to where your Critical Power would be if you were to do a test (and by all means, you can try this and see if it holds up). 
• The differences between this calculator and other FTP-calculators are mainly 
  1) the Scientific Triathlon power-based zones differ from the original Allen and Coggan zones, only in that Zone 5 starts immediately above FTP, instead of at 105% of FTP as they do in the Allen and Coggan based zones.
  2) our calculator enables you to calculate more accurate (for the vast majority of people) heart rate zones, simply because we use Max HR as the reference point, instead of average heart rate. This doesn't mean the heart rate zones are perfect, but aside from a lab test or field lactate test, they are probably as good as they are going to get. 
• Bike power zones and heart rate zone calculations details can be seen in the tables below. 

Bike Power Zones

Bike Heart Rate Zones