Health calculator

Free target heart rate calculator

Find your target heart rate zone in two seconds. Enter your age and resting heart rate and the calculator returns your target bpm band with the Karvonen heart-rate-reserve method, all five training zones, and the simpler percentage-of-max range — pick any intensity from recovery to maximum, updated live, as you type.

InputsLive
Intensity zone
Age
yrs
Resting heart rate
bpm
Result
Target heart rate (70%)
149 bpm
Max HR: 185 bpm · Karvonen formula
70% zone149 bpm
Max HR (220 − age)185 bpm
Resting HR65 bpm
Heart rate reserve120 bpm

Max HR estimate (220 − age) is an average. Consult a physician before changing exercise intensity, especially if you have heart conditions.

Results are estimates. Consult a professional.

Definition

What is your target heart rate?

Your target heart rate is the working range — in beats per minute — that you aim to keep your heart inside while you exercise. It is not a single number but a band: a floor you want to climb above so the session actually challenges your heart, and a ceiling you stay under so the effort is sustainable and safe. Stay below the floor and you are barely working; push past the ceiling and you cannot hold the pace. This calculator turns your age, your resting heart rate, and a chosen intensity into the exact bpm band you should see on your watch. The point of training to a target rather than to feel is repeatability: the same band on every session means easy days stay genuinely easy and hard days deliver the stimulus you intended.

Target heart rate sits well below your maximum heart rate (the all-out ceiling your heart can reach) and well above your resting heart rate (your beats per minute at complete rest). The American Heart Association frames the useful working range as 50–85% of maximum: 50–70% for moderate effort and 70–85% for vigorous effort. The calculator can express that range two ways — a plain percentage of your maximum, or the more personalised Karvonen method that also folds in your resting heart rate.

Target zone vs maximum heart rate — why they are not the same

It is easy to confuse the two. Your maximum heart rate is a fixed personal ceiling set mostly by age and genetics; you would only touch it during all-out exertion. Your target zone is where training actually happens — a deliberately chosen slice beneath that ceiling. This page is about the slice. If you only need the ceiling itself, the max heart rate calculator estimates it from age alone.

The formula

The Karvonen formula: target heart rate from heart-rate reserve

The Karvonen formula is the method this calculator leads with, because it produces a target that is personal to you rather than to everyone your age. It works from your heart-rate reserve — the gap between your maximum and resting heart rates — which is the real room your heart has to speed up. Two people the same age but with different resting rates get different targets, which is exactly right: a fitter heart should be worked differently from a sedentary one.

heart-rate reserve (HRR) = max HR resting HR
target HR = (HRR × intensity%) + resting HR
max HR ≈ 220 age

The detail that makes Karvonen different from a plain percentage is the final step: after you take a percentage of the reserve, you add your resting heart rate back in. That single addition shifts every target upward and ties it to your own physiology. It is why Karvonen targets almost always read higher than the equivalent plain-percentage targets, and why endurance athletes — who have very low resting rates — get a band that genuinely fits their training.

Zones

The five target heart rate zones

Intensity is not one setting — it is a ladder of five zones, each a defined band of your effort and each producing a different result. The table below pairs every zone with what it is for and how it feels, using the talk test (the simplest way to tell which zone you are in without a monitor). Most of your weekly training should sit in zones 2 and 3; the top zones are powerful but you can only hold them briefly.

Zone% of max / reserveBest forHow it feels (talk test)
1 · Recovery50–60%Warm-up, cool-down, active recoveryVery easy — you can sing
2 · Fat burn / base60–70%Endurance base, weight managementComfortable — full conversation
3 · Aerobic / cardio70–80%Cardio fitness, stamina, enduranceComfortably hard — short sentences
4 · Threshold80–90%Speed, power, lactate-threshold workHard — a few words at a time
5 · Maximum90–100%Short VO2-max intervals, peak effortAll-out — cannot talk

The five-zone model. Percentages apply to maximum heart rate for the plain method or to heart-rate reserve for the Karvonen method. Talk-test cues follow Cleveland Clinic and Mayo Clinic guidance.

The same five zones underpin the simpler AHA framing of 50–70% (moderate) and 70–85% (vigorous). Zones 2–3 are the moderate band most adults should live in; zones 4–5 are where trained athletes add a small amount of hard work each week.
Worked example

A worked example using the target heart rate calculator

Example: a 40-year-old with a resting heart rate of 60 bpm

Dan is 40, has measured his resting heart rate at 60 bpm, and wants the bpm band for a steady aerobic (zone 3, 70–80%) session. Here is exactly how the calculator runs the Karvonen formula, step by step.

  1. Estimate the maximum. Using 220 − age: 220 − 40 = 180 bpm. That is the ceiling the rest of the math sits under.
  2. Find the heart-rate reserve. Subtract the resting rate from the maximum: 180 − 60 = 120 bpm of reserve — the room Dan's heart has to speed up.
  3. Take the intensity band off the reserve. For 70%: 120 × 0.70 = 84. For 80%: 120 × 0.80 = 96.
  4. Add the resting rate back in. Lower bound: 84 + 60 = 144 bpm. Upper bound: 96 + 60 = 156 bpm.
Zone 3 target ≈ 144–156 bpm
Dan keeps his heart between roughly 144 and 156 bpm for an aerobic session. Notice how the resting rate carried through: the plain percentage-of-max method would have returned 126–144 bpm for the same zone — about 12–18 bpm lower — because it never adds the resting rate back in.
Two methods

Karvonen vs percentage of maximum: which should you use?

There are two honest ways to set a target, and the calculator offers both. The plain percentage-of-maximum method simply takes a percentage of your max heart rate — quick, but blind to your fitness. The Karvonen method takes the same percentage of your heart-rate reserve and adds your resting rate back, so it adapts to you. Karvonen is the better default whenever you know your resting heart rate; the plain method is the fallback when you do not.

Intensity% of max (plain)Karvonen (rest 60 bpm)
50%90 bpm120 bpm
60%108 bpm132 bpm
70%126 bpm144 bpm
80%144 bpm156 bpm
85%153 bpm162 bpm

Both columns for a 40-year-old (max HR 180 bpm); Karvonen assumes a 60 bpm resting rate. Karvonen always reads higher because the resting rate is added back in. Source: Karvonen et al., 1957; American Heart Association.

Neither method is a measured value — both rest on the age-based 220 − age estimate, which carries a ±10–12 bpm individual error. For training zones that is more than precise enough; for a medically exact figure you would need a supervised exercise (stress) test.
Myth-busting

Fat-burning zone vs cardio zone: the truth

The "fat-burning zone" (zone 2, 60–70%) earns its name honestly: at that easy intensity your body draws the highest share of its fuel from fat. The "cardio zone" (zone 3, 70–80%) is a notch harder, where the body shifts toward burning more carbohydrate. From that, gym lore concludes you should stay low and slow to lose fat. The arithmetic says otherwise.

Percentage ≠ total
The fat-burn zone burns the highest percentage of calories from fat, but higher-intensity work burns more total calories — and more total fat — per minute. For weight loss, the total energy you burn is what moves the scale, not the fuel percentage. The zone-2 label is about comfort and sustainability, not a fat-melting switch.

The practical takeaway: pick the zone that fits the session, not a myth. Long, easy zone-2 work builds an aerobic base you can do often without burning out; harder zone-3 and above burn more per minute but cost more recovery. For weight management, what matters most is total calories — pair this tool with the calories-burned calculator to see the energy each session actually costs.

Measurement

How to measure your heart rate and resting rate

The Karvonen method needs one input most people guess at: an accurate resting heart rate. Getting it right is worth a careful minute, because it shifts every target you train to.

Taking your resting heart rate

Measure it first thing in the morning, before you get out of bed, when your heart is at its true baseline. Find your pulse at your wrist (radial) or the side of your neck (carotid), count the beats for a full 60 seconds, and that is your resting rate in bpm. A typical adult sits at 60–100 bpm; well-trained endurance athletes are often 40–60 bpm. Take it across a few mornings and average them — a single reading can be thrown off by a poor night's sleep, caffeine, or stress, all of which nudge the resting rate up.

Checking your heart rate during exercise

  • Chest-strap monitor — the most accurate option for live readings; it reads the heart's electrical signal directly.
  • Wrist watch or fitness band — convenient and good enough for zone training, though optical sensors can lag or misread during sharp intensity changes.
  • Manual count — pause briefly, count your pulse for 15 seconds, and multiply by 4. Quick, but you lose a few beats as your heart rate drops the moment you stop.
If you take a beta-blocker or another medication that lowers heart rate, age-based formulas will overstate your true maximum and target. Ask your healthcare professional what your numbers should be before training by heart rate.
Definitions

Target, resting, maximum, and reserve

The working bpm range you aim for during exercise — 50–70% of maximum for moderate effort and 70–85% for vigorous, per the American Heart Association. It is the band this calculator returns.
Maximum heart rate minus resting heart rate — the room your heart has to speed up. The Karvonen method takes the intensity percentage from this reserve, not from the raw maximum.
Your beats per minute at complete rest, measured before rising in the morning. Typically 60–100 bpm for adults; 40–60 bpm for trained endurance athletes. A lower resting rate generally signals better cardiovascular fitness.
The fastest your heart can beat during all-out effort, estimated as 220 − age. It is the ceiling every target sits beneath, declines gradually with age, and is largely fixed by genetics.
A band of intensity defined as a percentage of maximum heart rate or of heart-rate reserve. The five-zone model runs from recovery (50–60%) to maximum (90–100%), each training a different adaptation.
Methodology

Sources and methodology

This calculator sets target zones with the Karvonen heart-rate-reserve method — target = (max HR − resting HR) × intensity + resting HR — first described by Karvonen, Kentala & Mustala in 1957 and recommended by the American College of Sports Medicine for exercise prescription. The maximum heart rate it builds on is the 220 − age estimate published by the American Heart Association, whose 50–85% target-zone guidance frames the moderate and vigorous bands. The plain percentage-of-maximum method is offered as the fallback when no resting rate is entered. The arithmetic is exact; the underlying age formula carries a roughly ±10–12 bpm individual error.

American Heart Association — Target Heart Rates Chart.Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate. Ann Med Exp Biol Fenn. 1957;35(3):307–315.
Questions

Frequently asked questions about the free target heart rate calculator

A target heart rate calculator is a free online tool that helps you calculate target heart rate zone using the Karvonen formula. Karvonen factors in resting HR; more individualized than %HRmax. It runs entirely in your browser with instant results and no sign-up.
Your target heart rate is the working bpm range to keep your heart inside during exercise — about 50–85% of your maximum heart rate. The American Heart Association puts moderate effort at 50–70% and vigorous effort at 70–85%.
Karvonen sets your target as (max HR − resting HR) × intensity% + resting HR. It works from your heart-rate reserve and adds your resting rate back in, so the zone is personalised to your fitness rather than just your age.
Estimate your maximum heart rate as 220 − age, then take the percentage for your chosen intensity. For a more personal figure, subtract your resting heart rate first, take the percentage of that reserve, and add your resting rate back (the Karvonen method). The calculator does both as you type.
Not on its own. The fat-burn zone (60–70%) burns the highest share of calories from fat, but higher intensities burn more total calories — and more total fat — per minute. For weight loss, total energy burned matters more than the fuel percentage.
Because Karvonen adds your resting heart rate back in after taking the intensity percentage of your reserve. That extra step lifts every target above the plain percentage-of-maximum figure — often by 12–18 bpm — and ties it to your own resting fitness.
Take it first thing in the morning before getting out of bed. Find your pulse at the wrist or neck, count the beats for a full 60 seconds, and average a few mornings. A typical adult is 60–100 bpm; trained endurance athletes are often 40–60 bpm.
About

About this target heart rate calculator

This target heart rate calculator runs entirely in your browser. Your age and resting heart rate never leave your device — nothing is sent to a server, logged, or shared. It builds your target zones with the Karvonen heart-rate-reserve method (falling back to a plain percentage of maximum when no resting rate is entered), covering all five training zones from recovery to maximum, updating instantly.

Calculators Cloud offers 400+ free tools with no sign-up. The whole Health calculators shelf includes Max heart rate, Calories burned, Pace, and VO2 max alongside this one. Or browse the full calculator directory.

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