Heart Rate Zones Calculator
Stop guessing your effort — get your 5 heart rate training zones from your age, personalized with your resting heart rate.
Find your training zones
| Zone | Range (bpm) |
|---|---|
| Zone 1 — Recovery Easy walking, warm-ups, cool-downs. Barely feels like training — and that's the point. |
92–110 |
| Zone 2 — Aerobic base The fat-burning, endurance-building sweet spot. You can hold a conversation. |
110–128 |
| Zone 3 — Tempo Comfortably hard. Improves aerobic power; conversation gets choppy. |
128–147 |
| Zone 4 — Threshold Hard. Lactate threshold work — fast but sustainable for 20–60 minutes. |
147–165 |
| Zone 5 — Maximum All-out. Short intervals only; a few minutes total per session. |
165–184 |
Age-based estimate — individual max heart rates vary by ±10 bpm or more. A lab or field test gives your true number.
The 5 Heart Rate Zones Explained
Heart rate zones turn one number — your max — into a full training plan. Each zone stresses a different energy system:
- Zone 1 — Recovery (50–60%): easy walking, gentle cycling. Speeds recovery between hard days. You should finish feeling better than you started.
- Zone 2 — Aerobic base (60–70%): the most important zone most people neglect. Builds mitochondria, burns mostly fat, and you can sustain it for hours. About 80% of endurance training belongs here.
- Zone 3 — Tempo (70–80%): "comfortably hard." Great for race-pace work, but too hard for easy days and too easy for hard days — use deliberately.
- Zone 4 — Threshold (80–90%): just below the point where lactate accumulates faster than you clear it. The classic 20–40 minute tempo effort.
- Zone 5 — Maximum (90–100%): short, sharp intervals (30 seconds to a few minutes). Huge stimulus, huge fatigue — a little goes a long way.
How Max Heart Rate Is Estimated
This calculator uses the Tanaka equation: HRmax = 208 − 0.7 × age. It comes from a 2001 meta-analysis of 351 studies covering 18,712 people (Tanaka, Monahan & Seals, Journal of the American College of Cardiology) — far more solid ground than the old "220 minus age" rule, which was never properly validated and underestimates max heart rate in older adults.
No formula knows your heart, though. Individual max heart rates scatter about ±10–15 bpm around any age prediction. Treat the zones as starting points; if Zone 2 feels like Zone 4, trust your body over the math and consider a field test (e.g., a well-paced 30-minute max effort) or a lab VO₂ test.
Adding your resting heart rate switches the zones to the Karvonen (heart rate reserve) method: zone = resting + % × (max − resting). This personalizes the zones to your fitness — a resting HR of 50 vs 75 meaningfully shifts every boundary.
Worked Example: Age 35 Runner
Profile: 35 years old, no resting HR entered
Step 1 — max HR: 208 − 0.7 × 35 = 208 − 24.5 = 183.5 ≈ 184 bpm.
Step 2 — zones (percent of max):
Zone 1: 50–60% → 92–110 bpm · Zone 2: 60–70% → 110–128 bpm · Zone 3: 70–80% → 128–147 bpm · Zone 4: 80–90% → 147–165 bpm · Zone 5: 90–100% → 165–184 bpm.
With resting HR 55 (Karvonen): Zone 2 becomes 55 + 0.6–0.7 × (184 − 55) = 132–145 bpm — noticeably higher than the plain 110–128, because a low resting HR means a bigger reserve.
Why Zone 2 Training Matters
Zone 2 is having a moment in exercise science, and for good reason. At 60–70% of max, your body burns mostly fat, builds mitochondrial density, and clears lactate efficiently — adaptations that raise the ceiling for everything else. The polarized-training research (Seiler and others) consistently finds elite endurance athletes spend ~80% of training time at low intensity and only ~20% hard.
The mistake most recreational athletes make is the opposite: every run becomes a gray-zone Zone 3 grind — too hard to recover from, too easy to build top-end fitness. Slow down your easy days (really slow — conversational pace) and you'll have the freshness to go genuinely hard on hard days.
When to Retest Your Zones
- Every birthday — max HR drifts down ~0.7 bpm per year. Your zones quietly shift whether you update them or not.
- After 6–8 weeks of consistent training — resting HR usually drops as fitness improves, which changes Karvonen zones even at the same age.
- When zones stop matching effort — if Zone 2 pace at the same heart rate keeps getting faster, your fitness improved; recalculate with your new resting HR.
- After illness, detraining, or major life stress — heart rate runs high when the body is under stress. Retest when you're healthy.
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Frequently Asked Questions
What are heart rate zones?
Five intensity bands defined as percentages of your max heart rate: Zone 1 recovery (50–60%), Zone 2 aerobic base (60–70%), Zone 3 tempo (70–80%), Zone 4 threshold (80–90%), and Zone 5 maximum (90–100%). Each trains a different energy system.
How do I find my maximum heart rate?
The practical estimate is the Tanaka equation: 208 − 0.7 × age, based on a meta-analysis of 18,712 people. The only truly accurate way is a max-effort test (lab VO₂ test or a well-paced 30-minute field test). Individual max HR varies ±10–15 bpm around any formula.
What is Zone 2 training?
Training at 60–70% of max heart rate — brisk enough to matter, easy enough to hold a conversation. It builds mitochondrial density and fat-burning capacity, the aerobic base everything else rests on. Elite endurance athletes spend ~80% of training time here.
Is 220 minus age accurate?
Not very. The "220 − age" rule was never properly validated and it underestimates max heart rate in older adults. The Tanaka equation (208 − 0.7 × age) comes from a large 2001 meta-analysis and fits the data better across ages — which is why this calculator uses it.
Which zone burns the most fat?
Zone 2 (60–70%) burns the highest *percentage* of calories from fat, but total fat loss depends on total calories burned and your diet — higher zones burn more calories overall. For fat loss, combine mostly Zone 2 volume with a sensible calorie deficit.
Sources
- Tanaka H, et al. (2001) — Age-predicted maximal heart rate revisited, J Am Coll Cardiol (PubMed)
- Heart rate training zones explained — Tanaka & Karvonen methods