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Target Heart Rate Calculator

Find your ideal training heart-rate zone with the Karvonen formula.

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How to use

  1. 1.Enter your age in years so the tool can estimate your maximum heart rate as 220 - age.
  2. 2.Enter your resting heart rate in bpm, ideally measured first thing in the morning before getting up.
  3. 3.Enter your target intensity as a percentage (for example 70) to read your target heart rate and the 50%-85% training zone instantly.

About Target Heart Rate Calculator

The target heart rate calculator tells you the exact beats-per-minute range to aim for during exercise, so you train hard enough to improve fitness without overdoing it. It uses the Karvonen formula, also called the heart-rate reserve (HRR) method, which is more personalized than the simple percentage-of-maximum approach because it accounts for how fit you already are through your resting heart rate.

First it estimates your maximum heart rate from your age with the widely used Fox equation, HRmax = 220 - age. Your heart-rate reserve is the gap between that maximum and your resting heart rate, HRR = HRmax - resting HR. The target heart rate for any intensity is then Target = (HRR x intensity%) + resting HR. Because the resting heart rate is added back in, two people of the same age but different fitness levels get different targets, which is exactly the point. A trained runner with a resting pulse of 48 and a sedentary person of the same age with a resting pulse of 75 will see clearly different target numbers even at the identical intensity percentage.

Enter three numbers and the result updates instantly: your age in years, your resting heart rate in bpm (measured when you first wake up, before getting out of bed), and your desired intensity as a percentage. The tool shows the single target bpm for that intensity plus a broader moderate-to-vigorous training zone spanning 50% to 85% of your reserve, which covers most cardio, fat-burning and endurance work. A worked example: for a 30-year-old with a resting heart rate of 60, HRmax is 190, the reserve is 130, and 70% intensity gives a target of 151 bpm.

As a rough guide, roughly 50-70% intensity is moderate aerobic exercise (brisk walking, easy cycling) and about 70-85% is vigorous (running, intervals). Below 50% you build a base and recover; pushing above 85% edges toward anaerobic effort that is hard to sustain. Beginners usually start at the lower end and build up over several weeks as their resting heart rate gradually falls and the same effort feels easier. Measuring resting heart rate accurately matters: take your pulse for 60 seconds first thing in the morning across several days and average the readings, since caffeine, stress, dehydration and poor sleep all push it up.

There are other ways to gauge effort that complement these numbers. The talk test is a simple field check - at moderate intensity you can hold a conversation, while at vigorous intensity you can only manage short phrases. Rating of perceived exertion (RPE) on a 1-to-10 scale is another quick cross-reference when you do not have a heart-rate monitor handy. Using perceived effort alongside the calculated zone helps catch days when illness, heat or fatigue shift your real response away from the average.

Everything is calculated locally in your browser, so nothing you type is uploaded. The 220 - age formula is a population average and can be off by 10-12 bpm for any individual, so treat these numbers as a starting estimate rather than a precise limit. This is a general fitness tool, not medical advice - if you have a heart condition, take medication that affects heart rate such as beta blockers, or are new to exercise, talk to a doctor before using these targets.

Methodology & sources

Target heart rate is computed with the Karvonen formula (heart-rate reserve method): Target = (HRmax - restingHR) x intensity% + restingHR, where HRmax = 220 - age (Fox age-prediction equation). The displayed zone spans 50% (moderate) to 85% (vigorous) of heart-rate reserve. Assumptions: 220 - age is a population average that can vary by roughly 10-12 bpm per individual, and resting heart rate is assumed to be measured accurately at rest. This is a general fitness estimate, not medical advice; consult a doctor before starting exercise, especially with heart conditions or heart-rate-affecting medication.

Frequently asked questions

What is the Karvonen formula?
The Karvonen formula, or heart-rate reserve method, calculates a target heart rate as (max HR - resting HR) x intensity% + resting HR. It is more personalized than a plain percentage of maximum heart rate because it factors in your resting heart rate, which reflects your current fitness.
How do I measure my resting heart rate?
Measure it when you are fully rested, ideally right after waking up and before getting out of bed. Count your pulse for a full 60 seconds, repeat on a few different mornings, and use the average. Caffeine, stress, illness and poor sleep can all raise it.
What intensity should I train at?
Roughly 50-70% of your heart-rate reserve is moderate aerobic exercise and about 70-85% is vigorous. Beginners typically start near the lower end and progress upward. The tool also shows the full 50%-85% moderate-to-vigorous zone for reference.
Is 220 minus age an accurate maximum heart rate?
It is a widely used population average but can be off by about 10-12 bpm for any given person. Treat the results as a helpful estimate, not an exact ceiling. For a precise figure, a supervised exercise test is needed.

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