Heart Rate Calculator

Maximum heart rate equals 220 minus age
years

Solution

—
Share:

Maximum Heart Rate (Common Formula)

The most widely used estimate of maximum heart rate. Simple and quick but has a standard deviation of about ±12 bpm. Alternative formulas (Inbar, Londeree, Miller) may be more accurate for specific populations.

HR_max = 220 − age

Heart Rate Reserve

Heart rate reserve is the difference between your maximum and resting heart rates. It represents your usable training range and is the foundation of the Karvonen method for setting target heart rate zones.

HR_reserve = HR_max − HR_rest

Target Heart Rate (Karvonen Method)

The Karvonen method uses heart rate reserve to set personalized target zones for each exercise intensity. It accounts for resting heart rate, giving more accurate zones than simple percentage of max HR.

THR = (HR_max − HR_rest) × intensity + HR_rest

How It Works

This calculator estimates three key heart-rate metrics. Maximum heart rate (HR_max) is the fastest your heart can beat during all-out effort. Heart rate reserve is the difference between max and resting rates, representing your usable training range. The Karvonen method then uses that reserve to set personalized target zones for each exercise intensity.

Example Problem

A 30-year-old with a resting heart rate of 65 bpm wants to find their 70% Karvonen target.

  1. Identify the knowns. Age = 30 years, resting heart rate HR_rest = 65 bpm (measured first thing in the morning), and desired training intensity = 70% of heart rate reserve.
  2. Identify what we're solving for. We want the target heart rate (THR) for a 70% Karvonen aerobic-training zone — the bpm to sustain during the workout.
  3. Estimate maximum heart rate using the common formula: HR_max = 220 − age = 220 − 30 = **190 bpm**. Keep in mind this estimate has a standard deviation of about ±12 bpm.
  4. Calculate heart rate reserve (HRR): HR_reserve = HR_max − HR_rest = 190 − 65 = **125 bpm**. This is the usable training range above the resting baseline.
  5. Write the Karvonen formula: THR = (HR_max − HR_rest) × intensity + HR_rest. Substitute the known values: THR = 125 × 0.70 + 65.
  6. Compute the target: THR = 87.5 + 65 = **152.5 bpm** — the bpm to hold during a 70% aerobic effort, which is typical for endurance base-building and tempo runs.

When to Use Each Variable

  • Solve for Max HR (Common) — when you need a quick estimate using 220 minus age, e.g., setting up a basic training zone chart.
  • Solve for Max HR (Inbar) — when you want a research-based alternative formula, e.g., comparing estimates for older or highly fit populations.
  • Solve for HR Reserve — when you know your max and resting heart rates, e.g., finding the range available for training intensity.
  • Solve for Target HR (Karvonen) — when you want personalized training zones that account for resting heart rate, e.g., setting a 70% intensity target for aerobic training.

Key Concepts

Maximum heart rate is the fastest your heart can beat during all-out exertion and decreases with age. Heart rate reserve (HRR) is the difference between max and resting heart rates — it represents the usable training range. The Karvonen method multiplies HRR by a target intensity percentage and adds back the resting heart rate, producing more personalized zones than simple percentage-of-max methods.

Applications

  • Endurance training: setting target heart rate zones for aerobic base building, tempo runs, and interval workouts
  • Cardiac rehabilitation: prescribing safe exercise intensities for patients recovering from heart events
  • Fitness assessment: using resting heart rate trends to track cardiovascular fitness improvements over time
  • Wearable technology: calibrating heart rate monitors and smartwatches for accurate zone alerts

Common Mistakes

  • Treating 220 minus age as exact — it has a standard deviation of ±12 bpm and may be off significantly for individuals
  • Using simple percentage of max HR instead of the Karvonen method — simple percentage ignores resting heart rate and underestimates actual intensity
  • Not measuring resting heart rate correctly — it should be taken first thing in the morning before getting out of bed
  • Applying the same max HR formula to all populations — older adults, women, and highly trained athletes may benefit from alternative formulas like Inbar or Londeree

Frequently Asked Questions

How accurate is the 220 minus age formula?

The 220 minus age formula is a rough estimate with a standard deviation of about ±12 bpm. Alternative formulas (Inbar, Londeree, Miller) may be more accurate for specific populations, but a clinical graded exercise test is the only precise way to measure max HR. Output here is informational only and not a substitute for clinical judgment.

What is a good resting heart rate?

A normal resting heart rate for adults is 60–100 bpm. Well-trained endurance athletes may have resting rates as low as 40–50 bpm, while sedentary adults often sit in the 70–80 bpm range. A consistently lower resting rate generally indicates better cardiovascular fitness, but persistent bradycardia (< 50 bpm) in a non-athlete should be discussed with a clinician.

What heart rate zone burns the most fat?

The so-called fat-burning zone is roughly 60–70% of max HR (or HRR by Karvonen). At lower intensities a higher percentage of calories come from fat, but higher-intensity exercise burns more total calories &mdash; and more total fat per session &mdash; in a given time window. For body-composition goals, total calorie burn matters more than the fat fraction.

Why use the Karvonen method instead of simple percentage of max HR?

The Karvonen method (also called the heart rate reserve method) accounts for resting heart rate, giving a more personalized zone than %HRmax alone. Two people with the same max HR but different resting rates will get different target zones, reflecting their individual fitness levels. Karvonen is the standard prescription method in cardiac rehabilitation and most exercise-physiology textbooks.

How do I correctly measure resting heart rate?

Measure first thing in the morning, before getting out of bed, ideally for 3–5 consecutive days and average the results. Avoid measurement after caffeine, alcohol, illness, or poor sleep, which can elevate resting HR by 10–15 bpm. A wrist-based wearable in sleep mode is acceptable; a 60-second manual pulse count at the radial artery is the gold standard.

Which max heart rate formula should I use?

The 220 − age formula is most widely cited but tends to overestimate HRmax in adults over 40. Tanaka (208 − 0.7 × age) and Inbar (205.8 − 0.685 × age) typically fit older or fitter populations better. For untrained adults over 60 or anyone in cardiac rehab, a clinician-supervised stress test is preferred over any formula.

Is it dangerous to exceed my estimated max heart rate?

Hitting or briefly exceeding an estimated HRmax during all-out effort is usually not dangerous in healthy adults &mdash; the estimate is just the population mean for your age, with a ±12 bpm standard deviation. However, anyone with known heart disease, recent symptoms (chest pain, dizziness, palpitations), or risk factors should establish a safe ceiling with a clinician before training near max effort. Informational only; not a substitute for medical advice.

Worked Examples

Endurance Training

What's a 35-year-old marathoner's zone-2 target at HRmax 185, resting HR 50?

An experienced runner has measured a true treadmill max of 185 bpm and a resting heart rate of 50 bpm. Zone 2 (aerobic base) sits around 70% of heart rate reserve under the Karvonen method — the bread-and-butter intensity for long aerobic builds.

  • HRmax = 185 bpm
  • HRrest = 50 bpm
  • Intensity = 70% = 0.70
  • THR = (HRmax − HRrest) × intensity + HRrest
  • THR = (185 − 50) × 0.70 + 50 = 135 × 0.70 + 50
  • THR = 94.5 + 50

Target HR ≈ 145 bpm (70% Karvonen, zone 2)

Karvonen scales intensity over the heart rate reserve (HRR) rather than HRmax alone, so it adapts to your conditioning — a low resting HR raises every zone above what a percent-of-HRmax method would give. Informational only; not a substitute for clinical advice or a personalized training prescription from a coach or cardiologist.

Clinical Cardiology

What does the Inbar formula predict for a 68-year-old cardiac patient's HRmax?

Older athletes and cardiac-rehab patients are typically given an age-adjusted HRmax — the 220 − age rule overestimates max heart rate in this group by 10–15 bpm. The Inbar formula (HRmax = 205.8 − 0.685 × age) is one of the better-fitting alternatives in patients over 60.

  • age = 68 years
  • HRmax = 205.8 − 0.685 × age
  • HRmax = 205.8 − 0.685 × 68
  • HRmax = 205.8 − 46.58

HRmax ≈ 159 bpm (Inbar)

Comparing four formulas at this age: Common 220 − 68 = 152 bpm, Inbar 159, Londeree 158, Miller 159. Cardiologists generally favor a measured graded-exercise test over any formula for prescribing rehab targets. Informational only; not a substitute for clinical judgment.

Postpartum Fitness

What target HR fits a postpartum return-to-running plan at HRmax 187, resting HR 72?

A 33-year-old runner six months postpartum has an elevated resting HR of 72 (still recovering) and an estimated HRmax of 187 bpm. ACOG-aligned guidance is to start return-to-running at moderate intensity (around 60% HRR) and progress only after each session feels easy.

  • HRmax = 187 bpm
  • HRrest = 72 bpm
  • HRR = 187 − 72 = 115 bpm
  • Intensity = 60% = 0.60 (moderate)
  • THR = (HRmax − HRrest) × intensity + HRrest
  • THR = 115 × 0.60 + 72 = 69 + 72

Target HR ≈ 141 bpm (60% Karvonen)

The result table shows every 5% band from 50–100% — read the 60% row to confirm against this hand calc, then watch the 70% row drift down as resting HR drops over the next months of training. Informational only; not a substitute for clinical advice — clear postpartum exercise with your physician or pelvic-floor PT first.

Heart Rate Formulas

This calculator uses four published maximum heart rate (HRmax) estimators plus the heart rate reserve and Karvonen target-zone equations:

Max Heart Rate
HRmax = 220 − ageCommon (Fox & Haskell 1971)
HRmax = 205.8 − 0.685 × ageInbar (better fit for older or fit adults)
HRmax = 206.3 − 0.711 × ageLonderee & Moeschberger
HRmax = 217 − 0.85 × ageMiller (alternative regression)
Reserve & Target Zone
HRR = HRmax − HRrestHeart rate reserve (usable training range)
THR = (HRmax − HRrest) × intensity + HRrestKarvonen target heart rate

Where:

  • HRmax — maximum heart rate (beats per minute, bpm)
  • HRrest — resting heart rate, measured first thing in the morning (bpm)
  • HRR — heart rate reserve (bpm)
  • age — chronological age (years)
  • intensity — training intensity as a decimal fraction of HRR (e.g., 0.70 for 70% Karvonen)
  • THR — target heart rate for the workout (bpm)

All HRmax formulas are population-mean regressions with a standard deviation of roughly ±10–12 bpm. The Karvonen (heart rate reserve) method is generally preferred over simple %HRmax because it scales the target zone against an individual's resting heart rate, giving more accurate prescriptions for trained athletes and cardiac patients. Output here is informational only and is not a substitute for clinical judgment or a personalized exercise prescription.

Related Calculators

Related Sites