CARDIO · HEART RATE
Heart Rate Zone Calculator
Calculate personalized training zones with the Karvonen method.
Try a preset
Result
Training zones
Karvonen target heart rates across the five training intensity bands.
How to use it
- Measure resting heart rate immediately after waking before getting out of bed (count pulse for 60 full seconds). Average 3 consecutive mornings for the most reliable baseline input for the Karvonen formula.
- Read your five zones: Z1 (recovery), Z2 (aerobic base — conversational), Z3 (tempo — challenging), Z4 (threshold — hard), Z5 (VO2 max — maximum). Zone boundaries are estimates ±5 bpm.
- Zone 2 is underused by most recreational athletes. Spending 70–80% of weekly training volume in Zone 2 (you can speak in full sentences) builds aerobic base, improves fat oxidation, and reduces injury risk over the long term.
- High-intensity work (Zone 4–5) should occupy no more than 20% of total training volume. More than this without sufficient Zone 2 base leads to performance plateau and elevated injury risk.
- Re-run this calculator every 2–3 months of consistent training. Improved cardiovascular fitness lowers resting heart rate, which shifts all zone boundaries — keeping your intensity calibrated to current fitness level.
Questions people usually ask
Which formula is used here?
Uses max heart rate and resting heart rate reserve (Karvonen) to build five intensity zones.
Can I use metric or imperial units?
Yes. This tool supports both metric and imperial units and remembers your preference.
Is this medical advice?
No. This tool provides general fitness estimates and should not replace medical guidance.
Is this tool free and private to use?
Yes. AI Fit Hub tools are free, no-signup browser tools. Inputs stay in your browser unless you choose to share a URL.
Do these tools replace medical guidance?
No. These outputs are general fitness estimates — not medical advice.
Can I switch between metric and imperial units?
Yes. Every tool supports both systems and remembers your preference in localStorage.
Related Resources
Learn the decision before you act
Every link here is tied directly to Heart Rate Zone Calculator. Use the explanation, formula, examples, and benchmarks to pressure-test the calculator output from first principles.
How To Use
5 STEPSHow to Use Zone 2 Heart Rate Calculator
Calculate your Zone 2 heart rate range using Maffetone, Karvonen, and percentage-based methods to optimize aerobic base training.
ReadHow To Use
5 STEPSHow to Use Heart Rate Zone Calculator
Optimize your workouts by learning how to use the Heart Rate Zone Calculator. Personalize training intensity for weight loss, endurance, or general fitness goals.
ReadHow To Use
5 STEPSHow to Use Sleep Calculator
Optimize your sleep and wake up refreshed! Learn how to use the AI Fit Hub Sleep Calculator to find ideal bedtimes and wake-up times based on sleep cycles.
ReadHow To Use
5 STEPSHow to Use Sweat Rate Calculator
Optimize your hydration strategy. This guide shows how to use the AI Fit Hub Sweat Rate Calculator to understand your fluid loss during exercise and prevent dehydration.
ReadGuide
6 MIN READHow to Improve Your VO2 Max
Boost your running performance and endurance by implementing expert-designed VO2 max training strategies. Learn specific workouts, intensity zones, and recovery tips to build aerobic capacity effectively.
ReadGuide
6 MIN READHow to Use Heart Rate Zones for Training
Optimize your running performance by mastering heart rate zones. Learn to calculate, apply, and adjust your training for improved endurance, speed, and recovery efficiently.
ReadContinue With Related Tools
Estimate your total daily energy expenditure using the Mifflin-St Jeor equation and activity multipliers.
Open →Convert your calorie target into daily protein, carbs, and fat grams based on your goal and split preference.
Open →Estimate required calorie deficit and timeline pacing for a bodyweight change target.
Open →Plan a realistic body-recomp timeline with body-fat targets, training frequency, calorie pacing, and protein guidance.
Open →