Target Heart Rate Calculator
The short answer: Your target heart rate zones show how hard your heart should work during exercise. This calculator uses the Karvonen method: 220 minus age gives max heart rate, minus resting heart rate gives heart rate reserve, and five zones span 50 to 100 percent of that reserve. Enter your age and resting heart rate to see your zones.
What Are Heart Rate Zones?
Heart rate zones divide exercise intensity into five bands, from very light to maximum effort. Training in a specific zone produces a specific effect: lower zones build aerobic base and burn fat, middle zones improve cardiovascular fitness, and the top zones build speed and power. Without zones, most people train in a gray middle ground that is too hard for easy days and too easy for hard days.
Zones are personalized. A heart rate of 150 beats per minute might be a comfortable jog for a fit 25-year-old and an all-out effort for a sedentary 60-year-old. That is why this calculator starts from your age and your resting heart rate rather than handing you generic numbers.
How the Karvonen Method Works
The Karvonen formula, developed in the 1950s, is the most respected simple method for setting zones because it accounts for your fitness level through your resting heart rate. It works in three steps:
- Estimate max heart rate: 220 minus your age. A 40-year-old gets 180 bpm.
- Find heart rate reserve (HRR): max heart rate minus resting heart rate. With a resting rate of 65, our 40-year-old has an HRR of 115.
- Build each zone: multiply HRR by the zone percentage, then add resting heart rate back. Zone 2 (60-70%) becomes 115 x 0.60 + 65 = 134 bpm up to 115 x 0.70 + 65 = 146 bpm.
Fitter people have lower resting heart rates, which widens their reserve and shifts their zones upward. Two 40-year-olds can therefore get meaningfully different targets, which is exactly the point: the zones reflect your current fitness, not just your age. If you lift as well as train cardio, an one rep max calculator can set your strength loads while these zones govern your conditioning.
How to Use This Calculator
- Measure your resting heart rate. Take it first thing in the morning, before coffee, while still lying down. Count beats for 60 seconds, or use a wearable. Repeat for three mornings and use the average.
- Enter your age. Type your age in years. This drives the 220-minus-age max estimate.
- Enter your resting heart rate. Type the morning average in beats per minute.
- Read your zones. The table shows five zones with bpm ranges. Note your max heart rate and reserve at the top.
- Train to the zones. Do most cardio in zones 1-2, one or two harder sessions in zones 3-4, and use zone 5 sparingly for short intervals.
Example Zone Calculations
Three worked examples showing how age and resting heart rate shape the zones:
| Profile | Max HR | Zone 1 | Zone 2 | Zone 3 | Zone 4 | Zone 5 |
|---|---|---|---|---|---|---|
| Age 30, resting 60 | 190 | 125-138 | 138-151 | 151-164 | 164-177 | 177-190 |
| Age 45, resting 70 | 175 | 123-133 | 133-144 | 144-154 | 154-165 | 165-175 |
| Age 25, resting 55 | 195 | 125-139 | 139-153 | 153-167 | 167-181 | 181-195 |
Verify the first row: max HR = 220 – 30 = 190, reserve = 190 – 60 = 130. Zone 1 = 130 x 0.50 + 60 = 125 to 130 x 0.60 + 60 = 138. Zone 5 = 130 x 0.90 + 60 = 177 to 190. Notice how the 25-year-old athlete with a resting rate of 55 gets a much wider reserve (140) than the 45-year-old (105), so their zones sit higher despite the same method.
Training Tips for Each Zone
Zone 1 suits warm-ups, cool-downs and recovery walks. Zone 2 is where endurance is built: conversational pace, long sessions, the foundation runners develop with the help of a running pace calculator alongside heart rate. Zone 3 is tempo work, comfortably hard. Zone 4 is threshold training that raises the pace you can sustain. Zone 5 is short, sharp intervals with full recovery.
Two practical notes. First, heat, dehydration, caffeine, illness and poor sleep all raise heart rate, so a zone 2 run can feel like zone 3 on a hot day; a daily water intake calculator helps you stay ahead of dehydration. Second, if fat loss is the goal, pair zone 2 cardio with nutrition tracked through a calorie deficit calculator rather than chasing the old myth that only low-intensity exercise burns fat.
Frequently Asked Questions
What is a good resting heart rate?
For most adults, 60 to 100 bpm is normal, and trained endurance athletes often sit in the 40s or 50s. A lower resting rate generally signals a stronger, more efficient heart. If yours is consistently above 100 at rest, check with your doctor.
Is 220 minus age accurate for max heart rate?
It is a population average with a standard deviation of about 10 to 12 bpm, so individuals vary. More refined formulas exist, but 220 minus age remains the standard because it needs only your age and errs on the safe side for most people.
Which zone burns the most fat?
Zone 2 burns the highest percentage of calories from fat, but higher zones burn more total calories per minute. For fat loss, total energy balance matters more than the zone; steady zone 2 work plus a sensible calorie deficit beats occasional exhausting sessions.
How do I measure my resting heart rate?
Measure first thing in the morning before getting up, ideally after a restful night. Place two fingers on your wrist or neck, count beats for a full 60 seconds, and average three mornings. Wrist-based wearables work too, but confirm against a manual count once.
Can I use these zones without a heart rate monitor?
You can approximate them with perceived effort and the talk test: zone 2 allows full conversation, zone 3 allows short sentences, zone 4 allows only a few words, and zone 5 allows no talking. A monitor is more precise, but the talk test keeps you honest.
Should I train in zone 5?
Sparingly. Zone 5 intervals build top-end speed and VO2 max, but they demand long recovery and carry the highest injury and overtraining risk. One short session per week is plenty for most recreational athletes; beginners should build a zone 2 base first.
Learn More
Round out your fitness toolkit with these related calculators: