Heart Rate Zone Calculator
Find your 5 heart rate zones for smarter training
MHR Formula
Your Estimated Max HR
This is a statistical estimate. Individual variation of ±10–12 bpm is normal. The most accurate way is to check your max HR during a race.
Heart Rate Zone Distribution
| Zone | Heart Rate (bpm) | Intensity |
|---|
Zone 2: Endurance
This is where the magic happens. At an easy conversational pace, your capillaries and mitochondria develop. This is why elite runners spend 80% of their training here.
Zone 1 · Recovery
Between walking and easy jogging. Almost too easy to call it running.
What happens in your body
Increased blood circulation repairs micro-damage from previous training. Most energy comes from fat.
How to use this zone
Use for warm-up, cool-down, or recovery runs after hard training days.
Talk Test
You can sing. Not even slightly breathless.
Zone 2 · Endurance
Easy conversational pace. If it feels slow, you're doing it right.
What happens in your body
Capillaries multiply, mitochondria grow and increase. Fat-burning capacity improves. These adaptations don't happen as well in Zone 3–4.
How to use this zone
Spend most of your weekly running here. The most common mistake is running Zone 2 too fast.
Talk Test
You should be able to speak in complete sentences comfortably.
Zone 3 · Tempo
'Moderately hard' intensity. Conversation starts breaking up.
What happens in your body
Aerobic capacity improves, but Zone 2 benefits decrease. Many runners unconsciously drift into this zone (no man's land).
How to use this zone
Rarely targeted intentionally. Naturally drifts up in the second half of long runs.
Talk Test
Short sentences are fine, but long conversation is difficult.
Zone 4 · Threshold
'Hard' intensity. Sustainable for 20–30 minutes at most.
What happens in your body
You reach lactate threshold. Training here helps your body process lactate faster.
How to use this zone
Once a week tempo run: 10 min warm-up → 20–30 min in Zone 4 → cool-down.
Talk Test
A word or two at most. Full sentences are impossible.
Zone 5 · VO2Max
Near all-out effort. Sustainable for 1–5 minutes.
What happens in your body
You reach or approach VO2Max. Most energy comes from anaerobic pathways.
How to use this zone
Reached during 800m–1200m interval training. More than once a week increases injury risk.
Talk Test
Speaking is impossible. All focus is on breathing.
Why is Zone 2 confusing?
"My Garmin says Zone 3, but this says Zone 2. Which is right?" Both can be correct. The name 'Zone 2' is the same, but each device and method defines it differently. If it's confusing, do this: 1. Whatever system you use, if you can 'hold a comfortable conversation,' it's Zone 2. 2. If your Garmin/Polar doesn't match how you feel, check the max HR setting on your device. 3. The most reliable method is the Talk Test — trust your body's signals over numbers.
Frequently Asked Questions
1. "Is the '220 minus age' formula accurate?"
Individual variation can be ±10–12 bpm. This calculator defaults to the Tanaka formula (208 − 0.7 × age), validated with 18,000+ subjects, which is slightly more accurate. The best approach is to check your actual max HR during a race.
2. "Should I use %MaxHR or Karvonen?"
If you know your resting heart rate, we recommend Karvonen. The lower your resting HR (= better fitness), the bigger the difference between the two methods, and Karvonen better reflects your actual intensity.
3. "How do I measure my resting heart rate?"
Wake up naturally without an alarm, lie still for 1–2 minutes, and measure. A 3-day average is ideal. If you have a smartwatch, your sleep-time lowest HR is also a good reference.
4. "How do I set these values on my Garmin/Polar watch?"
Most running watches let you customize heart rate zones in settings. Simply enter this calculator's results directly into your device.
How does this calculator work?
Step 1: Max Heart Rate Estimation Estimates the theoretical maximum heart rate your heart can reach based on age. The default Tanaka formula (208 − 0.7 × age) comes from a 2001 meta-analysis of 18,712 subjects. Step 2: Heart Rate Zone Calculation · %MaxHR method: Simple percentage split of max heart rate. Quick and easy, but applies the same ratio to everyone. · Karvonen method: Splits based on Heart Rate Reserve (HRR = Max − Resting). Reflects fitness level, which is why exercise physiologists prefer it.
How to Measure Resting Heart Rate
Lie down or sit quietly for 1 minute after waking up and count your pulse. If you have a smartwatch, your average sleep heart rate is a good reference. Typically 50–80 bpm is normal; dedicated runners often see 40–60 bpm.
This calculator provides estimates based on general formulas. Consult a doctor if you have heart conditions or are starting a new exercise program.
This calculator shows the 'range' of your HR zones, but the AI coach designs 'how to use them' — weekly schedules, intensity distribution, and race strategy.
Get Your Training Plan — $2.99