Heart Rate Zone Calculator

Calculate your five training heart rate zones based on age and resting heart rate.

Age

years

Resting Heart Rate

BPM

Measure first thing in the morning for best accuracy

Calculation Method

Max Heart Rate

—

Estimated maximum

Heart Rate Reserve

—

Max minus resting

Training Zones

Zone 1 Recovery

50-60%

—

Warm-up, cool-down, active recovery

Zone 2 Fat Burn

60-70%

—

Base endurance, easy conversation pace

Zone 3 Aerobic

70-80%

—

Moderate effort, improves cardiovascular fitness

Zone 4 Anaerobic

80-90%

—

Hard effort, increases speed and power

Zone 5 VO2 Max

90-100%

—

Maximum effort, short bursts only

Heart Rate Training Guide

What Each Zone Does

Zone 1 (Recovery): Very light effort. Used for warm-ups, cool-downs, and recovery between hard workouts. Builds the foundation of aerobic fitness without fatigue.
Zone 2 (Fat Burn): Comfortable effort where you can hold a full conversation. Builds aerobic base, improves fat metabolism, and is sustainable for long durations. This is where most endurance training should occur.
Zone 3 (Aerobic): Moderate effort, slightly harder to hold a conversation. Improves overall cardiovascular efficiency and is the transition zone between easy and hard training.
Zone 4 (Anaerobic): Hard effort, can only speak in short phrases. Builds lactate threshold, increases speed and power. Typically sustained for 10-30 minutes in intervals.
Zone 5 (VO2 Max): All-out effort, cannot speak. Builds maximum cardiovascular capacity. Only sustainable for 30 seconds to 3 minutes. Used sparingly in training.

Measuring Resting Heart Rate

For the most accurate resting heart rate:

Measure first thing in the morning before getting out of bed
Use a chest strap or pulse oximeter for accuracy
Take readings for 3-5 days and use the average
Avoid caffeine and alcohol the evening before

Training by Goal

Weight loss: Focus on Zones 2-3 with occasional Zone 4 intervals
Endurance: Spend 80% of time in Zones 1-2, 20% in Zones 3-4
Performance: Structured mix of all zones with emphasis on Zone 4-5 intervals and Zone 1-2 recovery
General health: 150 minutes per week in Zones 2-3

Standard vs. Karvonen Method

The Standard method calculates zones as simple percentages of max heart rate (220 - age). It is simpler but less personalized.

The Karvonen method uses your heart rate reserve (max HR minus resting HR) and adds back your resting HR. This produces more accurate zones because it accounts for your individual fitness level. A lower resting heart rate generally indicates better cardiovascular fitness.

Disclaimer: This calculator provides estimates for informational purposes only. Consult your healthcare provider before starting a new exercise program, especially if you have a heart condition or other health concerns.

Heart-Rate Zones, Actually Measured

The classic Haskell-Fox formula (220 − age) for max heart rate has an average error of ±12 bpm, per a 2001 UCLA meta-analysis. The Tanaka formula (208 − 0.7 × age) is tighter (±7 bpm) and preferred in sports medicine. The AHA's 5-zone model uses 50-60%, 60-70%, 70-80%, 80-90%, and 90-100% of HRmax — translating for a 40-year-old to 90-108, 108-126, 126-144, 144-162, and 162-180 bpm under Tanaka.

Zone distribution of elite endurance athletes is revealing: 2020 International Journal of Sports Physiology analysis of 87 world-class runners found 75-80% of weekly training time in Zone 1-2 (easy), 5-10% in Zone 3 (threshold), and 15-20% in Zone 4-5 (VO2 max and above). Recreational runners typically invert this ratio and spend 50-60% in Zone 3 — the 'gray zone' — which limits adaptation.

Actual resting and max heart rates vary more than formulas suggest. Fitbit's 2022 analysis of 30+ million users found average resting HR of 63 bpm for women and 62 for men, with trained athletes often in the 40-50 range and sedentary adults 70-80. Individual HRmax can be 15+ bpm above or below age-based predictions, which is why VO2 max lab testing or a supervised max-effort field test remains the gold standard for serious training plans.

Sources: UCLA 2001 HRmax meta-analysis, Tanaka 2001, IJSPP 2020, Fitbit Health Data Report

Frequently Asked Questions

What zone burns the most fat?

Zone 2 (60-70% max HR) burns the highest percentage of calories from fat, which is why it is called the "fat burn" zone. However, higher intensity zones burn more total calories per minute, which can lead to greater overall fat loss. For weight loss, a mix of Zone 2 endurance work and higher-intensity intervals is most effective. Consistency matters more than staying in a specific zone.

How do I find my max heart rate?

The simplest estimate is 220 minus your age, though this can be off by 10-15 beats per minute for individuals. A more accurate method is a supervised maximal exercise test with a cardiologist. Field tests, like running an all-out mile after warming up and checking your peak heart rate, provide a better personal estimate but carry risk for untrained individuals.

Is the 220-minus-age formula accurate?

The 220-minus-age formula is a rough average that works reasonably well at the population level but can be inaccurate by 10-15 BPM for individuals. Some people naturally have higher or lower max heart rates regardless of fitness level. If your training feels too easy or too hard based on the calculated zones, consider adjusting or getting a supervised max HR test.

How long should I train in each zone?

Training distribution depends on your goals. A general guideline is the 80/20 rule: spend 80% of training time in Zones 1-2 (easy aerobic) and 20% in Zones 3-5 (moderate to hard). For beginners, spend more time in Zone 2 building a base. For performance, include 1-2 high-intensity sessions per week in Zones 4-5, with adequate recovery between them.