Heart Rate Zone Calculator

Where the zones start, by age

Lower bound of each zone in bpm against age, percent-of-max method with a Tanaka max. Each zone runs from its line up to the next. Enter your age above and your Zone 2 floor lands on the chart.

Five zones, three ways to calculate them, one calculator. Enter your age for an estimated max heart rate or a measured max if you have one, add your resting heart rate for the Karvonen method, or your threshold heart rate for the most reliable zones of all. You get each zone in beats per minute, ready to type into a watch. The tables below cover zones by age, what each zone is for and how much of a training week belongs in it.

Three methods, one set of zones

Percent of max heart rate is the default on most watches: Zone 1 is 50 to 60 percent of max, Zone 2 60 to 70, Zone 3 70 to 80, Zone 4 80 to 90, Zone 5 90 to 100. Simple, and it works if your max is right. A 40-year-old with an estimated max of 180 gets a Zone 2 of 108 to 126 bpm.

Karvonen uses heart rate reserve, the span between your resting and maximum heart rate, and takes the same percentages of that span, added back on top of resting. Zone 2 for a max of 180 and a resting rate of 50 becomes 128 to 141 bpm, 20 beats higher than the percent-of-max version. That is not a quirk: a low resting heart rate means a fit heart, and the percent-of-max method underestimates how hard a fit person can work in every zone. If you know your resting heart rate, use Karvonen.

Threshold heart rate anchors the zones to a number you tested rather than one you estimated. The calculator uses Joe Friel's running bands: Zone 2 is 85 to 89 percent of threshold heart rate, Zone 4 is 95 to 99, Zone 5 starts at threshold itself. For a threshold of 170 that puts Zone 2 at 145 to 151 and Zone 4 at 162 to 168. Find your threshold with a 30-minute solo time trial: the average heart rate over the final 20 minutes is the number. Bike zones sit a few percent lower than running at the same threshold, so test on the bike for bike zones.

Getting the max heart rate right

Everything in the percent-of-max and Karvonen methods hangs on one number, and the number most people use is a guess. The 220-minus-age formula has a standard error of about 10 beats, which means the true max of a 40-year-old could be anywhere from 170 to 190 and the Zone 2 band moves by 12 beats with it. The calculator estimates max with the Tanaka formula, 208 minus 0.7 times age, which drifts less across the age range but is still a population average.

A measured max beats both. The cleanest field test is a hard hill: warm up 15 minutes, then run or ride up a two to three minute climb at a building effort, jog back, and repeat two or three times with the last one all out. The highest reading on the last repeat is close enough. A recent 5 km race or the final minutes of a hard interval session also work. Read resting heart rate first thing in the morning before you stand up, or take the seven-day average your watch reports.

What each zone is for

Zone 2 is the workhorse. Most of your weekly volume lives there because it builds the aerobic engine, improves fat use and leaves you fresh enough to do the hard sessions properly. Zone 3 is where most recreational athletes spend too much time: hard enough to need recovery, not hard enough to force adaptation. Zones 4 and 5 are the sessions that raise the ceiling, threshold work in 20 to 40 minute doses and VO2max repeats of three to five minutes, and they only work when the easy days were easy. The common split for an endurance week in a base phase is roughly 80 percent in Zones 1 and 2 and 20 percent in Zones 3 to 5. The zone table below has the feel, the talk test and the sessions for each.

Setting the zones on your watch

Garmin: Settings, User Profile, Heart Rate Zones. Pick "based on" percent of max, percent of HRR or percent of LTHR, enter the anchor number, and the watch fills the five bands, or type the bpm bounds from the calculator straight in. Set sport-specific zones if you run and ride. Polar and Coros work the same way. Apple Watch sets zones automatically from your health data and lets you enter manual bpm bounds under Workout, Heart Rate Zones. Whichever device you use, Movement Rebels reads the zones from your Garmin or Apple Health data and the coach plans sessions against the same bands you see on the wrist.

Why heart rate disagrees with your legs some days

Heart rate lags effort by a minute or two, which makes it a poor guide for short intervals and a good one for long steady work. It runs high in heat, after caffeine, on poor sleep and when you are dehydrated, and it drifts upward through a long session at constant pace. On those days the zone is still the zone; the effort that produces it is what changed. If Zone 2 feels far too easy or impossibly hard, the anchor is probably wrong, and the Zone 2 calculator verifies your ceiling with a heart rate drift test. For power-based zones on the bike, use the power zone calculator.

The five zones: what each one is and how much of your week it gets

The same five zones expressed three ways. Percent of max and percent of heart rate reserve use the same numbers by convention; the bpm they produce differ because reserve starts counting from your resting HR. Threshold percentages follow the Friel running model. The last column is the split most endurance coaches would recognise for a week in a base phase.

Percent of threshold: cycling zones sit a few percent lower than running at the same threshold HR; use a bike threshold test for bike zones.

Heart rate zones by age, 20 to 75

Estimated max HR (Tanaka) and the five bands as percent of max. Two people of the same age can have measured maxes 20 beats apart, so this table is the starting point, not the answer. Test your max, or at least use a resting HR, before you build a season on it.

Bands in bpm. The Zone 2 calculator verifies the Z2 ceiling with a heart rate drift test once you have a starting band.

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