Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Heart Rate Zones Are Calculated
Heart rate zones are bands of beats per minute (bpm) that match training intensities, from easy recovery to all-out efforts. Each zone system is a set of percentages of one anchor number: your max heart rate, your heart rate reserve, or a threshold heart rate from a test. This calculator finds the anchor, then turns each percentage into a bpm range.
What Heart Rate Zones Measure
Zones show how hard you are working compared with your own limits. They do not measure fitness or calories burned. Different systems cut the range in different places, so "Zone 2" in one system is not "Zone 2" in another.
The Formula
Max HR (Tanaka) = 208 - 0.7 x age
Max HR (Fox, for comparison) = 220 - age
Zone limit by max HR = max HR x zone percent
Zone limit by heart rate reserve = resting HR + zone percent x (max HR - resting HR)
Zone limit by LTHR (Friel) = LTHR x zone percent
Tanaka's equation comes from a meta-analysis of 351 studies and 18,712 people¹.
How This Calculator Computes Your Result
Enter your age, or a max heart rate from an all-out or lab test, which is used first. The age estimate uses Tanaka's equation, rounded to a whole bpm, with Fox shown beside it. Then pick a model: 5 zones by % of max HR (default), the Norwegian 5-zone scale, 3 threshold zones, or Friel's 7 LTHR zones for running or cycling.
A resting heart rate lets you base the default zones on heart rate reserve, the Karvonen method used by the Heart Rate Reserve Calculator. The 3-zone model takes both lab threshold heart rates, or estimates them. Limits are rounded to the nearest bpm and each zone starts 1 bpm above the last, so zones never overlap. Your Zone 2 range, with 180 minus age for comparison, is shown under the table. For one moderate or vigorous range, use the Target Heart Rate Calculator.
What Your Result Means
The default model splits 50 to 100% of max HR into five equal bands. Polar and Garmin publish this split² ³, but we could not find a peer-reviewed source for it. Examples are for a max HR of 180 bpm (age 40).
Zone | Name | % of max HR | Example at 180 bpm | How it feels |
1 | Very Light | 50 to 60% | 90 to 107 | Relaxed, easy pace |
2 | Light | 60 to 70% | 108 to 125 | Conversation possible |
3 | Moderate | 70 to 80% | 126 to 143 | Talking gets harder |
4 | Hard | 80 to 90% | 144 to 161 | Fast, forceful breathing |
5 | Maximum | 90 to 100% | 162 to 180 | Sprint, labored breathing |
On heart rate reserve, the same percentages give higher numbers. With a resting heart rate of 60, Zone 1 starts at 120 bpm and Zone 2 is 132 to 143 bpm.
The Norwegian scale is used across endurance sports in Norway and was built mainly from testing skiers, biathletes and rowers⁴. Sport scientists also use 3 zones, set by two lab thresholds: below the first ventilatory threshold (VT1), between the two, and above the second (VT2)⁵. Norwegian Zone 3 lines up with 3-zone Zone 2⁴, so without a test this calculator places VT1 at 85% and VT2 at 90% of max HR.
Norwegian zone | % of max HR | Example at 180 bpm | Blood lactate (mmol/L) | 3-zone model |
1 | 55 to 75% | 99 to 134 | 0.8 to 1.5 | Zone 1 |
2 | 75 to 85% | 135 to 152 | 1.5 to 2.5 | Zone 1 |
3 | 85 to 90% | 153 to 161 | 2.5 to 4 | Zone 2 |
4 | 90 to 95% | 162 to 170 | 4 to 6 | Zone 3 |
5 | 95 to 100% | 171 to 180 | 6 to 10 | Zone 3 |
Friel's LTHR is your average heart rate over the last 20 minutes of a 30-minute solo time trial at race effort⁶.
Zone | Running (% of LTHR) | Cycling (% of LTHR) | Example, running LTHR 165 |
1 | Under 85% | Under 81% | Up to 139 |
2 | 85 to 89% | 81 to 89% | 140 to 148 |
3 | 90 to 94% | 90 to 93% | 149 to 156 |
4 | 95 to 99% | 94 to 99% | 157 to 164 |
5a | 100 to 102% | 100 to 102% | 165 to 169 |
5b | 103 to 106% | 103 to 106% | 170 to 175 |
5c | Over 106% | Over 106% | 176 and up |
Zone 2 Heart Rate: What It Is and What the Evidence Says
A panel of 14 sport scientists and coaches defined Zone 2 training as exercise just below the first lactate or ventilatory threshold⁷. In the 3-zone model that is the top of Zone 1, because its Zone 2 is the harder band between thresholds⁵. For a 40-year-old with a max HR of 180, "Zone 2" varies a lot:
Model | Zone 2 | Example |
5 zones, % of max HR | 60 to 70% of max | 108 to 125 bpm |
Norwegian scale | 75 to 85% of max | 135 to 152 bpm |
3-zone model | Between VT1 and VT2 | 153 to 161 bpm, estimated |
Friel, running | 85 to 89% of LTHR | 140 to 148 bpm at LTHR 165 |
Most of the evidence comes from how top athletes train. Elite endurance athletes do about 80% of their sessions at low intensity⁸, and junior skiers tracked for 32 days did about 75% of endurance sessions in 3-zone Zone 1 and 8% in Zone 2⁵. Professional cyclists burned more fat and had lower blood lactate during exercise than less fit people⁹. That was a one-time comparison of groups, so it does not show that Zone 2 training causes the difference, and the expert panel said the gains may not be unique to Zone 2⁷.
For a free check, recite a paragraph of 30 to 100 words and ask, "Can I speak comfortably?" The point where talking first gets harder sits near your first threshold¹⁰, so Zone 2 is just on the easy side of it.
Phil Maffetone's 180 minus age rule gives 140 bpm at age 40, before his adjustments of minus 10 to plus 5. He built it from his own athlete assessments and says it "is not associated with VO2max, lactate threshold, or other traditional measurements"¹¹. Treat it as a rule of thumb.
How Accurate Is an Age-Based Max Heart Rate?
The 220 minus age formula traces back to a rough line fitted by eye to data compiled in 1971, and two decades of studies found errors of about 7 to 11 bpm¹². Tanaka found it also reads too low in older adults¹. Fox and Tanaka match at age 40; Fox is higher below 40 and lower above. In 3,320 healthy adults, the best age formula still had a standard error of 10.8 bpm¹³. A measured max HR or threshold test gives more personal zones.
Heart Rate Zones by Age
The default five zones (50 to 100% of max heart rate) for each age, using the Tanaka estimate of max heart rate.
- Zone 1 Very Light
- Zone 2 Light
- Zone 3 Moderate
- Zone 4 Hard
- Zone 5 Maximum
Show data table
| Age | Zone 1 Very Light | Zone 2 Light | Zone 3 Moderate | Zone 4 Hard | Zone 5 Maximum |
|---|---|---|---|---|---|
| Age 20 (max 194) | 97 to 115 bpm | 116 to 135 bpm | 136 to 154 bpm | 155 to 174 bpm | 175 to 194 bpm |
| Age 25 (max 191) | 96 to 114 bpm | 115 to 133 bpm | 134 to 152 bpm | 153 to 171 bpm | 172 to 191 bpm |
| Age 30 (max 187) | 94 to 111 bpm | 112 to 130 bpm | 131 to 149 bpm | 150 to 167 bpm | 168 to 187 bpm |
| Age 35 (max 184) | 92 to 109 bpm | 110 to 128 bpm | 129 to 146 bpm | 147 to 165 bpm | 166 to 184 bpm |
| Age 40 (max 180) | 90 to 107 bpm | 108 to 125 bpm | 126 to 143 bpm | 144 to 161 bpm | 162 to 180 bpm |
| Age 45 (max 177) | 89 to 105 bpm | 106 to 123 bpm | 124 to 141 bpm | 142 to 158 bpm | 159 to 177 bpm |
| Age 50 (max 173) | 87 to 103 bpm | 104 to 120 bpm | 121 to 137 bpm | 138 to 155 bpm | 156 to 173 bpm |
| Age 55 (max 170) | 85 to 101 bpm | 102 to 118 bpm | 119 to 135 bpm | 136 to 152 bpm | 153 to 170 bpm |
| Age 60 (max 166) | 83 to 99 bpm | 100 to 115 bpm | 116 to 132 bpm | 133 to 148 bpm | 149 to 166 bpm |
| Age 65 (max 163) | 82 to 97 bpm | 98 to 113 bpm | 114 to 129 bpm | 130 to 146 bpm | 147 to 163 bpm |
| Age 70 (max 159) | 80 to 94 bpm | 95 to 110 bpm | 111 to 126 bpm | 127 to 142 bpm | 143 to 159 bpm |
| Age 75 (max 156) | 78 to 93 bpm | 94 to 108 bpm | 109 to 124 bpm | 125 to 139 bpm | 140 to 156 bpm |
| Age 80 (max 152) | 76 to 90 bpm | 91 to 105 bpm | 106 to 121 bpm | 122 to 136 bpm | 137 to 152 bpm |
A Note on Accuracy
These zones are training estimates, not a medical test. Age formulas can miss your true max by 10 bpm or more, and the 3-zone estimate uses an athlete-based scale. Some medicines lower heart rate, so if you have a heart condition or take medication, ask your doctor what range fits you¹⁴.
Frequently Asked Questions
What are the 5 heart rate zones?
In the split most watches use, Zone 1 is 50 to 60% of max heart rate, Zone 2 is 60 to 70%, Zone 3 is 70 to 80%, Zone 4 is 80 to 90% and Zone 5 is 90 to 100%² ³.
How do I calculate my zone 2 heart rate?
With watch-style zones, Zone 2 runs from 60% of your max heart rate to just below 70%. Sport scientists place Zone 2 just below your first lactate threshold⁷, so a talk test or lab test is the best check¹⁰.
Is 180 minus age accurate for zone 2?
It is a rule of thumb, not a tested threshold. Its creator says the number is not tied to VO2 max or lactate threshold¹¹.
How accurate is a heart rate zone calculator?
It is only as accurate as the max heart rate or threshold behind it, and age formulas typically miss by about 7 to 11 bpm¹² ¹³.
Sources
Age-Predicted Maximal Heart Rate Revisited, Tanaka et al., 2001
Heart Rate Zones, Polar
Heart Rate Zone Calculations, Garmin
Intervals, Thresholds, and Long Slow Distance, Seiler and Tønnessen, 2009
Quantifying Training Intensity Distribution in Elite Endurance Athletes, Seiler and Kjerland, 2006
Joe Friel's Quick Guide to Setting Zones, Friel, 2012
What Is Zone 2 Training?, Sitko et al., 2025
Best Practice for Training Intensity and Duration Distribution, Seiler, 2010
Assessment of Metabolic Flexibility, San-Millán and Brooks, 2018
The Talk Test, Foster et al., 2018
The MAF 180 Formula, Maffetone
The Surprising History of the HRmax=220-age Equation, Robergs and Landwehr, 2002
Age-Predicted Maximal Heart Rate in Healthy Subjects, Nes et al., 2013
Target Heart Rates Chart, American Heart Association