Heart Rate Zone Calculator
Get 5 training heart-rate zones in bpm using Karvonen or %MHR with Tanaka or Fox max HR.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this heart rate zone calculator
- Enter your age in years.
- Choose Karvonen (recommended) and enter your resting heart rate, or pick %MHR if you have not measured it.
- Select the max heart-rate formula — Tanaka (208 − 0.7·age) is the modern default; Fox (220 − age) is the legacy option.
- Click Calculate to see your 5 training zones as bpm ranges.
- Use Copy to save the table or Reset to clear inputs.
About this heart rate zone calculator
The Heart Rate Zone Calculator builds 5 training zones from your maximum heart rate. The Karvonen method (heart-rate reserve) is more individualised: it computes HRR = MHR − resting HR, then sets each zone as (zone% × HRR) + resting HR. The simpler %MHR method just multiplies the percentage by MHR. For maximum heart rate we default to the Tanaka 208 − 0.7·age formula, which has narrower published error than the older Fox 220 − age estimate. Five zones follow ACSM/Polar conventions: 50–60% (warm-up), 60–70% (fat burn), 70–80% (aerobic base), 80–90% (lactate threshold), 90–100% (VO₂ max). As a worked example, a 30-year-old with a 60 bpm resting HR has MHR = 208 − 0.7·30 = 187 bpm, HRR = 127 bpm, and a Karvonen Zone 2 of (0.60 × 127) + 60 = 136 to (0.70 × 127) + 60 = 149 bpm. This tool is for general education and is not medical advice — consult a qualified healthcare professional before starting intense training, especially with cardiovascular disease or beta-blocker medication.
FAQ
- Why is Karvonen better than %MHR?
- Karvonen scales zones to your individual heart rate reserve, so a fit person with a 45 bpm resting HR gets a different Zone 2 than someone with a 75 bpm resting HR. Pure %MHR ignores that difference.
- How do I measure my resting heart rate?
- Take it first thing in the morning, sitting upright, after a quiet minute — or read it from a wearable that averages overnight values. Take 3 morning readings and use the average.
- Should I use Tanaka or Fox for my MHR?
- Tanaka (208 − 0.7·age) has tighter validation across adults of all ages and is the modern default. Fox (220 − age) tends to overestimate MHR in young adults and underestimate it in older adults.
- My watch shows higher zones than this — why?
- Wearables may use lactate-threshold percentages, a measured MHR, or a personalised heart-rate-reserve model from your training history. Trust a tested MHR over any formula whenever you have one.
- What if I take beta-blockers?
- Beta-blockers blunt heart-rate response, so these formulas overestimate your true MHR. Use perceived exertion or have your prescriber set targets — do not rely on this calculator.