Cycling Power Zone Calculator

Cycling power zones divide the full range of effort into bands, each defined as a percentage of your FTP. Instead of riding by feel alone, zones let you target a specific physiological adaptation — aerobic base, threshold, or maximal aerobic power — by holding a defined watt range.

Because every zone is tied to FTP, the same percentage means a different watt target for every rider, and your own targets move as your fitness changes. That is the whole point: zones personalize intensity to you rather than prescribing the same watts to everyone.

How to use training zones

Zones are a tool for putting effort where it belongs. A few principles cover most of it:

• Most riding should be easy. The bulk of your weekly time belongs in Recovery and Endurance, even when it feels too gentle to matter.
• Make the hard parts genuinely hard. Threshold and VO2 Max work is potent but costly, so it should be a smaller slice and done when you are fresh enough to hit the numbers.
• Mind the middle.Drifting into Tempo on every ride — the "grey zone" — is the classic time-crunched trap: too hard to recover from, too easy to drive big gains.
• Recalculate after each FTP test. Stale zones quietly send you to the wrong watts.

Zone 2 training explained

Zone 2 (Endurance, roughly 56–75% of FTP) is steady, conversational riding. It builds your aerobic engine — capillary density, mitochondrial function, fat metabolism — and forms the foundation everything else is built on. It feels almost too easy, which is exactly why it is so often skipped. For how much you actually need, see how much Zone 2 you actually need and the Zone 2 vs Zone 3 trade-off for time-crunched riders.

Threshold training explained

Threshold work (around 91–105% of FTP) sits right at the power you can sustain for roughly an hour. Intervals like 2×20 or 3×12 minutes at threshold are the most direct way to raise FTP, because they train your body to clear and tolerate lactate at high sustained output. They are demanding, so they reward fresh legs and sensible spacing. Sweet Spot — just below threshold at about 88–94% — captures much of the same benefit for less fatigue, which is why busy riders lean on it.

VO2 Max training explained

VO2 Max intervals (106–120% of FTP) develop your maximal aerobic power — the ceiling above your threshold. Classic sessions are short and very hard, such as 5×4 minutes or 6×3 minutes with near-equal recovery. Done fresh, they lift the top of your aerobic range; done tired, they collapse into survival efforts with no real VO2 stimulus. Use them sparingly and when you can hit the targets.