Running pace calculator
Plan your running pace, finish time and even splits in kilometers or miles.
Zone 2 heart rate calculator
Find your estimated aerobic training range, with the method behind every number.
Your training inputs
Example valuesNo account needed. Calculations happen in your browser; your entries are not saved or sent to Century.
Example · Estimated Zone 2 range
108–126bpm
Age estimates are a starting point. These ranges do not measure your thresholds.
- Estimated maximum
- 180 bpm
- Other method
- 132–144 bpm
Zone 1
90–108
Zone 2
108–126
Zone 3
126–144
Zone 4
144–162
Zone 5
162–180
How it’s calculated
Estimated maximum heart rate = 208 − 0.7 × age (Tanaka). A measured maximum replaces this estimate when entered. In this five-zone model, Zone 2 is 60–70% of maximum heart rate. Heart rate reserve uses resting heart rate + 60–70% × (maximum − resting heart rate). These methods produce different ranges and do not locate your lactate or ventilatory thresholds.
Reference: Tanaka et al.: Age-predicted maximal heart rate
For general wellness information. This tool does not diagnose health conditions or replace medical advice.
Related tools
Understand your Zone 2 training range
Choose the method before choosing a target
Percent of maximum heart rate starts from zero; heart rate reserve starts from your resting heart rate. Using the same percentage with different starting points creates different BPM ranges. Choose the method used by your training plan before comparing its numbers with a wearable.
Enter your age for the Tanaka estimate, or use a measured maximum if you have one. Resting heart rate is needed for the reserve method. The selected method controls the main result and all five zones; the second estimate stays visible as a comparison.
An estimate is not a threshold test
Age-based maximum heart rate is a population estimate. Your own maximum may differ. Neither of these formulas measures the boundary between your physiological training zones.
The five-zone display uses ten-percentage-point bands from 50% to 100%. Adjacent ranges share a boundary. Use the named model consistently when comparing sessions, and follow your established exercise guidance.
Connect a training range with recovery context
A target range helps describe a planned session, but it does not account for the route, conditions or how you feel that day. Do not treat a formula as a requirement to reach a particular pulse.
Century brings available wearable workout and recovery signals together, so you can review training patterns beyond a single calculated range.
Frequently asked questions
How do I calculate my Zone 2 heart rate?
Choose a method. This tool uses 60–70% of maximum heart rate, or resting heart rate plus 60–70% of heart rate reserve. Enter a measured maximum if you know it; otherwise maximum heart rate is estimated from age.
Why do Zone 2 calculators give different numbers?
Zone definitions and formulas differ. Percent of maximum heart rate and heart rate reserve use different starting points. This tool names the method and shows both estimates so you can compare them without treating them as interchangeable.
What is Zone 2 for a 40-year-old?
The Tanaka age estimate gives a maximum of 180 bpm at age 40. With the percent-of-maximum method, Zone 2 is 108–126 bpm. With a resting heart rate of 60 bpm, the heart-rate-reserve method gives 132–144 bpm.
Can I use my Apple Watch or Garmin maximum heart rate?
You can enter a measured maximum from a credible exercise test or your established records. A single unusual wearable spike may be an error. Check the source before replacing the age estimate.
Does this measure my aerobic threshold?
No. These are formula-based training ranges, not a measurement of lactate or ventilatory thresholds. Different zone systems may label different intensities as Zone 2.
How are all five heart rate zones calculated?
This tool uses 50–60%, 60–70%, 70–80%, 80–90% and 90–100% for Zones 1–5. The percentages apply either to maximum heart rate or to heart rate reserve plus resting heart rate, depending on the selected method.