Heart Rate Zone Calculator
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What Your Result Means
- Max Heart Rate: The estimated ceiling of your heart rate capacity, calculated as 220 minus your age. This is a population average — your true max may be 10–12 bpm higher or lower.
- Zone 1 (Light / Recovery): 50–60% of heart rate reserve. Comfortable effort used for warm-ups, cool-downs, and active recovery days.
- Zone 2 (Base / Aerobic): 60–70% of HRR. The "conversational pace" zone where most endurance adaptation happens. Long runs and easy rides typically target this zone.
- Zone 3 (Tempo): 70–80% of HRR. Moderate-hard effort that improves lactate threshold. Sustainable for 20–60 minutes in trained athletes.
- Zone 4 (Threshold): 80–90% of HRR. Hard effort near lactate threshold, typically sustainable for 10–30 minutes. Interval training often targets this zone.
- Zone 5 (Max): 90–100% of HRR. Near-maximum effort for short bursts. Used in sprint intervals and race finishes.
How This Calculator Works
You enter your age and resting heart rate. The tool estimates max heart rate using the standard 220−age formula, then applies the Karvonen method to calculate heart rate reserve (max HR minus resting HR). Each zone is a percentage range of HRR added back to resting HR. It assumes you know your true resting heart rate — measured first thing in the morning before getting out of bed.
Quick Questions
How accurate is the 220−age formula?
It has a standard error of about ±10–12 bpm, meaning your actual max heart rate could be meaningfully different. If precision matters — for race pacing or clinical purposes — a graded exercise test gives a measured max HR.
What resting heart rate should I enter?
Measure your pulse first thing in the morning, before caffeine or getting out of bed, for three consecutive days and average the results. A typical healthy adult resting HR is 60–80 bpm; trained endurance athletes may be 40–55 bpm.
Which zone should I train in most?
Most endurance training plans call for 70–80% of total training volume in Zone 2 (aerobic base), with the remainder split between higher-intensity zones. This "polarized" or "80/20" approach is well-supported by research for improving aerobic fitness.
Do heart rate zones differ for cycling vs. running?
Yes — max HR while cycling is typically 5–10 bpm lower than while running, because cycling uses less total muscle mass. If you train in both sports, consider sport-specific zone calculations.
Are there more accurate max HR formulas?
Tanaka et al. (2001) proposed 208 − 0.7 × age, which performs slightly better in older populations. Gulati et al. (2010) proposed 206 − 0.88 × age specifically for women. Both reduce prediction error compared to 220−age.
Sources
- CDC — Physical Activity Basics (target heart rate guidance)
- Tanaka et al. (2001) — Age-predicted maximal heart rate revisited (alternative max HR formula)
- ACSM Guidelines for Exercise Testing and Prescription (Karvonen method and training zone standards)
Method & review
Estimate only. Results reflect your inputs and standard formulas — they are not financial, tax, legal, health, or investment advice. Verify important decisions with a qualified professional.