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Target Heart Rate Calculator

Fitness & Health

Calculate your target heart rate zones for exercise using the Karvonen (Heart Rate Reserve) or percentage of max HR method. Get your maximum heart rate, all 5 training zones with exact bpm ranges, a custom target HR for any intensity, resting HR classification, and science-backed tips for smarter training.

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Explore This Tool in Context

Target Heart Rate Calculator is part of the Fitness & Health collection. If you want a broader view of similar workflows, open the Fitness & Health category page or browse all QuickTools categories.

Common next steps after this tool include BMI Calculator, Calorie Calculator and Body Fat Calculator.

How to Use the Target Heart Rate Calculator

1

Enter Your Age

Age is the primary input — it determines your estimated maximum heart rate using the Tanaka or Fox formula.

2

Add Resting HR (optional)

Measure your resting heart rate first thing in the morning before getting out of bed. Entering it enables the more accurate Karvonen method.

3

Override Max HR (optional)

If you have measured your actual maximum heart rate during a lab test or field test, enter it here to override the formula estimate.

4

Set a Custom Target %

Use the slider to set any target intensity from 50–100%. The calculator will show the exact bpm and which zone that falls in.

5

Choose Formula & Method

Select Tanaka (more accurate for adults 40+) or Fox (220 − age, the classic). Choose Karvonen for precise zones or % of Max HR for simplicity.

6

Read Your Zones

All 5 heart rate zones are displayed with exact bpm ranges, the % of max HR, training benefits, and your custom target zone highlighted.

What Is Target Heart Rate?

Your target heart rate (THR) is the ideal heart rate range to exercise in to achieve a specific training outcome — whether that's burning fat, improving cardiovascular endurance, raising your VO2 max, or recovering between sessions. It is expressed as a percentage of your maximum heart rate (HRmax).

The American Heart Association (AHA) recommends a target heart rate of 50–85% of maximum for aerobic exercise. Within that range, different intensities produce different physiological adaptations — which is why structuring training across multiple zones is far more effective than working at a single intensity.

Monitoring your heart rate during workouts ensures you are training at the right intensity for your goal — avoiding the common mistake of always training at the same moderate-hard pace, which produces diminishing returns over time.

How It Works — Formulas Explained

Formula / MethodEquationNotes
Tanaka Max HR208 − 0.7 × ageMore accurate for adults; validated in 351 studies (Tanaka et al. 2001)
Fox Max HR220 − ageClassic formula; tends to overestimate for younger, underestimate for older adults
% of Max HR methodTarget HR = HRmax × (intensity ÷ 100)Simple and widely used; slightly underestimates true exercise intensity
Karvonen (HRR) methodTarget HR = (HRmax − HRrest) × intensity + HRrestMore precise; accounts for individual fitness level via resting HR
Heart Rate Reserve (HRR)HRR = HRmax − HRrestThe "working range" of your heart; higher HRR = better cardiovascular fitness

Worked Examples

30-Year-Old — % of Max HR (Tanaka)

  • ·Age: 30, Max HR = 208 − 0.7 × 30 = 187 bpm
  • ·Zone 1 (50–60%): 94–112 bpm
  • ·Zone 2 (60–70%): 112–131 bpm
  • ·Zone 3 (70–80%): 131–150 bpm
  • ·Zone 4 (80–90%): 150–168 bpm
  • ·Zone 5 (90–100%): 168–187 bpm
  • ·Target at 65%: 187 × 0.65 = 122 bpm

45-Year-Old — Karvonen Method

  • ·Age: 45, Resting HR: 58 bpm
  • ·Max HR (Tanaka): 208 − 0.7 × 45 = 177 bpm
  • ·HRR = 177 − 58 = 119 bpm
  • ·Zone 2 (60–70% HRR): 119×0.60+58 to 119×0.70+58
  • ·= 129–141 bpm (vs. 106–124 bpm with % method)
  • ·Target at 70%: 119 × 0.70 + 58 = 141 bpm
  • ·Karvonen gives higher, more personalised zones

60-Year-Old — Fox vs Tanaka Comparison

  • ·Age: 60
  • ·Fox (220 − 60) = 160 bpm
  • ·Tanaka (208 − 0.7×60) = 166 bpm
  • ·Difference of 6 bpm grows with age
  • ·At 70%: Fox 112 bpm vs. Tanaka 116 bpm
  • ·For 60+ adults, Tanaka is significantly more accurate
  • ·Lab-measured max HR is always the gold standard

Karvonen vs. Percentage of Max HR — Which Should You Use?

% of Max HR

  • ✓ Simple — only needs your age
  • ✓ Universally understood and used in fitness literature
  • ✓ Great for beginners starting out
  • ✗ Does not account for individual fitness level
  • ✗ Can underestimate intensity for fit individuals

Karvonen (Heart Rate Reserve)

  • ✓ More precise — uses your actual resting HR
  • ✓ Accounts for fitness level (lower resting HR = wider zones)
  • ✓ Recommended for athletes and experienced exercisers
  • ✗ Requires accurately measured resting heart rate
  • ✗ Slightly more complex to calculate manually

The 5 Heart Rate Training Zones Explained

Zone 1 — Warm-Up / Recovery

50–60% HRmax

Very easy exercise. Used for warm-ups, cool-downs, and active recovery days. Fuelled almost entirely by fat. Excellent for beginners and post-workout sessions.

Zone 2 — Fat Burn / Aerobic

60–70% HRmax

Light to moderate effort — you can hold a conversation. The most important zone for building mitochondrial density and long-term fat oxidation. Aim for 80% of weekly volume here.

Zone 3 — Cardio / Aerobic

70–80% HRmax

Moderate-hard effort. Improves cardiovascular efficiency and VO2 max. Uses both fat and carbohydrate. Sometimes called the 'grey zone' — effective but less targeted than Z2 or Z4.

Zone 4 — Threshold / Hard

80–90% HRmax

Hard effort, only sustainable for 20–60 minutes. Raises lactate threshold and race pace. Primarily fuelled by carbohydrate. Essential for improving athletic performance and speed.

Zone 5 — Maximum / VO2 Max

90–100% HRmax

Maximum effort — sustainable for only 30 seconds to 3 minutes. The most powerful stimulus for raising VO2 max and anaerobic capacity. Use sparingly, only for advanced athletes.

Frequently Asked Questions

What is the most accurate way to find my max heart rate?

The gold standard is a maximal exercise test under medical supervision (e.g., a graded treadmill test). A reliable field alternative is a hard 3-mile run finishing with a 400m all-out sprint while measuring peak HR. Age-based formulas like Tanaka are accurate on average but can vary by ±10–15 bpm for individuals.

Why is the Karvonen method more accurate than % of max HR?

The Karvonen method uses your Heart Rate Reserve (HRmax − HRrest) rather than just max HR. Because resting heart rate reflects your current fitness level, it personalises the zones. A fit person with a resting HR of 45 bpm will have higher absolute training zones than an unfit person with the same max HR but a resting HR of 75 bpm.

What is a good resting heart rate?

For adults, a resting heart rate between 60–70 bpm is considered good; 50–60 bpm is excellent; below 50 bpm is typical of trained endurance athletes. Values above 80–90 bpm are associated with increased cardiovascular risk. Measure it first thing in the morning before sitting up.

What zone should I train in to burn fat?

Zone 2 (60–70% of max HR) is often called the 'fat burning zone' because fat contributes the highest percentage of fuel at this intensity. However, total calorie burn increases at higher intensities. For overall fat loss, a combination of Zone 2 training and periodic higher-intensity sessions is most effective.

How does heart rate change with age?

Maximum heart rate declines by approximately 1 bpm per year from age 20 onward. Resting heart rate does not change significantly with age alone, but does decrease with regular aerobic training. Using age-updated formulas and re-measuring your resting HR periodically ensures accurate zone calculations.

Can I use this calculator for cycling or swimming?

Yes — the underlying heart rate physiology is the same regardless of exercise mode. However, max HR in swimming is typically 10–15 bpm lower than running, and cycling 5–10 bpm lower, due to differences in muscle mass recruited and body position. If exercising in a specific mode, consider applying a sport-specific max HR if known.

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