Target Heart Rate Calculator

About Target Heart Rate Calculator

How Maximum Heart Rate Is Estimated

The most common formula is:

Max HR = 220 - Age

This formula was first proposed by Fox et al. in 1971 and remains the most widely used despite its simplicity. It gives a population average - individual max HR can vary by 10-20 BPM in either direction. For a more accurate number, a graded exercise test with a cardiologist is the gold standard.

Age	Estimated Max HR	Typical Resting HR (trained)	Heart Rate Reserve
20	200 BPM	55-65 BPM	135-145 BPM
30	190 BPM	55-70 BPM	120-135 BPM
40	180 BPM	60-75 BPM	105-120 BPM
50	170 BPM	60-75 BPM	95-110 BPM
60	160 BPM	60-80 BPM	80-100 BPM

The Five Training Zones

Zone	% of Max HR	Purpose	Feel	Example (Max HR 190)
Zone 1 - Recovery	50-60%	Warm-up, cool-down, active recovery	Very easy, can talk freely	95-114 BPM
Zone 2 - Fat Burn	60-70%	Aerobic base, fat metabolism	Comfortable, can hold a conversation	114-133 BPM
Zone 3 - Cardio	70-80%	Cardiovascular fitness, endurance	Moderate effort, can speak in short sentences	133-152 BPM
Zone 4 - Threshold	80-90%	Lactate threshold, anaerobic capacity	Hard, can only say a few words	152-171 BPM
Zone 5 - Max	90-100%	VO2max, max speed / power	All-out effort, cannot speak	171-190 BPM

Simple % vs Karvonen Formula

The Karvonen formula uses heart rate reserve (HRR) to produce more personalised zones:

Target HR = ((Max HR - Resting HR) x % Intensity) + Resting HR

Method	Formula	Zone 2 (60-70%) for Age 30, RHR 60
Simple %	Max HR x %	114-133 BPM
Karvonen (HRR)	(Max HR - RHR) x % + RHR	138-151 BPM

The Karvonen method produces higher zone values because it accounts for your resting heart rate. It is considered more accurate for trained individuals whose resting HR is significantly below average.

How to Measure Resting Heart Rate

Step	Instructions
1	Measure first thing in the morning, before getting out of bed
2	Sit or lie still for 2-3 minutes to settle
3	Count your pulse for a full 60 seconds (or 15 seconds x 4)
4	Repeat over 3-5 mornings and take the average

Typical resting heart rates: sedentary adult 70-80 BPM, moderately active 60-70 BPM, well-trained athlete 40-55 BPM. Lower resting HR generally indicates better cardiovascular fitness.

Training Distribution

Most evidence-based training plans follow an 80/20 principle: about 80% of training time in Zones 1-2 (easy) and 20% in Zones 3-5 (moderate to hard). This polarised approach, supported by research on elite endurance athletes, builds a strong aerobic base while allowing adequate recovery.

Training Goal	Zone Distribution	Weekly Example (5 sessions)
General fitness	70-80% Zone 2, 20-30% Zone 3-4	3-4 easy runs, 1-2 moderate runs
Weight loss	60-70% Zone 2, 20-30% Zone 3, 10% Zone 4	Mostly Zone 2 with some tempo work
Race performance	80% Zone 1-2, 10% Zone 3, 10% Zone 4-5	4 easy runs, 1 interval session
Recovery week	100% Zone 1-2	All easy sessions, reduced volume

Heart Rate Zone Myths

Myth	Reality
"The fat burn zone burns the most fat"	Zone 2 uses a higher percentage of fat for fuel, but higher-intensity zones burn more total calories and more total fat per minute
"220 minus age is your exact max HR"	It is an estimate with a standard deviation of 10-12 BPM; many people are significantly above or below
"You should always train at high intensity"	Most adaptations come from easy Zone 2 training; too much intensity causes overtraining
"Heart rate monitors are always accurate"	Wrist-based optical sensors can be off by 5-10 BPM during intense exercise; chest straps are more reliable

Is the Tanaka Formula More Accurate Than 220 - Age?

Yes, for adults over 40 the Tanaka equation (Max HR = 208 - 0.7 x age) tends to be closer to measured max HR than the older Fox "220 minus age" formula. Tanaka et al. (2001, Journal of the American College of Cardiology) pooled 351 studies covering 18,712 subjects and cross-validated against 514 lab-measured subjects, reporting a correlation of r = -0.90 between age and HRmax. The American College of Sports Medicine (ACSM) now references the Tanaka equation in its Guidelines for Exercise Testing and Prescription alongside the older Fox formula.

Worked example (age 50):

• Fox formula: 220 - 50 = 170 BPM
• Tanaka formula: 208 - (0.7 x 50) = 208 - 35 = 173 BPM

The gap widens with age: at 30 the two formulas differ by just 3 BPM (190 vs 187), but at 60 the Tanaka figure (166) is 6 BPM higher than Fox (160). For under-30s the original Fox formula remains reasonable. For recreational masters athletes, Tanaka is generally the better reference point. This calculator uses 220 - age to match the formula most training plans and fitness trackers default to, but you can mentally adjust if you prefer Tanaka - the zone percentages work the same way either direction. The BMR calculator is a useful companion for balancing daily calorie burn with heart-rate-driven exercise output.

What Do the AHA Guidelines Say?

The American Heart Association defines moderate-intensity exercise as 50-70% of max HR and vigorous-intensity exercise as 70-85% of max HR. Adults should aim for 150 minutes per week of moderate-intensity activity or 75 minutes of vigorous activity, or an equivalent mix. This translates directly onto the zone chart below.

AHA Category	% Max HR	Zone on This Calculator	Weekly Target
Moderate intensity	50-70%	Zones 1-2 (Recovery + Fat Burn)	150 min/week
Vigorous intensity	70-85%	Zones 3-4 (Cardio + Threshold)	75 min/week
Combination	Mix of both	Any blend of Zones 1-4	Equivalent mix

Zone 5 (90-100% of max HR) sits above the AHA vigorous band and is reserved for trained athletes doing interval work. Most general-health benefits come from consistent time in Zones 2 and 3, not occasional all-out sessions.

Do Heart Rate Zones Change With Fitness?

Max heart rate itself barely changes with fitness - it is mostly genetic and falls roughly 1 BPM per year with age. What changes is your resting heart rate, which drops as your cardiac stroke volume improves. A sedentary adult with a resting HR of 75 who trains for a year and drops to a resting HR of 60 will see every Karvonen-based zone shift upward, even though their max HR is identical.

Scenario (Age 40, Max HR 180)	Resting HR	HRR	Zone 2 (60-70%)	Zone 4 (80-90%)
Sedentary baseline	75 BPM	105	138-149 BPM	159-170 BPM
6 months of training	65 BPM	115	134-146 BPM	157-169 BPM
Well-trained endurance	50 BPM	130	128-141 BPM	154-167 BPM

Notice the Karvonen zones shift down as resting HR falls, even though Max HR stays constant. That counter-intuitive effect is why fitter athletes often see lower absolute heart rates at the same subjective effort.

Common Mistakes That Make Zones Useless

Zones only help if the inputs are right. A few mistakes show up repeatedly in coaching conversations:

• Measuring resting HR after coffee or a poor sleep. Caffeine can raise resting HR by 5-15 BPM for 3-5 hours. A restless night can add 3-10 BPM. Always measure on a normal-sleep, pre-caffeine morning.
• Using "max HR I saw once" as a true max. A spike during an interval is usually below true max unless the effort was an all-out sustained push of 60+ seconds. If you have never done an actual max HR test, stick with a formula estimate.
• Ignoring medication effects. Beta blockers, commonly prescribed for blood pressure or arrhythmia, reduce max HR by 20-30 BPM. Zones from a formula will be meaningless if you are on one. Ask your GP for a perceived-exertion or power-based training plan instead.
• Training in Zone 3 all the time. The "grey zone" around 75-82% of max HR feels productive but is too hard to recover from daily and too easy to drive the adaptations Zones 4-5 would. Polarising your week (mostly easy, occasional hard) yields better results for most endurance goals.
• Confusing Zone 2 pace with Zone 2 heart rate. On hilly terrain your pace will swing wildly while HR stays in zone. Trust the HR.

Why Doesn't My Tracker Match This Calculator?

Wrist-worn optical heart rate sensors use photoplethysmography (PPG), which can be 5-10 BPM off during high-intensity activity, with larger errors during activities that move the wrist (weight lifting, cycling on rough terrain). Chest straps use ECG-style electrical signals and typically track within 1-2 BPM of clinical measurement. If your watch and this calculator disagree, the chest strap answer is usually closer to truth.

Other common discrepancies:

• Auto-detected max HR drift: Many fitness apps (Garmin, Polar, Apple Health) auto-update your max HR from workout peaks, which may underestimate it if you rarely push to true maximum.
• Lactate threshold HR vs max HR: Some platforms derive zones from lactate threshold HR rather than max HR, producing different absolute numbers for the same zone name.
• Stress test discrepancies: A formal graded exercise test on a treadmill or bike at a clinic remains the gold standard and will usually differ from any age-based formula by 10-20 BPM in either direction.

To pair this tool with pace-based training, the pace calculator converts between pace and speed. To estimate calories burned at different intensities, the calories burned calculator uses MET values. All calculations run in your browser with no health data stored.

Sources

• American Heart Association - Target Heart Rates Chart
• AHA - Recommendations for Physical Activity in Adults
• Tanaka H. et al. (2001) - Age-Predicted Maximal Heart Rate Revisited, JACC
• Cleary M.A. et al. - Accuracy of Age-Predicted Maximal Heart Rate Equations (PMC)
• American College of Sports Medicine - Exercise Guidelines
• NHS - Exercise and Physical Activity Benefits
• CDC - Target Heart Rate and Estimated Maximum Heart Rate