Heart Rate Zone Calculator

This calculator uses common formulas to estimate heart-rate zones. The formulas and zone boundaries are different ways of organizing training intensity; they do not measure your response to exercise.

1. Maximum Heart Rate (Max HR) Formulas

If you don't input a verified maximum heart rate from a laboratory stress test, the tool calculates an estimate using one of three options:

• Fox Formula: The most common traditional standard. $$\text{Max HR} = 220 - \text{Age}$$
• Tanaka Formula: A modernized alternative developed through multi-subject analysis to account for shifts across older populations. $$\text{Max HR} = 208 - (0.7 \times \text{Age})$$
• Gulati Formula: A formula specifically researched and validated for female cardiovascular traits to reduce overestimation. $$\text{Max HR} = 206 - (0.88 \times \text{Age})$$

2. Pacing Methodology Calculations

Max HR Percentage Method

Calculations are straight percentages mapped across your absolute Maximum Heart Rate: $$\text{Zone Min/Max BPM} = \text{Max HR} \times \text{Zone Percentage}$$

Karvonen Formula (Heart Rate Reserve)

This method utilizes your Heart Rate Reserve (HRR), which represents the usable range between resting and maximum capacity: $$\text{HRR} = \text{Max HR} - \text{Resting HR}$$ Once the reserve is established, individual target steps are calculated using intensity weights: $$\text{Target BPM} = \text{Resting HR} + (\text{Zone Percentage} \times \text{HRR})$$

Joe Friel Lactate Threshold Method

Indexed against your specified Lactate Threshold Heart Rate (LTHR). This formula assigns tailored athletic coefficients: $$\text{Target BPM} = \text{LTHR} \times \text{Friel Zone Percentage}$$

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A General Guide to Training Zones

Zone boundaries and labels vary by method and sport. These calculated ranges are estimates, not medical limits or a guarantee of a particular training effect.