Free heart rate zone calculator

How to use the heart rate zone calculator

This heart rate zone calculator needs only your age. Type it in and you get an estimated max heart rate, a five-zone table in beats per minute (bpm) and your zone 2 range.

Two optional boxes make the result more personal:

• Resting heart rate. Add it and a second column appears with Karvonen zones. These use your heart rate reserve, which accounts for fitness.
• Measured max heart rate. If a lab test or a supervised maximal test gave you a real max, enter it. The calculator then skips the age formula.

You can also switch between three max heart rate formulas: 220 minus age, Tanaka and Gellish. The result updates as you type. The link in your address bar saves your inputs, so you can bookmark it or share it.

All results are estimates. The sections below explain where each number comes from and how far off it can be.

What are heart rate zones?

Heart rate zones are bands of effort defined by how fast your heart beats. Each band is a percentage range of your max heart rate. Low zones feel easy and you can hold them a long time. High zones feel hard and you can hold them only briefly.

Zone models are not a single standard. Brands and coaches draw the lines in different places. This calculator uses the five-zone model that both Polar and Garmin publish, which splits max heart rate into 10% steps from 50% to 100%.

Zone	% of max heart rate	Name (Polar)	How it feels (Garmin description)
1	50–60%	Very light	Relaxed, easy pace, rhythmic breathing
2	60–70%	Light	Comfortable pace, slightly deeper breathing, conversation possible
3	70–80%	Moderate	Moderate pace, more difficult to hold a conversation
4	80–90%	Hard	Fast pace, a bit uncomfortable, breathing forceful
5	90–100%	Maximum	Sprinting pace, unsustainable for long, labored breathing

Health bodies use broader bands. The American Heart Association and MedlinePlus put moderate exercise at about 50 to 70% of max heart rate and vigorous exercise at about 70 to 85%. The Cleveland Clinic gives 64 to 76% for moderate and 77 to 93% for vigorous. None of these is wrong. They are different ways of cutting the same range, so always check which model a number comes from.

How to calculate max heart rate

Max heart rate is the highest number of beats per minute your heart reaches during all-out effort. Every zone is a percentage of it, so this number drives everything else. There are three common ways to estimate it from age.

The 220 minus age formula

The best-known formula is simple:

Max heart rate = 220 − age

The American Heart Association, MedlinePlus and Polar all use it as their quick method. A 50-year-old gets 220 − 50 = 170 bpm.

It has a weak origin, though. A 2002 review by Robergs and Landwehr traced its history. They found it was not developed from original research. It came from an observation based on data from about 11 references. The same review reported that age-based estimates of max heart rate carry a large error, with a standard error of 7 to 11 bpm.

The Tanaka formula

Max heart rate = 208 − 0.7 × age

Tanaka, Monahan and Seals published this in the Journal of the American College of Cardiology in 2001. They pooled data from 351 studies covering 18,712 people. They then checked the equation in a lab study of 514 healthy adults, which gave an almost identical line (209 − 0.7 × age). The equation did not differ between men and women, or between active and inactive people.

The authors concluded that 220 minus age underestimates max heart rate in older adults. You can see this in the table further down. The two formulas agree at age 40 and drift apart after that.

The Gellish formula

Max heart rate = 207 − 0.7 × age

Gellish and colleagues published this in Medicine and Science in Sports and Exercise in 2007. Instead of comparing different people, they followed the same 132 people over 25 years. They used 908 maximal treadmill tests. Their result lands within about one beat of Tanaka at every age.

Which max heart rate formula should you pick?

If you are over about 40, Tanaka or Gellish is the better-supported choice. Both come from larger or longer data sets than 220 minus age. If your watch or class uses 220 minus age and you want your numbers to match it, use that. The calculator shows all three so you can see the spread.

Worked example: max heart rate and zone 2 at age 50

Here is the math the calculator runs, with real numbers.

Step 1: max heart rate (Tanaka). 208 − (0.7 × 50) = 208 − 35 = 173 bpm.

Step 2: zone 2 by percent of max. Zone 2 is 60 to 70% of max.

• 173 × 0.60 = 103.8, rounded to 104 bpm
• 173 × 0.70 = 121.1, rounded to 121 bpm

So zone 2 is about 104 to 121 bpm.

Step 3: zone 2 by the Karvonen formula. Say the same person has a resting heart rate of 65 bpm.

• Heart rate reserve = 173 − 65 = 108 beats
• Low end: 65 + (108 × 0.60) = 65 + 64.8 = 129.8, rounded to 130 bpm
• High end: 65 + (108 × 0.70) = 65 + 75.6 = 140.6, rounded to 141 bpm

So Karvonen zone 2 is about 130 to 141 bpm. That is higher than the percent-of-max range. This is normal, and the next section explains why.

What is the Karvonen formula?

The Karvonen formula sets training zones as a percentage of heart rate reserve instead of max heart rate. Heart rate reserve is your max heart rate minus your resting heart rate. The Cleveland Clinic notes that the heart rate reserve method is also called the Karvonen method. It is named after Karvonen and colleagues, who published a study on training and heart rate in 1957.

Target heart rate = resting heart rate + (max heart rate − resting heart rate) × intensity

Because resting heart rate is part of the formula, two people of the same age get different zones if one has a lower resting rate. That usually means the fitter person gets a wider working range.

Karvonen zones sit higher than percent-of-max zones at the same label. Percent of max starts counting from zero. Karvonen starts from your resting rate, which is already well above zero. So “60%” means a harder effort under Karvonen.

Garmin watches let you set zones as percent of heart rate reserve, and cardiac rehab programs have used it too. The Cleveland Clinic describes rehab targets of 60 to 80% of heart rate reserve plus resting heart rate.

This calculator applies the same five bands (50, 60, 70, 80, 90 and 100%) to your heart rate reserve. That lets you compare the two methods side by side. It is a common setup, but not the only one. Some coaches use different Karvonen bands.

Zone 2 heart rate by age

Here is zone 2 by age for all three formulas. Zone 2 is 60 to 70% of max heart rate. Max heart rate is rounded to the nearest beat, and the zone limits come from the unrounded max.

Age	220 − age: max	220 − age: zone 2	Tanaka: max	Tanaka: zone 2	Gellish: max	Gellish: zone 2
20	200	120–140	194	116–136	193	116–135
25	195	117–137	191	114–133	190	114–133
30	190	114–133	187	112–131	186	112–130
35	185	111–130	184	110–128	183	110–128
40	180	108–126	180	108–126	179	107–125
45	175	105–122	177	106–124	176	105–123
50	170	102–119	173	104–121	172	103–120
55	165	99–115	170	102–119	169	101–118
60	160	96–112	166	100–116	165	99–115
65	155	93–109	163	98–114	162	97–113
70	150	90–105	159	95–111	158	95–111
75	145	87–102	156	93–109	155	93–108
80	140	84–98	152	91–106	151	91–106

Two things stand out. First, the formulas agree closely between about 35 and 45. Second, by age 70 the gap between 220 minus age and Tanaka is about 9 beats at the max. That gap carries into every zone.

How to find your resting heart rate

Resting heart rate is how many times your heart beats per minute when you are fully at rest. The Cleveland Clinic says most people have a resting heart rate of 60 to 100 bpm, and athletes can be as low as 40.

To measure it well:

1. Take it before you get up, or after sitting quietly for a while. The Cleveland Clinic advises measuring when you are not drinking coffee, feeling stressed or moving around.
2. Find your pulse. MedlinePlus says to place your index and middle fingers on the inside of your opposite wrist, below the base of the thumb, or on the side of your neck next to the Adam’s apple.
3. Count the beats. Count for a full minute, or for 30 seconds and double it.
4. Repeat on a few mornings and use the average.

A chest strap or watch can also read resting heart rate. Many watches report it for you each day.

If your resting heart rate is often outside the usual range, or it changes suddenly, talk to a doctor. This calculator cannot tell you whether a resting rate is healthy.

How to read and use your heart rate zones

Your zones tell you how hard a session is in a way you can check mid-workout. Pick a zone for the goal, then keep your heart rate inside it.

Goal of the session	Zone to aim for	What the session looks like
Recovery or warm-up	Zone 1	Easy spinning, walking, light rowing
Steady base building	Zone 2	Long, even effort you can talk through
Moderate aerobic work	Zone 3	Steady pace, talking gets harder
Threshold and speed	Zone 4	Hard intervals of a few minutes
Short all-out efforts	Zone 5	Sprints of seconds to a minute or so

Keep these points in mind:

• Heart rate lags effort. It takes a little time to settle after you change speed. Judge a zone after you have held a pace for a while, not in the first few seconds.
• Heart rate drifts up. On a long steady session, heart rate can creep up even at the same pace. If it leaves the zone, slow down a little.
• Most weekly time goes in easy zones. The ACSM position stand advises at least 150 minutes a week of moderate exercise, or 75 minutes of vigorous exercise, or a mix. Hard zones are tiring, so most people keep them to short parts of a few sessions.
• Retest when things change. If your resting heart rate drops as you get fitter, the Karvonen zones will shift. Update your numbers now and then.

What is the talk test?

The talk test is a way to judge effort without any device. The CDC puts it simply. During moderate activity you can talk, but not sing. During vigorous activity you cannot say more than a few words without pausing for a breath.

This matches the zone descriptions well. Garmin describes zone 2 as a comfortable pace where conversation is possible. By zone 3, conversation gets harder.

Use the talk test alongside the numbers. If the calculator says you are in zone 2 but you can barely speak, trust the talk test. Your true max may be lower than the formula, which would put every zone too high.

How accurate are max heart rate formulas?

Age formulas are useful averages, but they can be off for any one person. Robergs and Landwehr reported a standard error of 7 to 11 bpm for age-based estimates. That means many people sit 10 or more beats away from their predicted max.

Here is what that looks like. Take a 40-year-old with a predicted max of 180 bpm. If their true max is 170, their real zone 2 is 102 to 119 bpm. If it is 190, zone 2 is 114 to 133 bpm. The formula’s 108 to 126 bpm sits between the two, but it is wrong for both.

The formulas may fit poorly if you:

• Take medicine that changes heart rate, such as beta-blockers
• Have a heart condition or a pacemaker
• Are a very fit endurance athlete or have trained hard for many years
• Are a child or teenager, since the studies looked at adults
• Are pregnant

The fix is a measured max, done safely. A lab test, or a test a qualified coach or clinician sets up, gives a far better number. Enter it in the measured max box and the calculator will use it.

Common heart rate zone mistakes

Treating the estimate as exact. A zone is a guide, not a line you must never cross. A few beats either side is fine.

Mixing methods. Percent-of-max zone 2 and Karvonen zone 2 are different ranges. If your watch uses one and your plan uses the other, your sessions will not match. Choose one.

Using a noisy sensor. A wrist sensor that jumps around on a bike or elliptical can push you out of zone for no reason. More on this below.

Testing max heart rate alone at home. An all-out test is hard on the heart. Do not try one alone, and get medical advice first if you have any risk factors.

Ignoring how you feel. If a zone feels far too easy or far too hard, your max may be off. Adjust with the talk test.

Chasing a fat burning number. Many machines label a low zone as fat burning. Use it as a description of effort, not as a promise. Total weekly activity is what the ACSM guidance is built on.

Heart rate zone training at home: treadmill, bike and rower

A home cardio machine makes zone training easy. You can hold a steady speed or resistance and watch your heart rate without traffic or hills.

Zone 2 on a treadmill

A treadmill lets you control both speed and incline. To stay in zone 2, set a brisk walk or easy jog, then adjust in small steps. Incline walking is a good option if running pushes you out of zone. Our guide to the best treadmills covers incline range and motor size. The treadmill pace converter turns mph into minutes per mile or km/h if your plan uses pace.

Zone 2 on an exercise bike

A bike takes impact out of the picture, which suits longer zone 2 sessions. Set a resistance you can hold at a steady cadence. A recumbent bike is comfortable for long, easy rides. An air bike gets harder the faster you pedal, so it can serve both easy rides and zone 4 or 5 intervals. See our best air bike picks.

Zone 2 on a rowing machine

Rowing uses the legs, back and arms together. Keep the stroke rate low and the effort even. A water rower’s feel changes with speed, which some people find helps hold a steady pace. Read what a water rower is or compare the best rowing machines.

Other options

A stair climber pushes heart rate up fast, so zone 2 needs a slow step rate. Walking counts too. The steps to miles calculator helps you track walking distance alongside heart rate.

Are chest straps more accurate than wrist heart rate monitors?

Yes. A chest strap reads the heart’s electrical signal, while most wrist devices read blood flow with light. In a Cleveland Clinic study published in 2017, 50 healthy adults exercised on a treadmill, a bike and an elliptical while wearing several devices. Each was compared with an ECG.

Device type	Agreement with ECG (Lin’s concordance, higher is better)
Polar H7 chest strap	0.996
Apple Watch	0.92
TomTom Spark Cardio	0.83
Garmin Forerunner 235	0.81
Scosche Rhythm+ forearm band	0.75
Fitbit Blaze	0.67

The machine mattered too:

• Treadmill: most devices did well, with agreement of 0.88 to 0.93. The Fitbit was lower at 0.76.
• Bike: only the Garmin, Apple Watch and Scosche passed the 0.80 mark.
• Elliptical with moving arms: none of the optical devices was accurate.

The authors concluded that chest monitors with electrodes should be used when accurate heart rate is needed. Rowers were not part of the study. Since rowing also involves strong grip and wrist movement, a chest strap is a safe choice there too. These results are for specific older models, so newer devices may differ.

Metric and UK readers

Heart rate zones do not change with units. Beats per minute are the same in the US, the UK and everywhere else, so the zone table works as-is. What does change is how you set the machine. UK treadmills often show km/h, and some plans give pace in minutes per km. Use the treadmill pace converter to switch between mph and km/h, then use this calculator to check the effort.

Who should see a doctor before zone training?

Most healthy adults can start easy cardio without a check-up. The ACSM position stand says the benefits of exercise outweigh the risks in most adults, and that medical consultation is useful when clinically indicated. It also advises gradual progression and knowing the warning signs of heart disease.

Talk to a doctor first if you:

• Take a beta-blocker or other medicine that lowers heart rate. The American Heart Association says your healthcare professional can find your new target heart rate, often with a brief exercise stress test. MedlinePlus notes that some blood pressure medicines can lower your target heart rate.
• Have high blood pressure, diabetes or a heart condition. MedlinePlus advises checking with your provider before starting exercise.
• Have chest pain, fainting, unusual shortness of breath or a racing or irregular heartbeat with exercise.
• Are pregnant or recovering from illness or surgery.

If you take heart rate lowering medicine, age-based zones will likely be too high for you. Use effort and the talk test until your doctor gives you a range.

Safety note

Heart rate zones are estimates for healthy adults, not a medical test. Warm up with a few easy minutes before harder zones. Stop and get help right away if you feel chest pain, pressure, dizziness, or a heartbeat that feels wrong. Do not do an all-out max heart rate test alone. If a zone feels too hard, slow down. The number on the screen is never more important than how you feel.