This calculator is for informational purposes only and does not constitute medical advice. Results are estimates based on general formulas. Consult a qualified healthcare professional before making health decisions.
Target Heart Rate Calculator
Optimize your training with personalized heart rate zones.
Your Details
Used to estimate Max Heart Rate (220 - Age).
Optional. Improves accuracy (Karvonen formula).
Using Standard Formula. Enter Resting HR for better accuracy.
Training Zones
Heart rate zones translate cardiovascular training intensity into something you can actually monitor mid-workout. The five-zone model separates easy aerobic work from threshold sessions and maximal efforts — different zones produce different physiological adaptations.
Calculating max HR and the five zones
The calculator estimates max HR as 220 − age, the simplest and most widely used rule (other formulas such as Tanaka, 211 − 0.64 × age, exist but are not offered here). Zones as % of max: Zone 1 (recovery) 50–60%, Zone 2 (aerobic) 60–70%, Zone 3 (tempo) 70–80%, Zone 4 (threshold) 80–90%, Zone 5 (VO2max) 90–100%. If you enter a resting heart rate the Karvonen method is used instead: target = (max HR − resting HR) × intensity + resting HR, which suits people with notably high or low resting rates.
When to use this calculator
Use it to plan endurance training. Most well-designed endurance programs spend 80% of time in Zone 2 — the conversational pace that builds aerobic base and mitochondrial density — and 20% in Zones 4-5. Use the calculator to find your specific BPM ranges, then train inside them rather than going by perceived effort alone.
Worked example
A 35-year-old: max HR = 220 − 35 = 185 bpm. Zone 2 (60–70%) is 111–130 bpm and Zone 4 (80–90%) is 148–167 bpm. With a resting heart rate of 60 entered, the Karvonen version of Zone 2 runs from ((185 − 60) × 0.60) + 60 = 135 to ((185 − 60) × 0.70) + 60 = 148 bpm, noticeably higher than the simple percentage method, which is typical for fit individuals with a low resting rate.
Limits and assumptions
Maximum heart rate is estimated as 220 minus your age. If you enter a resting heart rate the zones switch to the Karvonen method, target = (max − resting) × zone percentage + resting; otherwise each zone is a straight percentage of the maximum. The five zones use fixed boundaries at 50, 60, 70, 80 and 90% and every beats-per-minute figure is rounded to a whole number.
The 220 − age rule is a population average and can be well off for an individual, and there is no field for a measured maximum from a test or a watch. Heat, altitude, fatigue and medication are not considered; the zones are for general endurance training guidance.
Frequently asked questions
How do I calculate my max heart rate?
This calculator uses 220 − age, the common rule of thumb. Other published formulas, such as Tanaka (211 − 0.64 × age), give slightly different figures for the same person and are not offered here. The most accurate way is a supervised maximal test, which is exhausting and unwise for untrained people; the peak reading from your hardest recent effort on a chest strap is a practical substitute.
What is Zone 2 training?
Low-intensity aerobic training, typically 60-70% of max HR — the pace where you can hold a conversation. Builds aerobic base, mitochondrial density, and fat oxidation. Most endurance athletes spend 80% of their training time in Zone 2.
What is the Karvonen heart rate formula?
Karvonen uses heart rate reserve (HRR) instead of just max HR. Target HR = ((max HR − resting HR) × intensity %) + resting HR. More accurate for fit individuals because it accounts for resting HR differences.
Guides for this calculator
- Zone 2 Training: Why the World's Best Athletes Train Slow
Learn why elite athletes train in Zone 2, how to calculate your heart rate zones using the Karvonen formula, and the science behind fat burning and endurance.