Heart Rate Zones Calculator Guide: LTHR, Karvonen, Max HR, and Training Zones
Calculate heart-rate training zones from lactate-threshold heart rate, resting heart rate, or max heart rate, then use those zones for running, cycling, triathlon, and Zone 2 training.
A heart rate zones calculator is the fastest way to turn max heart rate, resting heart rate, or lactate-threshold heart rate into useful training targets. If you searched for "heart rate zones calculator", "LTHR zones", "Karvonen calculator", or "running heart rate zones", you are trying to train smarter without guessing every effort.
Heart rate is not perfect, but it is accessible. Runners, cyclists, and triathletes can use heart-rate training zones to control easy days, aerobic endurance, tempo work, threshold sessions, and recovery rides when power or pace is not the right tool.
Open the free heart rate zones calculator and use the result as the starting point for the training decisions below.
The Problem: Heart Rate Numbers Need Context
Max heart rate alone does not tell you where Zone 2 starts. Resting heart rate alone does not tell you threshold. Lactate-threshold heart rate needs a different zone model than basic percent-of-max formulas.
The TrainingDojo heart rate zones calculator supports practical methods so athletes can calculate HR training zones from the data they actually have.
What the heart rate zones calculator Gives You
- Heart-rate training zones in beats per minute.
- LTHR-based or heart-rate-reserve style targets depending on your inputs.
- Clear aerobic, tempo, threshold, and hard-effort ranges.
- A usable heart-rate framework for running, cycling, triathlon, and base training.
How to Use the Calculator
- Choose the method that matches your data: LTHR if you know threshold, or resting plus max heart rate for heart-rate reserve.
- Enter realistic values from a recent test or reliable wearable history.
- Use the zones for steady aerobic work and longer intervals, not five-second sprint pacing.
- Update zones after a new threshold test or major fitness shift.
Common Mistakes to Avoid
- Using the old 220-minus-age formula as if it were personal physiology.
- Treating heart rate as instant feedback during short intervals.
- Ignoring heat, dehydration, fatigue, caffeine, and cardiac drift.
- Copying another athlete's heart-rate zones instead of calculating your own.
Turn the Number Into Training
Heart-rate zones are especially useful for easy runs, endurance rides, long aerobic sessions, and recovery days. They keep endurance work honest when pace or power is distorted by hills, terrain, weather, or fatigue.
After calculating zones, use TrainingDojo to build a HR-based training plan with the right balance of Zone 2 volume, threshold work, recovery, and race-specific sessions.