Heart Rate Zone Calculator

Find your zone 2 heart rate and all five training zones using the Gulati formula for women, built from women's data instead of the male-derived 220 minus age. Add your resting heart rate for zones personalized with the Karvonen method.

Your watch already knows this. Adding it switches the calculation to the Karvonen heart-rate-reserve method, which builds your zones off your own baseline instead of age alone.

This is a formula-based estimate, not a measured max heart rate or a training prescription. It describes the standard zone framework so you can see where your own effort falls.

Why 220 minus age is wrong for women

The formula most people know, 220 minus age, comes from a 1971 review of earlier studies that were overwhelmingly conducted on men. It became the default because it's simple, not because it was validated on women. In 2010, a study by Gulati and colleagues measured maximal exercise heart rate directly in a large cohort of asymptomatic women and produced a different formula: 206 minus 0.88 times age. For most adult ages, that lands lower than 220 minus age, which means the older formula tends to overestimate a woman's true max heart rate. Every zone calculated from an inflated max heart rate ends up inflated too, so your "moderate" effort might actually be your "hard" one.

What the five zones mean

Heart rate zones split effort into five bands, each defined as a percentage of your max heart rate (or, with the Karvonen method, a percentage of your heart rate reserve added to your resting heart rate). Zone 1 is a warm-up pace, zone 2 is the easy, sustainable pace that makes up the bulk of most endurance training, zone 3 is a moderate "tempo" effort, zone 4 is hard, and zone 5 is close to an all-out sprint.

Zone 2, specifically

Zone 2 (roughly 60 to 70% of max heart rate, or 60 to 70% of heart rate reserve with Karvonen) is an easy, conversational effort. You should be able to talk in full sentences without gasping, even if you'd rather not try to sing. It's the zone that shows up most often in endurance training research as the foundation of a training week, with harder efforts layered on top rather than replacing it. It's also the zone most people run too fast, because "easy" doesn't feel like it's doing anything.

Percent of max vs. Karvonen

The plain percent-of-max method just multiplies your estimated max heart rate by the zone percentage. The Karvonen formula uses heart rate reserve (HRR) instead: HRR = max heart rate − resting heart rate, and each zone's target is resting heart rate + (percentage × HRR). Because Karvonen factors in your resting heart rate, it produces zones that are more personalized to your own cardiovascular baseline than a straight percentage of a population-average max.

Up next: Curious what training apps can actually adjust for your cycle? See training around your cycle. Dialing in recovery too? Pair your zones with the protein calculator, or track your pattern with the cycle length calculator.

Common Questions About Heart Rate Zones

Zone 2 is the second of five heart rate training zones, roughly 60 to 70% of your max heart rate (or 60 to 70% of heart rate reserve if you use the Karvonen method with your resting heart rate). It's an easy, conversational pace: you can talk in full sentences, but singing would be a stretch. Most endurance training research points to zone 2 making up the bulk of a well-rounded training week, with harder zones layered in on top rather than replacing it.

The 220 minus age formula comes from a 1970s review of studies that were overwhelmingly conducted on men. When researchers later built a formula from a study population that included women (Gulati et al., 2010), the result was 206 minus 0.88 times age, which lands lower than 220 minus age for most adult ages. Using the male-derived formula tends to overestimate a woman's true max heart rate, which pushes every training zone built on top of it higher than it should be.

The Gulati formula estimates maximum heart rate for women as 206 minus 0.88 times age. It comes from a 2010 study (Gulati et al.) that measured maximal exercise heart rate in a large cohort of asymptomatic women, rather than extrapolating from the mostly-male data behind 220 minus age. It's still a population average and not a substitute for a measured max, but it's the better starting formula for women.

The Karvonen formula calculates training zones from heart rate reserve (HRR) instead of max heart rate alone. HRR is your max heart rate minus your resting heart rate. Each zone's bpm target is resting heart rate plus a percentage of HRR, for example zone 2 at 60 to 70% would be resting HR + 0.6×HRR to resting HR + 0.7×HRR. Because it accounts for your resting heart rate, Karvonen zones are more personalized than plain percent-of-max zones.

Yes. Resting and submaximal heart rate tend to run a few beats per minute higher in the luteal phase (after ovulation, before your period) than in the follicular phase, tracking the rise in progesterone and core body temperature. That means the same pace or effort can land in a slightly higher heart rate zone in the luteal phase than it would earlier in your cycle, even though the effort itself hasn't changed.

Estimate your max heart rate with the Gulati formula (206 minus 0.88 times age), then take 60 to 70% of that number for a plain percent-of-max zone 2. If you know your resting heart rate, the Karvonen method sharpens it further: subtract resting heart rate from max heart rate to get heart rate reserve, then zone 2 is resting heart rate plus 60 to 70% of that reserve. A watch that logs your actual resting heart rate over time will generally track closer to your real physiology than either formula alone.

A formula estimates. Weeks of workouts show you the real number.

Gulati and Karvonen are still population estimates, not a measured max. Gaia logs your actual heart rate zone time from every workout, so instead of guessing where zone 2 sits, you can see exactly how much of your training week you're really spending there.

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Educational content, not medical advice. This calculator applies published formulas to the numbers you enter; it does not measure your actual max heart rate and it is not a training plan. Heart rate response to exercise varies by fitness level, medication, heat, sleep, and many other factors beyond age and resting heart rate. Go Go Gaia is a tracking tool, not a substitute for professional medical or coaching guidance.