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Heart Rate Zone Calculator

Fitness & Health

Calculate your 5 personalised heart rate training zones using the Karvonen or basic method. Optimise every workout — fat burning, aerobic, anaerobic and peak performance.

Providing this activates the more accurate Karvonen formula.

What Is a Heart Rate Zone Calculator?

A heart rate zone calculator divides your working heart rate into five intensity bands — from very light recovery work right up to all-out maximum effort sprints. Training in the right zone ensures every session serves a specific physiological purpose, whether that is burning fat, building aerobic capacity or improving anaerobic power.

This tool supports two calculation methods: the simple maximum heart rate (% HRmax) method and the more personalised Karvonen formula that uses your Heart Rate Reserve (HRR).

How It Works — The Formulas

1. Maximum Heart Rate

HRmax = 220 − Age

The most widely used estimate. A 30-year-old has an estimated HRmax of 190 bpm. The actual value can vary ±10–12 bpm between individuals.

2. Karvonen Formula

THR = (HRmax − HRrest) × intensity + HRrest

Uses your Heart Rate Reserve (HRR = HRmax − resting HR). Because it accounts for your fitness baseline, it produces zones that are individually adjusted.

The 5 Heart Rate Training Zones Explained

ZoneNameIntensityPrimary BenefitUse Case
Z1Very Light50–60%Recovery, general healthWarm-up, cool-down, active recovery days
Z2Fat Burning60–70%Fat oxidation, aerobic baseLong slow runs, easy cycling, daily movement
Z3Aerobic70–80%Cardiovascular efficiencySteady-state cardio, tempo runs, triathlon training
Z4Anaerobic80–90%Lactate threshold, speedInterval training, race-pace work, HIIT
Z5Maximum90–100%Peak power, sprint capacityShort all-out sprints, max effort intervals

How to Measure Your Resting Heart Rate

Your resting heart rate (RHR) is best measured first thing in the morning before getting out of bed. Count your pulse for a full 60 seconds, or for 30 seconds and multiply by 2. Normal adults range from 60–100 bpm. Athletes often have an RHR of 40–60 bpm. Most modern smartwatches measure RHR automatically overnight.

Benefits of Heart Rate Zone Training

  • ✓Prevent overtraining — Most athletes train too hard on easy days and not hard enough on hard days. Zones enforce the right effort.
  • ✓Maximise fat burning — Zone 2 training trains your body to use fat as the primary fuel source, improving body composition without exhaustion.
  • ✓Improve race performance — Zone 4–5 intervals raise your lactate threshold, directly improving your pace at race effort.
  • ✓Track fitness progress — As you get fitter, your heart rate at the same speed drops — your zones reflect improved cardiovascular efficiency.
  • ✓Recovery management — Staying in Zone 1–2 on easy days promotes blood flow and repairs muscular micro-damage without additional training stress.

Example Calculation

Profile: Age 35, Resting HR 62 bpm

HRmax = 220 − 35 = 185 bpm

HRR = 185 − 62 = 123 bpm

Zone 1 (50–60%): (123 × 0.50) + 62 = 123–136 bpm

Zone 2 (60–70%): (123 × 0.60) + 62 = 136–148 bpm

Zone 3 (70–80%): (123 × 0.70) + 62 = 148–160 bpm

Zone 4 (80–90%): (123 × 0.80) + 62 = 160–173 bpm

Zone 5 (90–100%): (123 × 0.90) + 62 = 173–185 bpm

Frequently Asked Questions

Which method should I use — basic or Karvonen?

Use the Karvonen method whenever possible. Because it uses your resting heart rate, it produces zones that are personalised to your current fitness level. The basic (% HRmax) method is fine as a starting point but can over-estimate zones for very fit individuals.

Is the 220 − age formula accurate?

It is a popular estimate with a standard deviation of around ±10–12 bpm, so your actual HRmax could be 10 beats higher or lower. For critical training it is best to perform a field test (e.g. a graded exercise test) to measure your true maximum.

What heart rate zone is best for weight loss?

Zone 2 (60–70%) maximises the proportion of calories burned from fat and is sustainable for long sessions. However, higher-intensity training burns more total calories per minute, so a mix of Zone 2 steady sessions and Zone 4 intervals is optimal for body composition.

Can I use a fitness tracker instead of this calculator?

Most wearables estimate zones using your age-based HRmax with no resting HR adjustment. This tool with your resting HR entered will generally give more accurate personalised zones than factory defaults.

What is VO₂ max and how is it estimated?

VO₂ max is the maximum volume of oxygen your body can use per minute per kilogram of body weight (ml/kg/min). This tool estimates it using the Uth–Sørensen formula: 15 × (HRmax ÷ HRrest), which correlates well with lab measurements and only requires your resting heart rate.

How long should I train in each zone?

A common evidence-based split is the 80/20 rule: roughly 80% of weekly training volume in Zone 1–2 and 20% in Zone 3–5. This develops the aerobic base while allowing sufficient high-intensity stimulus and meaningful recovery.

Explore This Tool in Context

Heart Rate Zone 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.

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