Heart Rate Zone Calculator
Calculate your 5 heart rate training zones for running. Choose between the standard %Max HR method or the more personalized Karvonen (Heart Rate Reserve) method.
Calculate Your HR Zones
Enter your age or known max heart rate. Optionally, provide resting HR for the Karvonen method.
Understanding Heart Rate Training Zones
Heart rate zones divide your effort spectrum into five bands, each targeting different physiological adaptations. Training in the right zone ensures you're getting the intended benefit of each workout.
Zone 1 — Recovery (50–60% Max HR)
Very easy effort used for warm-ups, cool-downs, and recovery days. You should be able to hold a full conversation effortlessly. This zone promotes blood flow for recovery without adding training stress.
Zone 2 — Aerobic Base (60–70% Max HR)
The foundation of endurance training. Most of your weekly mileage should be here. Zone 2 builds mitochondrial density, capillary networks, and fat oxidation capacity. Comfortable and sustainable — the "talk test" pace.
Zone 3 — Tempo (70–80% Max HR)
Moderate effort that's "comfortably hard." Improves aerobic capacity and running economy. Tempo runs and steady-state efforts live here. You can speak in short sentences.
Zone 4 — Threshold (80–90% Max HR)
Hard effort at or near lactate threshold. Race-pace training for distances from 10K to half marathon. Builds the ability to sustain faster speeds. Speaking is limited to a few words.
Zone 5 — VO2max (90–100% Max HR)
Maximum effort. Short intervals of 1–5 minutes at near-maximal intensity. Develops peak aerobic power. Used sparingly — typically only 5–10% of total training volume.
%Max HR vs. Karvonen Method
The %Max HR method simply takes a percentage of your maximum heart rate. It's straightforward but doesn't account for individual fitness levels.
The Karvonen method (Heart Rate Reserve) uses the formula: Target HR = (Max HR − Resting HR) × % + Resting HR. By incorporating resting heart rate, it better reflects your individual cardiovascular fitness. A fit runner with a low resting HR of 50 bpm will get different zones than a beginner with a resting HR of 75 bpm, even if they're the same age.
Recommendation: If you know your resting heart rate, use the Karvonen method for more personalized zones.
How to Find Your Max Heart Rate
The 220 − age formula is a rough estimate with a standard deviation of ±10–12 bpm. For a more accurate number:
- Field test: After a warm-up, run 3 × 3-minute hill repeats at maximum effort. The highest HR recorded in the final repeat is close to your max.
- Race data: Your highest HR during an all-out 5K or 10K effort is typically within 2–3 bpm of true max.
- Lab test: A graded exercise test (VO2max test) gives the most accurate measurement.
How to Measure Resting Heart Rate
Measure first thing in the morning, before getting out of bed, on 3 consecutive days. Average the readings. A chest strap or smart watch worn overnight gives the most consistent resting HR data.
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Frequently Asked Questions
Is the 220 minus age formula accurate?
It's a rough population average with a standard deviation of ±10–12 bpm. Your actual max could be significantly higher or lower. If precision matters, do a field test or use the highest HR from a recent all-out race.
Which method should I use — %Max HR or Karvonen?
If you know your resting heart rate, use Karvonen. It produces more accurate, individualized zones because it accounts for your cardiovascular fitness level. If you only know your age, %Max HR is a fine starting point.
How much time should I spend in each zone?
The 80/20 rule is widely used: about 80% of training in Zones 1–2 (easy) and 20% in Zones 3–5 (moderate to hard). This polarized distribution is supported by research on endurance performance.
Why does my HR vary day to day at the same pace?
Heart rate is affected by sleep, hydration, temperature, stress, caffeine, altitude, and fatigue. Cardiac drift (HR rising during long runs at steady effort) is also normal. Use HR zones as guidelines, not rigid targets.
Do I need a heart rate monitor?
You don't need one, but it helps. Optical wrist sensors on modern watches are accurate enough for zone training. Chest straps are more accurate for intervals. You can also use perceived effort (RPE) as a proxy.