Calculator
Heart Rate Zone Calculator
Your five training zones, worked out with a better formula than 220 minus age. Add your resting heart rate for a more accurate result.
Research has produced a separate maximum heart rate equation for women, which this uses.
From a lab test or a hard all out effort. A measured maximum beats any formula.
Heart rate reserve accounts for your resting rate and gives more useful zones for most people.
Measuring your resting rate
Count your pulse for a full 60 seconds before getting out of bed, on three separate mornings, then take the average. Most adults land between 60 and 100 and trained people often sit lower.
Estimates only. Formula based maximums carry a spread of roughly 10 beats either way, so treat these as starting points and adjust by feel. Beta blockers and some other medications lower your maximum heart rate substantially, which makes these figures wrong. Stop exercising and seek medical help for chest pain, severe breathlessness, dizziness or an irregular heartbeat.
Almost every heart rate zone calculator still uses 220 minus age. That formula came from a rough look at limited data in the 1970s and it misses badly at both ends of the age range. This heart rate zone calculator uses better validated equations and shows you the old number alongside so you can see the difference.
Below the tool you get why the old formula persists, what each zone is actually for, and the one medication that makes all of these numbers wrong.
Why 220 Minus Age Is Wrong
The formula has three problems.
It was never properly derived. The equation came from fitting a line through a handful of existing studies rather than from research designed to establish maximum heart rate. One of its own authors later described it as having no scientific merit.
The spread is enormous. Even where the average holds, individual maximums vary by roughly 10 to 12 beats either side. Two 40 year olds can genuinely differ by 20 beats.
It skews with age. The formula tends to overestimate maximum heart rate in younger adults and underestimate it in older adults. That means older people often train harder than their numbers suggest they should, and younger people train easier.
Better equations exist. This calculator uses the Tanaka equation of 208 minus 0.7 times age for men, and the Gulati equation of 206 minus 0.88 times age for women, which came from a study of over 5,000 women specifically.
For a 35 year old woman that produces 175 rather than 185. A 10 beat difference moves every zone boundary, which is enough to change what a workout actually does.
Percent of Max or Heart Rate Reserve
Two methods exist for setting zones and they produce different numbers.
Percent of maximum. Multiply your maximum by the zone percentage. Simple, and it ignores your resting rate entirely.
Heart rate reserve, also called the Karvonen method. Subtract your resting rate from your maximum to get your reserve, take the zone percentage of that, then add your resting rate back. This accounts for fitness, since a trained person with a resting rate of 48 has a much larger reserve than someone at 75.
Heart rate reserve gives more useful zones for most people, which is why the calculator defaults to it. Percent of max is available if your watch or coach uses it.
The two produce noticeably different Zone 2 boundaries, which matters because Zone 2 is where most training should happen.
What Each Zone Is For
| Zone | Effort | What it does |
|---|---|---|
| 1 · Recovery | Very easy | Blood flow and recovery between hard sessions |
| 2 · Aerobic base | Easy, conversational | Builds aerobic capacity and fat oxidation |
| 3 · Tempo | Comfortably hard | Sustainable hard effort, moderate benefit |
| 4 · Threshold | Hard | Raises the point where lactate accumulates |
| 5 · Maximum | All out | Improves peak oxygen uptake, short intervals only |
Zone 2 deserves most of your time. Endurance athletes typically spend around 80 percent of training here. It builds the aerobic base everything else sits on, and most recreational exercisers skip it because it feels too easy to be useful.
Zone 3 is the trap. Many people spend most sessions here without meaning to. It is hard enough to be tiring and not hard enough to drive threshold adaptation, so it accumulates fatigue without much benefit. Coaches call it the grey zone.
Zones 4 and 5 are potent and limited. One or two sessions a week is plenty for most people. More produces fatigue rather than fitness.
The Talk Test Beats Any Number
Heart rate has genuine limitations as a guide.
It lags behind effort. Your heart rate takes a minute or two to catch up at the start of an interval.
Heat, dehydration, caffeine, illness and poor sleep all raise it. The same effort can show 10 beats higher on a bad day.
Cardiac drift. Heart rate climbs during long sessions at constant effort, purely from rising body temperature and fluid loss.
The talk test cuts through all of that.
Zone 2. You can hold a full conversation in complete sentences.
Zone 3. Short sentences only.
Zone 4. A few words at a time.
Zone 5. No talking.
Use the numbers as a frame and the talk test to check them. Where they disagree, trust the talk test.
Measuring Your Resting Heart Rate
Accuracy here changes your zones, so it is worth doing properly.
- Measure before getting out of bed, since standing up raises it immediately.
- Count your pulse for a full 60 seconds rather than 15 seconds multiplied by four.
- Repeat on three separate mornings and take the average.
- Avoid measuring after a night of alcohol, poor sleep or illness.
Most adults land between 60 and 100 beats per minute. Trained endurance athletes often sit in the 40s or 50s.
A resting rate consistently above 90 is worth mentioning to a doctor, particularly alongside tiredness or breathlessness.
A rate that climbs by 5 to 10 beats over several days often signals fatigue, illness coming on, or under recovery. Many people track it for exactly that reason.
Medications That Change Everything
This section matters more than the rest of the article for the people it applies to.
Beta blockers. These lower both resting and maximum heart rate substantially, often by 20 to 30 beats. Every number this calculator produces will be wrong if you take them. Ask your doctor about using perceived effort or the talk test instead.
Some calcium channel blockers. Diltiazem and verapamil have similar effects.
Thyroid medication. Both under and over treatment shift heart rate.
Stimulants including caffeine and some decongestants. These raise heart rate at the same effort.
Anyone with a pacemaker, an arrhythmia or a known heart condition should get zone targets from their cardiologist rather than a formula.
When to Stop Exercising
Some symptoms mean stopping regardless of what your watch says.
- Chest pain, pressure or tightness
- Severe breathlessness out of proportion to the effort
- Dizziness or feeling faint
- An irregular or racing heartbeat that does not settle
- Pain spreading to the arm, jaw or neck
- Unusual fatigue with cold sweat
Chest pain during exercise needs medical assessment rather than a rest day. Our guide to body pain and when to see a doctor covers the warning signs in detail.
Anyone who has been inactive for a long stretch, lives with a chronic condition or is over 40 and starting vigorous exercise should speak to a doctor first. Our stair climb test guide covers a simple way to gauge where your fitness currently sits.
Frequently Asked Questions
Is 220 minus age accurate?
No. It was never properly derived, carries a spread of 10 to 12 beats either way, and skews with age. Better validated formulas exist and this calculator uses them.
What is the best formula for maximum heart rate?
Tanaka, which is 208 minus 0.7 times age, for men. Gulati, which is 206 minus 0.88 times age, for women. A measured maximum from a lab test or an all out effort beats any formula.
What is heart rate reserve?
Your maximum minus your resting rate. Zones calculated from reserve account for your fitness level, which percent of maximum does not.
Which zone should I train in most?
Zone 2 for most people, most of the time. It builds aerobic capacity and is sustainable. Endurance athletes typically spend around 80 percent of training there.
Why does my heart rate feel too high for the effort?
Heat, dehydration, caffeine, poor sleep, illness or stress all raise it at the same workload. Long sessions also cause cardiac drift, where heart rate climbs at constant effort.
Do heart rate zones work if I take beta blockers?
No. Beta blockers lower maximum heart rate substantially, so formula based zones will be wrong. Use perceived effort or the talk test and ask your doctor.
How do I find my true maximum heart rate?
A supervised lab test is the accurate way. A hard all out field test can approximate it and carries real risk for anyone with cardiac risk factors, so it needs medical clearance first.
Is a low resting heart rate always good?
Usually it indicates good fitness. A low rate alongside dizziness, fatigue or fainting is worth investigating, since it can also indicate a conduction problem.
Do smartwatch heart rate readings matter?
Wrist optical sensors are reasonably good at steady effort and less reliable during intervals and weight training. A chest strap is considerably more accurate.
Final Thoughts on Your Training Zones
A heart rate zone calculator gives you a frame rather than a prescription. Formula based maximums carry a spread of roughly 10 beats either way, so treat the boundaries as approximate and adjust by feel.
Two things matter more than precision. Spend most of your training in Zone 2, where it feels easy enough that you suspect it is not working. And use the talk test to check your numbers, since heart rate shifts with heat, sleep, caffeine and stress.
Anyone taking beta blockers or living with a heart condition should get zone targets from their doctor rather than any formula.
References
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology. PubMed
- Gulati M, et al. Heart rate response to exercise stress testing in asymptomatic women. Circulation. PubMed
- Centers for Disease Control and Prevention. Physical Activity Guidelines and Recommendations. cdc.gov
This calculator provides general estimates and does not replace advice from your doctor. Formula based maximum heart rates carry substantial individual variation. Beta blockers and several other medications lower maximum heart rate, which makes these figures inaccurate. Stop exercising and seek medical help for chest pain, severe breathlessness, dizziness or an irregular heartbeat. Read our full medical disclaimer and fact checking policy.