# What’s my target heart rate?

Works out the CDC target heart rate zones for moderate (64% to 76%) and vigorous (77% to 93%) exercise from the age-predicted maximum heart rate, and where a measured heart rate falls.

- Page: https://www.acalculator.org/health/target-heart-rate-calculator
- JSON spec: https://www.acalculator.org/health/target-heart-rate-calculator.json
- Version: 4ca84f4e8970

## Default answer

Example with the default inputs (Age 50, Exercise intensity Moderate, Maximum heart rate formula 220 − age, Heart rate to check 120): Moderate intensity at age 50: keep your heart rate at 109 to 129 bpm.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| age | Age | Your age in whole years. |
| intensity | Exercise intensity | Moderate is 64% to 76% of the maximum heart rate; vigorous is 77% to 93% (CDC). |
| formula | Maximum heart rate formula | How the maximum heart rate is estimated from age: 220 − age (CDC) or 208 − 0.7 × age (Tanaka). |
| hr | Heart rate to check | A heart rate measured during exercise, in beats per minute, to see which zone it is in. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| zone | Target heart rate | The target zone for the chosen intensity, in whole beats per minute. |
| low | Zone starts at | The lower end of the chosen zone in beats per minute: the lower share × the maximum. |
| high | Zone ends at | The upper end of the chosen zone in beats per minute: the upper share × the maximum. |
| max | Estimated max heart rate | The age-predicted maximum heart rate in beats per minute. |
| pct | Checked heart rate, % of max | The heart rate to check as a percent of the estimated maximum, with its intensity band. |

## Method

Maximum heart rate = 220 − age (or 208 − 0.7 × age); moderate zone = 64% to 76% of the maximum; vigorous zone = 77% to 93% (CDC). A checked heart rate is light below 64%, moderate from 64% to under 77%, vigorous from 77% to under 100%.

## Assumptions

- The maximum heart rate is estimated from age alone; a person’s measured maximum can differ by 10 beats per minute or more.
- The zones are the CDC’s percentages of the maximum heart rate, taken from the ACSM exercise guidelines.
- A checked heart rate is light below 64% of the maximum, moderate from 64% to under 77%, and vigorous from 77% up to the maximum.
- This is for information only and is not medical advice. Heart-rate medicines such as beta blockers change the response to exercise.

## Worked examples

1. age = 50, intensity = moderate, formula = fox gives max = 170, low = 108.8, high = 129.2, zone = 109 to 129 bpm. Source: CDC, Target Heart Rate and Estimated Maximum Heart Rate: age 50, 170 × 0.64 = 109 bpm and 170 × 0.76 = 129 bpm.
2. age = 35, intensity = vigorous, formula = fox gives max = 185, low = 142.45, high = 172.05, zone = 142 to 172 bpm. Source: CDC, Target Heart Rate and Estimated Maximum Heart Rate: age 35, 185 × 0.77 = 142 bpm and 185 × 0.93 = 172 bpm.
3. age = 40, intensity = moderate, formula = tanaka, hr = 150 gives max = 180, low = 115.2, high = 136.8, zone = 115 to 137 bpm, pct = 83.333333%. Source: hand calculation in content.mdx: Tanaka 2001, 208 − 0.7 × 40 = 180; CDC shares 0.64 and 0.76; 150 ÷ 180 = 83.3%, in the vigorous range.
4. age = 50, intensity = moderate, formula = fox, hr = 120 gives pct = 70.588235%. Source: hand calculation in content.mdx: 120 ÷ (220 − 50) = 70.6%, in the CDC moderate range (64% to 76%).

## FAQ

### How do I calculate my target heart rate?

Estimate your maximum heart rate as 220 − your age, then take a share of it. For moderate exercise, the CDC uses 64% to 76% of the maximum; for vigorous exercise, 77% to 93%. At age 50: the maximum is 170, so the moderate zone is 170 × 0.64 = 109 to 170 × 0.76 = 129 beats per minute.

### What is the difference between moderate and vigorous exercise?

Moderate exercise, such as brisk walking, raises your heart rate to about 64% to 76% of your maximum. You can talk but not sing. Vigorous exercise, such as running, raises it to about 77% to 93%. You can say only a few words without stopping for breath.

### How do I check my heart rate during exercise?

Stop briefly and find your pulse at the wrist, in line with the thumb. Press lightly with the tips of your index and middle fingers, not your thumb. Count the beats for 60 seconds, or count for 30 seconds and double it. A heart rate monitor or watch also works.

### Why does the calculator offer 208 − 0.7 × age?

Tanaka and others (2001) combined 351 studies and found that 220 − age underestimates the maximum heart rate of older adults. Their equation, 208 − 0.7 × age, gives the same value at age 40 and higher values after it. At age 60, it gives 166 instead of 160.

### What is the heart rate reserve (Karvonen) method?

Karvonen (1957) set the target as resting heart rate + a share × (maximum − resting heart rate). It uses different shares from the ones on this page, so the numbers are not interchangeable. This calculator uses the CDC's shares of the maximum heart rate, which need only your age.

### Is it safe to exercise at my target heart rate?

The zones are general guidance for healthy adults. If you have a heart condition, take medicines that change your heart rate (such as beta blockers), are pregnant, or are new to exercise, ask a health care professional which intensity is right for you.

## Sources

- Centers for Disease Control and Prevention, How to Measure Physical Activity Intensity (last reviewed December 4, 2025). https://www.cdc.gov/physical-activity-basics/measuring/index.html
- Centers for Disease Control and Prevention, Target Heart Rate and Estimated Maximum Heart Rate (last reviewed June 3, 2022; no longer on cdc.gov; archived copy). http://web.archive.org/web/20221225180518/https://www.cdc.gov/physicalactivity/basics/measuring/heartrate.htm
- Riebe D, Ehrman JK, Liguori G, Magal M. ACSM's Guidelines for Exercise Testing and Prescription, 10th edition, chapter 6. Wolters Kluwer, 2018 (the source of the CDC percentages).
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology 2001;37:153–156. doi:10.1016/s0735-1097(00)01054-8
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae 1957;35:307–315.