Heart Rate Zone Calculator
Not all miles are created equal. Train smarter by identifying your 5 heart rate zones. Whether you are building endurance or raw speed, precision starts here.
Estimated Max Heart Rate
Zone Training: The Athlete's Secret
Many beginners make the mistake of training in the "Grey Zone"—too hard to be easy, but too easy to be hard. This leads to burnout without progress. Professional athletes train differently: they spend 80% of their time going slow (Zone 2) and 20% going incredibly fast (Zone 5).
Our Heart Rate Zone Calculator gives you the exact BPM numbers you need to structure your training like a pro.
Decoding the 5 Zones
Each zone triggers different physiological adaptations in your body.
Zone 1: Very Light (50-60%)
Purpose: Warm up / Recovery.
You can hold a conversation easily. Blood flow increases to muscles to aid recovery.
Zone 2: Light (60-70%)
Purpose: Endurance & Fat Loss.
This is the sweet spot. It builds aerobic base and teaches your body to burn fat efficiently.
Zone 3: Moderate (70-80%)
Purpose: Aerobic Capacity.
Often called "Tempo." Breathing is heavier. Improves blood circulation and efficiency.
Zone 4: Hard (80-90%)
Purpose: Threshold.
You can only utter a few words. Increases lactic acid tolerance and high-speed endurance.
Zone 5: Maximum (90-100%)
Purpose: Peak Performance.
All-out sprint pace. Can only be sustained for seconds or very few minutes. Improves power and neuromuscular speed.
Finding Your Max Heart Rate
The zones are percentages of your maximum. We calculate this automatically using the Haskell & Fox formula:
Example: If you are 40 years old, your estimated Max HR is 180 bpm. Zone 2 would be 108-126 bpm.
Marathon Training
Long runs should be strictly in Zone 2. If you drift into Zone 3, you are burning glycogen too fast and won't build endurance.
HIIT Workouts
High Intensity Interval Training relies on spiking your HR into Zone 4 or 5 for short bursts, followed by Zone 1 recovery.
Beginners
New runners often try to go too fast. Sticking to Zone 2 ("conversational pace") prevents injury and makes running enjoyable.
Frequently Asked Questions
What happens if I exceed Zone 5?
Zone 5 caps at 100% of your max. If you see a number higher than your calculated Max HR, it simply means your *true* Max HR is higher than the age-based formula predicted. You should update the "Max HR" input manually.
Does Resting Heart Rate matter?
Yes. The "Karvonen Method" (not used in this basic calculator) uses your Resting HR to determine "Heart Rate Reserve." It's slightly more accurate for very fit people with low resting rates.
Why is my heart rate so high when jogging?
This is called "Cardiac Drift." As a beginner, your heart works hard even at slow speeds. With consistent Zone 2 training, your heart will become more efficient, and your HR will drop for the same pace.
Medical Disclaimer
Consult a doctor before starting intense exercise (Zone 4/5), especially if you have a history of heart conditions. Listen to your body.
Data Privacy
We do not store your health data. This tool runs entirely in your browser.