Max Heart Rate & Zones
Estimate your maximum heart rate and see training zones (1–5) for cardio intensity. Enter your age to get started.
Estimated max HR
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Enter your age.
Zones (based on % of max HR)
| Zone | % of max | Range (bpm) | RPE (approx.) |
|---|
RPE here is a simple tie-in: how hard the cardio effort feels, not lifting RPE for reps in reserve.
Understanding Heart Rate Training Zones
Heart rate zones give you a systematic way to control cardio intensity. Each zone represents a different physiological demand and training stimulus — working across the full spectrum produces more complete cardiovascular fitness than always training at the same pace.
What each zone means
- Zone 1 (50–60%): Active recovery. Very light effort — a gentle walk. Promotes blood flow without stressing recovery systems. Ideal on off days or between heavy training blocks.
- Zone 2 (60–70%): Aerobic base. Comfortable, conversational effort. Fat oxidation is highest here and mitochondrial adaptations accumulate. Endurance athletes do 70–80% of their cardio volume in Zone 2. This is the zone most people skip because it feels "too easy."
- Zone 3 (70–80%): Aerobic development. Breathing is harder; full sentences are difficult. Useful, but many athletes spend too much time here at the expense of Zone 2 — the "grey zone" that's hard enough to create fatigue without being intense enough to maximize aerobic adaptations.
- Zone 4 (80–90%): Lactate threshold. Hard effort sustainable for 20–60 minutes with focus. Improves your ability to work at high intensity for sustained periods.
- Zone 5 (90–100%): VO₂ max efforts. Sprint-level intensity sustainable for only 30–90 seconds. Used in HIIT protocols and track intervals.
Max HR formulas are estimates
Both the Tanaka (208 − 0.7 × age) and Fox (220 − age) formulas are population averages with a standard deviation of roughly ±10–12 bpm. Your actual max HR could be significantly higher or lower. Tanaka tends to be more accurate for older athletes (Fox overestimates max HR for people over 40). For truly accurate zones, a graded exercise test is required.
Cross-check with perceived effort
Use RPE (on the cardio scale: 1 = very easy, 10 = maximal) as a sanity check on your zones. Zone 2 should feel like a 3–4 out of 10 — sustainable indefinitely without significant discomfort. If your calculated Zone 2 range feels much too easy or too hard for that RPE, adjust your max HR estimate by 5–10 bpm and recalculate.
Want to know how much cardio to do without hurting your strength gains? Read Heart Rate Training for Strength Athletes for a practical conditioning guide built around these zones.