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Heart Rate Calculator

Max heart rate and 5 Karvonen training zones

Results are estimates for informational purposes only — not professional financial, medical, or legal advice. See how we build and verify our calculators.

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Frequently Asked Questions

How is maximum heart rate calculated?

The standard formula is 220 − age. This is an estimate with ~10–12 bpm standard deviation. The most accurate method is a supervised graded exercise test. The Tanaka formula (208 − 0.7 × age) is also widely used for athletes.

What is the Karvonen formula?

Karvonen uses your Heart Rate Reserve (max HR − resting HR) to personalize zones. Zone target = resting HR + (HRR × zone %). A fit person with a low resting HR gets higher absolute zone values than someone less fit at the same age.

What zone is best for fat burning?

Zone 2 (60–70% of max HR) is the classic "fat burning zone" because fat is the primary fuel source. However, higher zones burn more total calories. For sustainable long-term fat loss, a mix of Zone 2 and Zone 4 workouts works best.

What is a good resting heart rate?

Normal resting HR for adults is 60–100 bpm. Athletes often have 40–60 bpm due to a stronger, more efficient heart. A lower resting HR generally indicates better cardiovascular fitness. Measure it in the morning before getting up.

How do I train in Zone 2?

Zone 2 training should feel like you can hold a conversation — breathless but not gasping. For most people this is a brisk walk, light jog, or easy cycling. Aim for 150+ minutes of Zone 2 per week for cardiovascular base building.

Training Zone Guide

Zone 1 (50–60%)

Warm-up / Recovery

Zone 2 (60–70%)

Fat burn / Aerobic base

Zone 3 (70–80%)

Aerobic fitness

Zone 4 (80–90%)

Anaerobic threshold

Zone 5 (90–100%)

Max effort / Sprint

Resting HR Reference

Elite athletes40–50 bpm
Excellent fitness50–60 bpm
Good / Average60–70 bpm
Above average risk70–90 bpm
Consult doctor90+ bpm

Why Heart Rate Zones Matter

Training in different heart rate zones produces different physiological adaptations. Working out without knowing your zones is like driving without a speedometer — you can get somewhere, but you might be going too fast or too slow to reach your goal efficiently.

Zone 2 training builds your aerobic engine and is the foundation of most elite endurance programs. Zone 4–5 work builds speed and power. A well-rounded program includes both.

The 80/20 Training Rule

Research on elite endurance athletes shows they spend approximately 80% of training time in low intensity (Zone 1–2) and 20% in high intensity (Zone 4–5). Most recreational athletes do the opposite — training in the "grey zone" (Zone 3) too much.

80% Easy (Zone 1–2)

Builds aerobic base, recovers well, sustainable volume

20% Hard (Zone 4–5)

Raises VO2 max, builds speed, interval training