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Training zones calculator

Enter your threshold: heart rate, running pace or power. Latu works out your zones with the same maths as the app. First how each zone feels, then the numbers.

Your threshold

What do you know?

Your heart rate at a pace you can hold for about an hour.

Without a value, the table shows where each zone sits relative to your threshold.

We store nothing you enter here. Your heart rate stays in your browser: in the link it sits after the #, and that part is never sent to us. Pace and power are in the address so you can share the result.

Your heart-rate zones

  1. Z1Recoveryup to 81 %Very easy: you could chat along the way.
  2. Z2EnduranceZone 282–89 %Easy: talking is comfortable.
  3. Z3Tempo90–93 %Moderate: full sentences still work.
  4. Z4Just below threshold94–99 %Strong: you can still say short sentences.
  5. Z5aJust above threshold100–102 %Hard: only a few words.
  6. Z5bVery hard103–106 %Talking hardly works any more.
  7. Z5cMaximalfrom 107 %All you have, only briefly.

Zones after Friel, as a percentage of your threshold heart rate.Source

Zone edges are estimates. Your breathing and how it feels confirm them.Source

What is zone 2?

Zone 2 is the easy endurance range: you can still hold a conversation. After Coggan it sits at 56 to 75 % of your FTP, after Friel at 82 to 89 % of your threshold heart rate. San Millán describes it as the highest effort at which your body clears lactate as fast as it produces it. He recommends 60 to 90 minutes in one go. That rests on observation, and no study has tested a minimum dose. So shorter easy sessions count too.Source 1Source 2Source 3

Is zone 2 the same everywhere?

No. In the heart-rate and power zones on this page, zone 2 is the easy endurance range. In the three-zone model Seiler uses to describe how elite athletes train, zone 2 is the middle range between the two thresholds. So when you read about zone 2, check which model is meant.Source

How do I find my threshold?

On the bike with an FTP test: after the warm-up, 5 minutes as hard as you can, 10 minutes easy, then 20 minutes all out. Your average power over those 20 minutes times 0.95 is your FTP. Test when rested and again after 4 to 6 weeks of training. A few watts either way are noise, not progress. For running, threshold pace is about the fastest pace you can hold for an hour, and your heart rate at that pace is your threshold heart rate. Daniels derives your training paces from a recent race time.Source 1Source 2Source 3Source 4

Why not use maximum heart rate or 220 minus age?

Rules of thumb based on age are rough, and none of Latu’s sources supports them. On top of that, a 2020 review found that fixed percentages of a maximum put different people into different metabolic ranges. So this tool works from your threshold, a measured value. These zone edges are estimates too. Your breathing and how it feels confirm them.Source

How much to eat on the way for each duration and pace is in the table Carbs per hour.

Latu is not a doctor. These numbers are a guide from sports science, not medical advice. If you have symptoms or a condition, talk to someone who knows about it first.

Your zones, in every session.

Latu plans your rides and runs in your zones, in watts, heart rate or pace. When a ride with power or a run shows a new threshold, Latu suggests it. It only applies once you say yes.

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