BYTETOOLS

Target Heart Rate Calculator

Calculate your target heart rate zones with the Karvonen reserve method and the percent-of-maximum method, from an estimated or measured maximum heart rate.

Target heart rate — Karvonen reserve method

142 – 166 bpm

(184 − 65) × 0.65 + 65 = 142bpm  ·  (184 − 65) × 0.85 + 65 = 166 bpm

The simple percent-of-maximum method gives 119–156 bpm for the same percentages. Karvonen is usually the more useful of the two because it accounts for your resting heart rate, so a fitter person with a low resting pulse gets a wider, lower-anchored range.

184 bpm
Estimated max HR
65 bpm
Resting HR
119 bpm
Heart-rate reserve
142–166
Target range

All five training zones

ZoneIntensityKarvonen (bpm)% of max (bpm)What it is for
Zone 1 — Recovery50–60%124–13692–110Warm-up, cool-down, easy recovery days
Zone 2 — Endurance60–70%136–148110–128Long conversational efforts; builds the aerobic base
Zone 3 — Aerobic70–80%148–160128–147Steady tempo work; talking becomes clipped
Zone 4 — Threshold80–90%160–172147–165Hard intervals at or near lactate threshold
Zone 5 — Maximum90–100%172–184165–184Short all-out repeats; only sustainable for minutes

Tanaka: 208 − 0.7 × 35 = 184 bpm

These are training estimates only, not medical advice and not a diagnosis of anything. Age-predicted maximum heart rate is a population average with a standard deviation of roughly 10–12 bpm, so your true maximum can easily be 20 bpm above or below the number shown, and beta blockers and other medications lower it further. If you have a heart condition, high blood pressure, chest pain, or you are returning to exercise after a long break, agree your training intensities with a clinician before using them.

What is the Target Heart Rate Calculator?

A target heart rate calculator uses the Karvonen formula — ((maximum HR − resting HR) × intensity) + resting HR — to turn a training intensity percentage into an actual beats-per-minute range for your own heart.

  • Karvonen heart-rate reserve method alongside percent-of-maximum
  • Four maximum heart rate options: Fox, Tanaka, Gulati or measured
  • All five training zones from recovery to maximal, with their purpose
  • Shows the calculation so the numbers are auditable
  • Warns when resting heart rate leaves no usable reserve
  • Runs offline in your browser — nothing is uploaded

How to use the Target Heart Rate Calculator

  1. 1

    Enter your age and your resting heart rate, measured sitting still.

  2. 2

    Choose which maximum heart rate formula to use, or enter a measured maximum.

  3. 3

    Set the lower and upper intensity percentages you want to train between.

  4. 4

    Read your Karvonen target range and compare it against the percent-of-max range.

  5. 5

    Use the five-zone table to pick the right range for each type of session.

About the Target Heart Rate Calculator

The ByteTools Target Heart Rate Calculator works out the beats-per-minute range you should be training in. It uses the Karvonen heart-rate reserve method, ((HRmax − HRrest) × intensity) + HRrest, and shows the simpler percent-of-maximum figures side by side so you can see how much difference the method makes.

Pick where your maximum heart rate comes from: the classic Fox equation (220 − age), the more accurate Tanaka equation (208 − 0.7 × age), the Gulati equation derived specifically from women (206 − 0.88 × age), or a maximum you have actually measured. Then set your intensity range and read all five training zones, from recovery through to maximal effort, with a note on what each one is for.

Nothing is uploaded — the calculation runs entirely in your browser and your age and heart rate stay on your device. These are training estimates only and are not medical advice or a diagnosis. Age-predicted maximum heart rate has a standard deviation of roughly 10–12 bpm, and medication such as beta blockers lowers it further, so clear your training intensities with a clinician if you have any cardiovascular concern.

Frequently asked questions

What is the Karvonen formula?

Karvonen calculates a target heart rate as ((maximum HR − resting HR) × intensity) + resting HR. The bracketed part is your heart-rate reserve — the working range between rest and maximum. For a 40-year-old with a 180 bpm maximum and a 60 bpm resting rate, 65% intensity gives (180 − 60) × 0.65 + 60 = 138 bpm.

Is Karvonen better than 220 minus your age?

They answer slightly different questions. 220 − age only estimates your maximum; Karvonen then anchors the intensity range to your resting heart rate as well, so a fitter person with a low resting pulse gets a different range from someone with the same maximum but a high resting pulse. Karvonen is generally the more useful of the two for prescribing training.

How accurate is an age-predicted maximum heart rate?

As a population average it is fine; as a personal number it is rough. Both 220 − age and the Tanaka equation carry a standard deviation of around 10 to 12 bpm, meaning roughly one person in three has a true maximum more than 10 bpm away from the prediction, and one in twenty is more than 20 bpm out. A measured maximum from a supervised test is far better if the exact number matters.

What is a good target heart rate for fat burning?

The so-called fat-burning zone sits around 60 to 70 percent, where a larger share of the calories burned comes from fat. But higher intensities burn more calories in total, and total energy balance is what actually drives fat loss, so the zone is more useful as a way to describe an easy sustainable effort than as a weight-loss strategy.

Why is my resting heart rate important?

It is your floor. Karvonen builds the whole target range up from it, so a resting rate that is 15 bpm too high shifts every zone upward. Measure it sitting or lying still, ideally before you get out of bed, and count for a full minute rather than extrapolating from fifteen seconds.

Does medication affect these zones?

Yes, substantially. Beta blockers and some other cardiac medications lower both resting and maximum heart rate, which makes age-predicted formulas meaningless. If you take them, ask your doctor or a cardiac rehabilitation team for training targets rather than using a calculator.

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