Free Heart Rate Zone Calculator: Find Your Training Zones
Calculate your max heart rate and personalized training zones using the Tanaka, 220-age, Gulati, or Karvonen formulas.
Calculate Your Heart Rate Zones
What are heart rate zones?
Training zones translate exercise intensity into a specific BPM range you can target. Enter your age to see your max heart rate and personalized training zones.
- Zone 1 — Recovery50–60%
- Zone 2 — Aerobic60–70%
- Zone 3 — Endurance70–80%
- Zone 4 — Threshold80–90%
- Zone 5 — Maximum90–100%
Heart rate formulas estimate your training zones from age and (when used) resting heart rate. Individual maximum heart rate varies — a lab test is the most accurate method. Consult a healthcare provider before starting a new training program, especially if you have a cardiovascular condition.
Understanding Your Heart Rate Zones
Heart rate zones translate exercise intensity into a specific BPM range you can actually target during a workout. Instead of guessing how hard you're working, you can look at your watch and know whether you're building your aerobic base, working at threshold, or pushing toward VO2 max.
The zones are defined as percentages of your maximum heart rate (MHR). Each zone develops a different physiological system, which is why varying the intensity of your training matters as much as the volume.
The 5 Training Zones Explained
The 5-zone system is the standard used by most fitness watches, training apps, and coaches. Each zone has a distinct purpose:
- Zone 1 — Recovery (50–60% MHR): Active recovery, warm-ups, and cool-downs. You can speak in full sentences. Builds light aerobic capacity in beginners.
- Zone 2 — Aerobic / Easy (60–70% MHR): Builds aerobic base and improves fat metabolism. Conversational pace. This is where endurance athletes spend the majority of their training time.
- Zone 3 — Aerobic Endurance (70–80% MHR): Improves cardiovascular efficiency. You can speak in short sentences. Tempo and steady-state work happens here.
- Zone 4 — Lactate Threshold (80–90% MHR): Raises your sustainable race pace. Hard effort with only a few words possible at a time. Threshold intervals.
- Zone 5 — VO2 Max / Maximum (90–100% MHR): Improves maximum aerobic capacity. All-out effort, sustainable only for short intervals of 1–5 minutes.
5-Zone vs. 3-Zone Systems
The 3-zone system — used in polarized training — collapses the five zones into Easy, Moderate, and Hard, with boundaries at the body's two lactate thresholds (roughly 80% and 87% of MHR). It exists to make one specific argument about training distribution: that elite endurance athletes spend roughly 80% of their training in the easy zone, 20% in the hard zone, and almost none in the middle.
The 5-zone system is more useful for everyday training planning and works with virtually every fitness tracker. The 3-zone system is more useful if you're following a polarized training protocol or analyzing your training distribution. Use whichever matches how you actually plan your workouts.
How Accurate Are Heart Rate Formulas?
Every formula-based estimate of maximum heart rate has the same fundamental limitation: individual variation. Two healthy 40-year-olds can have actual max heart rates 20+ BPM apart. The formulas estimate the population average — they tell you what's likely, not what's true for you specifically.
The Four Methods Explained
Tanaka (2001) — Developed from a meta-analysis of 351 studies, this is the most accurate modern formula for the general population. It corrects the bias in the older 220-age formula, which significantly overestimates max HR for younger adults and underestimates it for older ones.
Tanaka formula — recommended default for most adults.
220 − Age (Fox & Haskell, 1971) — The classic. Created from a small sample and never intended as a clinical tool, but it stuck because of how easy it is to remember. Still widely taught and the most-searched MHR formula. Less accurate than Tanaka, especially at the extremes of age.
The classic formula. Easy to remember, less accurate.
Gulati (2010) — Developed specifically from data on 5,437 women undergoing stress tests at the Mayo Clinic. The standard 220-age formula consistently overestimates MHR for women; Gulati corrects this. Recommended if you're a woman looking for more accurate zone targets.
Gulati formula — validated for women.
Karvonen Method (1957) — Strictly speaking, Karvonen isn't a max heart rate formula at all — it's a method for calculating zone targets from your heart rate reserve (HRR), which is the difference between your maximum and resting heart rates. By incorporating resting HR, it produces more personalized zone ranges than the simple percentage-of-MHR approach. The trade-off is that you need to actually measure your resting HR.
Karvonen formula. Personalizes zones using your heart rate reserve.
When to Use a Lab Test Instead
If your training is structured enough that getting your zones right actually matters, the formulas can leave you 10–20 BPM off your true ranges. A graded exercise test (lab test or field test like a 20-minute time trial) gives you your actual maximum heart rate. Consider this if:
- You're following a structured training program for a specific event
- You've noticed your perceived effort doesn't match the BPM the formulas suggest
- You're an athlete whose age suggests a different MHR than the population norm
- You've taken a formula-based test and your real max HR is consistently higher or lower
- You're recovering from cardiac issues and need clinically accurate ranges
How to Use Heart Rate Zones for Training
Heart rate zones aren't just numbers — they're a tool for making sure your training delivers the adaptations you actually want. Most amateur athletes train too hard on easy days and too easy on hard days, which produces a lot of fatigue without much fitness gain. Zones fix that.
Zone 2 Training and Fat Burning
Zone 2 — 60–70% of maximum heart rate — has become one of the most discussed training concepts in recent years, popularized by physicians like Dr. Peter Attia and exercise scientists like Dr. Iñigo San Millán. The interest is well-founded: Zone 2 training builds mitochondrial density and improves fat oxidation more than any other intensity.
At Zone 2, your body burns a higher percentage of fat for fuel and develops the metabolic machinery that supports endurance, recovery, and long-term metabolic health. The trade-off is time — meaningful Zone 2 adaptations typically require 30–60 minute sessions, ideally 3+ times per week.
Most people accidentally drift above Zone 2 because it feels too easy. If you can hold a relaxed conversation, you're in the right place. If you're slightly breathless or speaking in short sentences, you've crept into Zone 3.
The 80/20 Rule for Endurance
Research on elite endurance athletes consistently finds that roughly 80% of their training is performed at low intensity (Zone 1–2), with the remaining 20% at high intensity (Zone 4–5). This distribution — called polarized training — produces better results than spending the majority of time at moderate intensity.
The counterintuitive part is the middle. Zone 3 feels productive — it's hard enough to feel like work, easy enough to sustain. But it's hard enough to accumulate fatigue and easy enough that it doesn't build top-end fitness. Polarized training treats Zone 3 as the trap to avoid: go easy on easy days, go hard on hard days, and skip the middle.
This is why the 3-zone system exists — it makes the distribution easy to track. If you log your training time in Easy, Moderate, and Hard buckets, you want roughly 80% easy, minimal moderate, and 20% hard.
Measuring Your Resting Heart Rate
For the Karvonen method to produce useful zones, your resting heart rate needs to be measured accurately. The best practice:
- Measure first thing in the morning, before getting out of bed
- Use a fitness tracker overnight, or count manually for 60 seconds
- Avoid measuring after caffeine, alcohol, illness, or hard training the day before
- Take an average over 5–7 days for a stable baseline number
- Resting HR generally falls between 40–80 BPM for healthy adults; trained endurance athletes often see 40–55 BPM
Tracking changes in your resting HR over time is itself useful — a sustained elevation often signals incomplete recovery, illness, or overtraining.
For a broader look at your overall fitness picture, also try our BMI calculator and body fat calculator.
Common Questions About Heart Rate Zones
What is the most accurate heart rate zone formula?
For the general adult population, the Tanaka formula (208 − 0.7 × age) is the most accurate. It corrects the systematic bias in the older 220-age formula. For women specifically, the Gulati formula (206 − 0.88 × age) tends to be even more accurate. The Karvonen method, which uses your resting heart rate, produces the most personalized zones — but only if your resting HR is measured accurately.
What heart rate zone is best for fat burning?
Zone 2 — roughly 60–70% of your maximum heart rate — is widely considered the best zone for fat metabolism. At this intensity, your body uses a higher percentage of fat as fuel and develops the metabolic infrastructure that supports long-term endurance and metabolic health. However, total calorie burn is higher in upper zones, so 'fat burning' depends on what you're optimizing for.
Is the 220-age formula accurate?
Not particularly. The 220-age formula was created in 1971 from a small sample and was never intended as a clinical reference. Research consistently shows it overestimates maximum heart rate for younger adults and underestimates it for older adults, sometimes by 15+ BPM. It's still useful as a rough estimate, but modern formulas like Tanaka are more accurate.
What's the difference between Karvonen and percentage-of-MHR methods?
The percentage-of-MHR method calculates zones as simple fractions of your max heart rate (e.g., Zone 2 = 60–70% of MHR). The Karvonen method calculates zones from your heart rate reserve — the difference between max HR and resting HR — then adds resting HR back. This produces higher BPM targets for the same intensity level, and the zones are more personalized because they account for your individual cardiovascular fitness.
How do I know if my max heart rate estimate is right?
Pay attention to perceived effort relative to the zone you're supposedly in. If a Zone 2 effort feels like a Zone 4 effort, your estimated MHR is probably too low. If a Zone 5 effort feels easier than it should, your estimated MHR may be too high. A field test — like a maximum effort during a hard interval session — will often reveal a heart rate higher than any formula predicts.
Should I train in Zone 2 every day?
For most amateur athletes, training in Zone 2 for the majority of weekly volume is a good default — but daily Zone 2 plus occasional high-intensity work is generally more effective than Zone 2 alone. The polarized training model suggests roughly 80% easy (Zone 1–2) and 20% hard (Zone 4–5), with minimal time in the middle zones. Recovery and progressive overload also matter — total rest days are still valuable.
Why is my heart rate higher than the formulas predict?
Individual maximum heart rate varies significantly from population averages. Genetics is the largest factor, but caffeine, temperature, hydration, sleep quality, and emotional state all affect heart rate response to exercise. If your HR is consistently 10+ BPM above what formulas predict, your true max HR is likely higher than estimated — recalculate your zones using your actual max if you've measured it during a hard effort.
Can I use heart rate zones for strength training?
Heart rate zones are designed for cardiovascular training, not strength work. During lifting, heart rate spikes and falls in patterns that don't match the steady-state intensities the zones describe. Rate of perceived exertion (RPE) and rep-based metrics (like reps-in-reserve) are more useful for strength training. Use heart rate zones for the conditioning portion of your program.
What's a normal resting heart rate?
For healthy adults, resting heart rate typically falls between 60–80 BPM. Athletes — particularly endurance athletes — often see 40–60 BPM due to a more efficient cardiovascular system. Resting HR below 40 BPM is normal in highly trained athletes but should be evaluated by a healthcare provider in non-athletes. Above 100 BPM at rest (tachycardia) warrants a medical conversation.
