Heart Rate Zone Calculator (5 Zones, %HRmax) · Free

Zone	Range	What it trains
Z1	Recovery 93–111 bpm	Active recovery and warm-up; promotes blood flow without adding fatigue. Very easy, RPE 1–2. Full conversation, barely breathing hard.
Z2	Endurance 111–130 bpm	Aerobic base, fat oxidation and capillary density, the bread-and-butter zone. Comfortable, RPE 3–4. Can hold full sentences.
Z3	Tempo 130–148 bpm	Aerobic capacity and muscular endurance; 'moderately hard' steady work. Working, RPE 5–6. Short sentences only.
Z4	Threshold 148–167 bpm	Lactate threshold, your sustainable race-pace ceiling. Hard, RPE 7–8. A few words at a time.
Z5	VO₂max 167–185 bpm	Maximal aerobic power and VO₂max via short, hard intervals. Very hard to maximal, RPE 9–10. No talking.

Recovery

93–111 bpm

Endurance

111–130 bpm

Tempo

130–148 bpm

Threshold

148–167 bpm

VO₂max

167–185 bpm

The five-zone model explained

The %HRmax model needs one number, your maximum heart rate, so most watches default to it. Zone 1 (50–60%) is recovery. Zone 2 (60–70%) builds the aerobic base and fat oxidation. Zone 3 (70–80%) is tempo. Zone 4 (80–90%) is lactate threshold. Zone 5 (90–100%) develops VO₂max.

How to use these zones

Easy days in Zones 1–2, hard days in Zones 4–5, nothing in the gray zone between. A proven split is about 80% easy, 20% hard. Heart rate lags effort by 1–3 minutes and drifts in heat, so judge short intervals by pace, power or feel.

When %HRmax falls short

%HRmax ignores resting heart rate, so a fit athlete and a beginner of the same age get identical zones. Karvonen adds resting HR. LTHR zones anchor to a tested threshold. Both are more individual.

Worked example

For an athlete with a maximum heart rate of 185 bpm:

Zone 1, Recovery (50–60%)	93–111 bpm
Zone 2, Endurance (60–70%)	111–130 bpm
Zone 3, Tempo (70–80%)	130–148 bpm
Zone 4, Threshold (80–90%)	148–167 bpm
Zone 5, VO₂max (90–100%)	167–185 bpm

Frequently asked questions

What heart rate zone burns the most fat?

Fat is the dominant fuel in Zones 1–2, about 50–70% of maximum heart rate. Higher zones burn more total calories but more from carbohydrate. Steady Zone 2 builds the fat-burning base.

How long should I spend in Zone 2?

Most endurance athletes should spend 70–80% of weekly training time in easy Zone 2. It builds aerobic capacity with low fatigue, leaving room for a small dose of hard Zone 4–5 work.

Why is my heart rate higher than my zones suggest?

Heart rate rises with heat, dehydration, caffeine, stress, illness and fatigue, and drifts upward on long efforts. If it runs consistently high, your maximum heart rate estimate is too low. Test it.

Are heart-rate zones the same for cycling and running?

No. Running produces a maximum heart rate 5–10 bpm higher than cycling for the same person, because more muscle is active. Set zones per sport, ideally from a sport-specific threshold test.

Sources

Tanaka, Monahan & Seals (2001). “Age-predicted maximal heart rate revisited.” J Am Coll Cardiol 37(1):153–156.
American College of Sports Medicine. ACSM's Guidelines for Exercise Testing and Prescription, %HRmax intensity classifications.