Heart Rate Zone Calculator
Calculate your 5 heart rate training zones from age and resting pulse. Percent-of-max-HR and Karvonen heart rate reserve methods with bpm ranges.
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What is Heart Rate Zone Calculator?
The Heart Rate Zone Calculator estimates your five cardio training zones from your age, resting pulse, and optional measured max HR. It supports both the simple percent-of-max-HR method and the Karvonen heart rate reserve formula, giving you bpm targets for recovery rides through maximum intervals.
Key Benefits
- Train at the right intensity instead of guessing by feel
- Personalized zones via resting HR with the Karvonen method
- Balances easy and hard work to prevent overtraining
- No sign-up, no upload, works offline in the browser
Common Use Cases
- •Building an aerobic base with Zone 2 runs and rides
- •Structuring interval sessions with accurate upper-zone targets
- •Checking whether your easy days are truly easy
- •Setting bpm alerts on a watch or bike computer
How to Calculate Your Heart Rate Training Zones
- Enter your age: Type your age in the first field — this estimates your max heart rate at 220 minus age.
- Add your resting heart rate (optional): Enter your resting HR, measured right after waking, to unlock the more accurate Karvonen heart-rate-reserve method.
- Override max HR if you know it (optional): If a lab test or field effort gave you a measured max, enter it to replace the estimate before calculating.
- Calculate and read the zones: Press Calculate to see all five zones in bpm, from Zone 1 recovery up to Zone 5 maximal effort, and press Reset to start over.
Key Features
- Two calculation methods: percent of max HR and Karvonen heart rate reserve
- Five color-coded training zones with exact bpm ranges
- Optional custom max heart rate override
- Resting HR input unlocks the more accurate Karvonen method
- Works 100% offline in your browser with no data upload
- Accessible design with screen reader announcements
Frequently Asked Questions
How is my max heart rate estimated?
With the classic 220 − age formula, rounded to the nearest beat. If you know your real max from a lab test or a hard race effort, enter it in the max HR field to override the estimate.
What changes when I enter a resting heart rate?
The calculator switches from simple percentages of max HR to the Karvonen heart-rate-reserve method, which computes (max − resting) × intensity + resting and is widely considered more accurate for training targets.
What are the five zones used for?
Zone 1 (50–60% of max) is warm-up and recovery, Zone 2 builds aerobic base, Zone 3 is tempo work, Zone 4 is threshold, and Zone 5 (90–100%) is maximal effort such as VO2 max intervals.
Do my numbers get saved or shared anywhere?
No. Age and heart-rate values are processed in your browser only — nothing is uploaded or stored, and the health note reminds you this is guidance, not medical advice.