Heart Rate Training Zone Calculator
Find your personalised target heart-rate zones — the smart way, not the "220 − age" way.
This calculator uses the Karvonen method (also called the heart-rate reserve, or HRR, method). Unlike basic zone calculators, Karvonen factors in your resting heart rate — so two people the same age with different fitness levels get genuinely different zones.
For your maximum heart rate we use the Tanaka formula (208 − 0.7 × age), which research shows is far more accurate than the outdated 220 − age rule. Already know your true max from a test or our other tool? Tick the box to enter it directly for the most accurate zones.
For the best results, find your max heart rate first with our Max Heart Rate Calculator, then bring that number back here.
Calculate your zones
Sets the max-HR formula: Tanaka for men, Gulati for women.
How the calculation works
Most online zone calculators take a single percentage of your maximum heart rate. The problem is twofold: they usually start from the inaccurate 220 − age formula, and they ignore your resting heart rate entirely. We avoid both shortcuts.
The two-step method:
1. Max HR (Tanaka): MHR = 208 − (0.7 × age)
2. HR reserve (Karvonen): HRR = MHR − resting HR
Zone target = (HRR × zone %) + resting HR
The Karvonen method (heart-rate reserve) anchors every zone to both your ceiling (max HR) and your floor (resting HR). This is why it is rated moderate-to-good in the evidence hierarchy — better than a flat percentage of max HR, because it accounts for individual fitness. Two 40-year-olds, one with a resting heart rate of 45 and one with 75, will get noticeably different zones from the same workout intensity.
Why we don't use "220 − age"
The classic 220 − age formula is the most widely known — and the least reliable. Both the American College of Sports Medicine and the American Council on Exercise note it tends to overestimate max heart rate in younger people and underestimate it in older adults, with a standard deviation of about ±10–15 bpm. A 40-year-old's "180 bpm" max could realistically sit anywhere from 155 to 205 — and that error cascades into every zone beneath it.
The Tanaka formula (208 − 0.7 × age) was derived from a meta-analysis of 351 studies and is now the preferred age-based predictor in the research literature, especially for older adults. It is the default we use here. To go one step further, enter a max heart rate measured in a test.
Get your max heart rate first. The accuracy of every zone below depends on this number. Our Max Heart Rate Calculator uses the Tanaka and Gulati (women-specific) formulas — then tick "I know my max heart rate" above to plug it in.
What the zones are for
| % HRR | Intensity | Purpose | Talk test |
|---|---|---|---|
| 50% | Very light | Warm-up, cool-down and recovery | Can talk and sing comfortably |
| 60% | Light | Builds aerobic base and aids fat metabolism | Can hold a full conversation |
| 70% | Moderate | Improves aerobic fitness and endurance | Can talk but not sing |
| 80% | Hard | Raises lactate threshold and speed | Can only say a few words |
| 90% | Very hard | VO₂ max intervals — short bursts only | Can barely speak |
How accurate is this, really?
Heart-rate zones are valid and useful for general fitness, weight management and cardiovascular health — that five-zone framework is endorsed by the ACSM, the American Heart Association and the Mayo Clinic. A University of Wisconsin study found predicted-max zones placed people in the correct zone about 82% of the time, usually within 1–8 bpm.
The honest limitation: even a well-calculated Karvonen zone is anchored to a predicted max heart rate that still carries an individual error of roughly ±7–10 bpm. Large 2026 research on 1,411 runners also showed the real physiological breakpoints (ventilatory thresholds) don't land at fixed percentages — they vary with sex and fitness, and trained athletes hit them at different points than recreational exercisers. So treat these zones as a smart starting framework for general training, not as absolute boundaries.
The talk test is your free, real-world validator. Moderate intensity = you can talk but not sing; vigorous = you can only get a few words out. Use it at every zone, and remember that medications (especially beta-blockers), heat, caffeine and fatigue can all shift your true heart rate. If you have a heart condition, check with your doctor before training to higher zones.
When to upgrade to lab testing
For performance athletes or clinical populations, lab-measured max heart rate paired with VO₂ or lactate-threshold testing sits at the top of the accuracy hierarchy. Wearable devices that estimate lactate-threshold zones are also a meaningful step up from age-predicted formulas. For most general-fitness goals, though, the Tanaka + Karvonen approach here is more than enough to train effectively.
Next step: confirm your ceiling with the Max Heart Rate Calculator, or dial in your nutrition with the Daily Energy Needs Calculator.