Target Heart Rate Calculator
Find your target heart rate zone for exercise using the Karvonen formula, based on your age, resting heart rate, and desired intensity.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Your result
128 bpm
Target heart rate (low)
AI explanation
Formula
Max HR = 220 − age. THR = (Max HR − resting HR) × intensity% + resting HR (Karvonen formula)Worked example
Age 30, resting HR 60, 50-85% intensity
| Field | Value |
|---|---|
| Age | 30 |
| Resting heart rate | 60 |
| Intensity (low) | 50 |
| Intensity (high) | 85 |
| Estimated max heart rate | 190 |
| Target heart rate (low) | 125 |
| Target heart rate (high) | 171 |
Assumptions
- Uses the Karvonen (heart rate reserve) formula, which factors in resting heart rate rather than just a flat percentage of max HR, generally considered more personalized.
- Max heart rate is estimated with the standard 220 − age formula, itself an approximation with meaningful individual variation.
- Informational only — not personalized medical advice.
Frequently asked questions
What is a target heart rate zone?
The heart rate range you should aim for during exercise to work at a desired intensity — typically 50-70% of heart rate reserve for moderate exercise and 70-85% for vigorous exercise.
Why does the formula need my resting heart rate?
The Karvonen formula scales intensity off your heart rate reserve (max minus resting) rather than just max heart rate, which better accounts for individual fitness level — a fitter person with a lower resting HR gets a different target at the same %.
Is "220 minus age" an accurate max heart rate estimate?
It's a widely used population-average approximation, but individual max heart rate can vary by 10-20 bpm from this estimate — a supervised fitness test gives a more precise figure.
Related calculators
Sources
- The effects of training on heart rate; a longitudinal study — Annales Medicinae Experimentalis et Biologiae Fenniae. Effective 01-01-1957, reviewed 13-09-2026.
This calculator provides a general estimate only and does not constitute personalized medical advice. Consult a doctor before starting a new exercise program, especially if you have a heart condition.
Report a calculation issue