Heart Rate Zone Calculator
Calculate your 5 training zones based on Max Heart Rate or Heart Rate Reserve (Karvonen).
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- Athletic Performance
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- Stays local
Uses Heart Rate Reserve. More personalised — accounts for your resting heart rate.
Heart Rate Zones — Karvonen (HRR)
Active recovery. Very easy effort. Fat metabolism dominant.
Conversational pace. Builds aerobic base and mitochondrial density.
Comfortably hard. Marathon race pace for most athletes.
Hard effort. Improves lactate clearance and speed endurance.
Maximum effort. Short intervals only. Develops peak aerobic power.
Why results differ between methods: Each method calculates zones differently. Karvonen personalises for your resting HR. HRmax% is what Garmin/Polar use. MAF targets aerobic base building. Polarized reflects research-backed 80/20 training distribution.
For most athletes: use Karvonen or HRmax% for general training. Polarized if following a structured endurance plan.
Method and basis
How the figure above is derived, and when not to act on it.
Understanding the 5 Zones
Heart Rate training is about targeting specific physiological adaptations. 1. Zone 1 (Recovery): < 60%. Promotes blood flow and active recovery. 2. Zone 2 (Endurance Base): 60 - 70%. The "Fat Burning" zone. Builds mitochondrial density and capillary networks. You should be able to speak in full sentences. 3. Zone 3 (Tempo / Grey Zone): 70 - 80%. Often called "junk miles" because it's too hard for recovery but too easy for threshold gains. 4. Zone 4 (Threshold): 80 - 90%. Improves your ability to clear lactate. "Comfortably hard." 5. Zone 5 (VO2 Max): 90 - 100%. Peak aerobic capacity. Can only be held for a few minutes.💓 Heart Rate Training Zones
| Zone | Intensity (%) | Feeling | Benefit |
|---|---|---|---|
| Zone 1 | 50 - 60% | Very Easy | Recovery, Warm-up |
| Zone 2** | **60 - 70%** | **Conversational** | **Base Building, Fat Burn |
| Zone 3 | 70 - 80% | Moderate | Aerobic Capacity (Grey Zone) |
| Zone 4 | 80 - 90% | Hard | Lactate Threshold |
| Zone 5 | 90 - 100% | Maximum | VO2 Max, Anaerobic Speed |
🧮 Max HR vs. Heart Rate Reserve (Karvonen)
* Simple Max HR:220 - Age. Often inaccurate.
* Karvonen Formula**: Uses your **Resting Heart Rate (RHR) to determine your "reserve."
* *Formula*: (MaxHR - RHR) * % Intensity + RHR
* *Verdict*: Much more accurate for trained individuals.The 80/20 Rule
Elite endurance athletes spend 80% of their time in Zone 2** and only **20% in Zone 4/5. Spending too much time in Zone 3 leads to stagnation and burnout.WinSport Editorial & Research Standards
All formulas and reference values used in this tool are sourced from peer-reviewed scientific literature and validated clinical guidelines. Our research team continuously audits each calculator for accuracy and updates methodology as new evidence emerges.
Read the Science
Sports Science Articles- The Athlete Who Is Always Tired Is Not Always Overtrained. The Distinction Determines the Treatment.Overtraining syndrome (OTS) and functional overreaching (FOR) produce similar symptoms but require opposite responses. Misclassifying FOR as OTS — and reducing load when more recovery alone is insufficient — delays diagnosis and extends impairment.5 min read
- Two Athletes, Same Zone 2 Target — One Is Undertrained, One Is Overtrained. Here's Why.Most training apps use %HRmax for zones. The Karvonen HRR method tracks VO₂ reserve more accurately. Here's the difference — and why it matters for your aerobic base.5 min read
- Morning People and Evening People Are Not Just Personality Types. They Have Measurably Different Hormonal Environments at 6am vs 6pm — and Most Athletes Are Training at the Wrong One.Chronotype determines when your hormonal, neuromuscular, and cardiovascular systems peak. Learn how diurnal variation affects strength output, VO2max, and injury risk — and how to align your training schedule with your biological performance window.5 min read
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