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What is Heart Rate Zone Calculator?

Free heart rate zone calculator. Enter your age (and optionally resting heart rate) to get your 5 training zones via Karvonen, Tanaka, and 220-age methods — all side-by-side. No signup.

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HR Zone Calculator runs entirely in your browser using JavaScript (browser). Your data never leaves your device.

Free Heart Rate Zone Calculator

Find your heart rate training zones for cardio programming. Enter your age and optionally your resting heart rate (for the Karvonen reserve method). See all 5 zones (recovery, aerobic base, aerobic, threshold, VO2 max) via three methods side-by-side: 220-age, Tanaka (more accurate for age 40+), and Karvonen heart rate reserve (most personalized when you know your resting HR).

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220 − age

185

max HR (bpm)

Tanaka

184

max HR (bpm)

Zone
220 − age
Tanaka

Z1 Recovery

Active recovery, warm-up

93–111

bpm

92–110

bpm

Z2 Aerobic Base

Fat burn, mitochondrial dev

111–130

bpm

110–129

bpm

Z3 Aerobic

Cardiovascular conditioning

130–148

bpm

129–147

bpm

Z4 Threshold

Lactate threshold, race pace

148–167

bpm

147–166

bpm

Z5 VO₂ Max

Maximal effort, speed

167–185

bpm

166–184

bpm

❤️ Train smarter with your zones

Cardio workout plans →Today's WOD →Fitness Age →More calculators →

All calculations run in your browser. No data is sent to any server.

Frequently Asked Questions

Heart rate zones divide your cardiovascular effort into 5 intensity bands, each targeting different physiological adaptations. Zone 1 (50–60% max HR): active recovery, improves blood flow. Zone 2 (60–70%): aerobic base, fat oxidation, mitochondrial development. Zone 3 (70–80%): aerobic conditioning, improves cardiovascular efficiency. Zone 4 (80–90%): lactate threshold, improves sustained high-intensity capacity. Zone 5 (90–100%): VO2 max, maximal aerobic capacity.
The classic 220-age formula is simple but has high individual variability (±10–12 bpm). The Tanaka formula (208 − 0.7 × age) was developed from a larger, more diverse dataset and performs better for older adults. The Karvonen heart rate reserve method is the most personalized — it accounts for your resting HR, reflecting your individual cardiovascular fitness. If you know your resting HR (measure it lying still after waking), use Karvonen.
Zone 2 training (60–70% max HR, or the level where you can hold a conversation) has gained popularity because it efficiently builds aerobic base, improves fat oxidation, and develops mitochondrial density without significant recovery cost. Dr. Peter Attia and others have popularized high zone 2 volume (3–4 hours/week) as a foundation for long-term cardiovascular health. Most people training by feel train too hard in zone 3 (the "grey zone") — a heart rate monitor helps you stay in zone 2.
Measure your resting heart rate first thing in the morning before getting out of bed. Lie still for 1–2 minutes, then count your heartbeats for 60 seconds (or 30 seconds × 2). A healthy adult resting HR is typically 60–100 bpm; endurance athletes often have resting HRs of 40–60 bpm. A lower resting HR generally indicates better cardiovascular fitness.
The Karvonen formula calculates target HR using heart rate reserve (HRR): Target HR = resting HR + (heart rate reserve × intensity %). Heart rate reserve = max HR − resting HR. For example, for zone 2 (60–70%) with max HR of 180 and resting HR of 60: HRR = 120. Zone 2 lower = 60 + (120 × 0.60) = 132. Zone 2 upper = 60 + (120 × 0.70) = 144 bpm.

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Heart Rate Zones Explained

Training in the correct heart rate zone determines the physiological adaptation you get from a session. Spending the right amount of time in each zone — rather than always training at the same moderate intensity — is the core of polarized training, which research shows outperforms moderate-intensity training for improving VO2 max and endurance performance.

Zone 2: The Foundation

Zone 2 (60–70% max HR) develops aerobic base and mitochondrial density with minimal recovery cost. At this intensity you should be able to hold a conversation — if you cannot, you are in Zone 3. Endurance coaches typically recommend 3–5 hours of Zone 2 per week as the foundation of an aerobic training block. Most athletes who train by feel chronically under-train Zone 2 and over-train Zone 3 — a heart rate monitor fixes this.

Zone 4–5: Quality Work

Zones 4 and 5 target lactate threshold and VO2 max respectively — the adaptations that determine race performance and peak fitness. These sessions are short, intense, and require significant recovery. Classic protocols: 4×4 min intervals at Zone 4–5 (Norwegian VO2 max protocol), 20-min threshold runs, or Tabata-style HIIT. Limit high-intensity work to 2–3 sessions per week to avoid overtraining.

Apply Your Zones With Structured Training

Knowing your zones is step one — applying them in structured workouts is step two. For cardio programs built around heart rate zones, try RowGress workouts, grab today's WOD, or check your Fitness Age to benchmark your cardiovascular fitness. Explore all free fitness calculators on RowGress.