Heart Rate Zone Calculator — Max HR & Training Zones
Find your maximum heart rate and five cardio training zones based on your age. Use the zones to optimise fat burning, endurance, and peak performance training.
❤️ Calculate Your Heart Rate Zones
The 5 Heart Rate Training Zones Explained
Heart rate zones divide the range between resting HR and maximum HR into five bands, each producing different physiological adaptations. Training in the right zone for your goal is more effective than simply "working out harder."
Zone 1 — Active Recovery (50–60% Max HR)
Very light effort. Breathing is easy and conversational. Zone 1 is used for warm-ups, cool-downs, and recovery sessions between harder training days. It improves blood circulation and helps clear lactate from muscles without adding training stress. Walking, easy cycling, and gentle swimming typically sit in Zone 1.
Zone 2 — Aerobic Base / Fat Burning (60–70% Max HR)
Light to moderate effort. You can hold a full conversation. Zone 2 is the foundation of endurance training — the zone where your aerobic system becomes more efficient, mitochondrial density increases, and your body learns to use fat as its primary fuel source. Elite endurance athletes spend 70–80% of their total training time in Zone 2. Most recreational athletes spend too little time here, gravitating toward Zone 3 instead (the "junk miles" zone that's too hard to be truly restorative but not hard enough to drive meaningful adaptation).
Zone 3 — Aerobic Endurance (70–80% Max HR)
Moderate effort. Breathing is faster; you can speak in short sentences. Zone 3 improves cardiovascular efficiency and muscular endurance. It corresponds to a "comfortably hard" pace — a 5K or 10K race pace for many recreational runners. Some endurance protocols suggest limiting Zone 3 time and focusing on Zones 2 and 4 for a clearer training stimulus (polarised training).
Zone 4 — Threshold Training (80–90% Max HR)
High effort. Breathing is heavy; full sentences are difficult. Zone 4 training is around the lactate threshold — the exercise intensity at which lactate accumulates faster than the body can clear it. Training here raises that threshold, allowing you to sustain a higher pace before "going anaerobic." Tempo runs, cycling time trials, and rowing intervals often target Zone 4. Sessions here are typically 20–40 minutes and require 48+ hours of recovery.
Zone 5 — Maximum Effort (90–100% Max HR)
Maximum or near-maximum intensity. Conversation is impossible. Zone 5 training improves VO2 max (maximum oxygen uptake) and neuromuscular power. Sprint intervals, Tabata protocols, and hill sprints use Zone 5. Sessions are short (10–20 seconds to 2–3 minutes per interval), and total Zone 5 volume in a week should be small — typically 5–10% of total training time for most athletes.
How Maximum Heart Rate Is Calculated
This calculator uses the classic 220 − age formula, which remains the most widely known. For a 35-year-old, estimated max HR = 220 − 35 = 185 bpm.
However, this formula has a standard deviation of ±10–12 bpm — meaning two people of the same age could have max HRs that differ by 20–24 bpm. Alternative formulas include:
| Formula | Equation | Best For |
|---|---|---|
| Classic | 220 − age | General use, widely used |
| Tanaka (2001) | 208 − (0.7 × age) | More accurate for older adults (40+) |
| Gulati (women) | 206 − (0.88 × age) | More accurate for women |
| Fox (athletes) | 210 − (0.5 × age) | Fit individuals with higher max HR |
For the most accurate max HR, perform a max HR test: after a thorough warm-up, run or cycle at maximum effort for 2–3 minutes while wearing a heart rate monitor, checking the peak reading. Only do this if you are fit and have no cardiac risk factors.
Karvonen Method — Heart Rate Reserve
If you entered your resting HR above, the calculator uses the Karvonen method (also called Heart Rate Reserve), which produces more personalised zone boundaries:
Target HR = ((Max HR − Resting HR) × % intensity) + Resting HR
Because it accounts for your resting HR, the Karvonen method produces higher absolute bpm targets for the same percentage zone compared to the simple max HR percentage method. A fit person with a resting HR of 45 bpm will have higher Zone 2 targets than a sedentary person with the same age and max HR of 55 bpm — which more accurately reflects their higher baseline fitness.
Reference: Max HR and Zone 2 by Age
| Age | Est. Max HR | Zone 2 (60–70%) | Zone 4 (80–90%) |
|---|---|---|---|
| 20 | 200 bpm | 120–140 bpm | 160–180 bpm |
| 25 | 195 bpm | 117–137 bpm | 156–176 bpm |
| 30 | 190 bpm | 114–133 bpm | 152–171 bpm |
| 35 | 185 bpm | 111–130 bpm | 148–167 bpm |
| 40 | 180 bpm | 108–126 bpm | 144–162 bpm |
| 45 | 175 bpm | 105–123 bpm | 140–158 bpm |
| 50 | 170 bpm | 102–119 bpm | 136–153 bpm |
| 55 | 165 bpm | 99–116 bpm | 132–149 bpm |
| 60 | 160 bpm | 96–112 bpm | 128–144 bpm |
What Heart Rate Zone Should I Train In?
The right zone depends on your goal and current fitness level:
- General fitness / just starting out: Zones 1–2. Build the aerobic base first. Most beginners train too hard and burn out.
- Fat loss: Zones 2–3. But remember — total calorie deficit matters more than zone. Zone 2 is sustainable for longer sessions, which burns more total calories.
- Improving race pace / endurance: Mostly Zone 2 with 1–2 Zone 4 sessions per week (polarised training).
- VO2 max and peak fitness: Include Zone 5 intervals 1–2 times per week, with adequate recovery between sessions.
- Active recovery: Zone 1 only — keep it genuinely easy.