Heart Rate Calculator

Find your maximum heart rate and five training zones by age. Optionally add your resting heart rate to get Karvonen (heart rate reserve) zone targets.

Measure resting HR in the morning before getting up

Maximum Heart Rate

Training Zones

How to Use

  1. 1

    Enter your age in years.

  2. 2

    (Optional) Enter your resting heart rate - measured in the morning before rising - to unlock Karvonen training zones.

  3. 3

    Choose a formula: Tanaka is the more recent research-based formula; Fox (220 − age) is the classic standard.

  4. 4

    Click Calculate - your max heart rate and all 5 training zones appear instantly.

Formulas

Tanaka Formula (recommended)
Max HR = 208 − (0.7 × age)

Published by Tanaka et al. (2001) from a meta-analysis of 351 studies. Generally considered more accurate across age groups.

Fox Formula (classic)
Max HR = 220 − age

The widely cited original formula. Simple and still used broadly, though it tends to overestimate MHR in younger people and underestimate it in older adults.

Karvonen Method (with resting HR)
Target HR = ((MHR − RHR) × intensity%) + RHR

Uses Heart Rate Reserve (MHR − resting HR) to produce more personalised training zones. Requires knowing your resting heart rate.

What the Zones Mean

Zone 1 - Recovery (50-60%)

Very easy effort. Used for warm-up, cool-down, and active recovery between hard sessions.

Zone 2 - Aerobic Base (60-70%)

Comfortable conversational pace. Builds aerobic endurance and fat-burning efficiency. Core of most training plans.

Zone 3 - Aerobic (70-80%)

Moderate intensity. Breathing is heavier but sustainable. Improves cardiovascular fitness and lactate clearance.

Zone 4 - Threshold (80-90%)

Hard, near-maximum sustainable effort. Raises lactate threshold and race pace performance. Used in interval training.

Zone 5 - Maximum (90-100%)

All-out sprint effort. Only sustainable for short bursts. Develops peak speed and power. Not suitable for long durations.

Examples

Example 1 - Age 35 (Tanaka formula)

MHR = 208 − (0.7 × 35) = 184 bpm

Zone 2 (aerobic base): 110-129 bpm

Example 2 - Age 50 with resting HR of 60 (Karvonen)

MHR = 208 − (0.7 × 50) = 173 bpm

HRR = 173 − 60 = 113 bpm

Zone 2 Karvonen: (113 × 0.60 + 60) to (113 × 0.70 + 60) = 128-139 bpm

FAQ

The Tanaka formula is generally preferred as it is derived from a large meta-analysis and tends to be more accurate across age groups, particularly for older adults. Fox (220 − age) is still widely used and is the default in many devices and textbooks.
Measure first thing in the morning before getting out of bed. Place two fingers on your wrist or neck, count beats for 60 seconds. A typical resting HR is 60-100 bpm; well-trained athletes often see 40-60 bpm.
Age-based formulas give an estimate. Individual MHR can vary by ±10-20 bpm from the formula prediction due to genetics, fitness level, and health. A graded exercise test supervised by a professional provides the most accurate measurement.

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Training Tip

Most recreational runners spend too much time in Zone 3. Research consistently shows that spending 80% of training time in Zone 1-2 (easy) and 20% in Zone 4-5 (hard) produces better long-term results.

Zone Overview

Zone 1 - Recovery 50-60%
Zone 2 - Aerobic Base 60-70%
Zone 3 - Aerobic 70-80%
Zone 4 - Threshold 80-90%
Zone 5 - Maximum 90-100%

Disclaimer: This calculator is for informational purposes only and is not medical advice. Consult a healthcare professional before starting a new exercise programme, particularly if you have any cardiovascular conditions or health concerns.