How it works
target HR = resting + intensity% × (max − resting)
This page keeps the calculation centered on one relationship: target HR = resting + intensity% × (max − resting). Inputs are normalized before the final display, which keeps mile, kilometer, pace, speed, or zone outputs from drifting because of rounding. Use the number as a consistent model output, then layer in terrain, weather, recovery, and race execution. Next steps: related calculator 1, related calculator 2. Keep the fixed reference values in view: 220, 208, 0.7, 50–60%, 60–70%, 70–80%, 80–90%, 90–100%.
Sources
- Karvonen heart-rate reserve method Karvonen, M. J., Kentala, E., & Mustala, O. (1957). “The effects of training on heart rate.” Annales Medicinae Experimentalis et Biologiae Fenniae 35(3), 307–315.
- Maximum heart rate estimates Fox et al. (220 − age); Tanaka, Monahan & Seals (2001), “Age-predicted maximal heart rate revisited,” J. Am. Coll. Cardiol. 37(1), 153–156 (208 − 0.7 × age).
- Heart-rate reserve method (origin) Karvonen, M. J., Kentala, E., & Mustala, O. (1957). “The effects of training on heart rate: a longitudinal study.” Annales Medicinae Experimentalis et Biologiae Fenniae 35(3), 307–315 — the original heart-rate reserve (HRR) method.
- ACSM exercise-intensity guidelines American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing and Prescription, 11th ed. (2021), Wolters Kluwer — endorses %HRR (Karvonen) for prescribing aerobic exercise intensity.
FAQ
When should I use the heart rate zone calculator?
Use it when you want a fast planning number before a run, race, workout, or gear decision. It gives you a consistent estimate without asking you to create an account. Keep the fixed reference values in view: 1, 50–60%, 2, 60–70%, 3, 70–80%, 4, 80–90%.
What inputs matter most?
The best result comes from honest, current inputs. Recent race times, realistic body measurements, accurate workout data, and the correct unit setting matter more than perfect formatting. Keep the fixed reference values in view: 2, 60–70%, 190, 60, 138–151.
How should I read the result?
Treat the output as a planning reference, not a promise. Use it to compare options, set a target range, or sanity-check your watch data before making the final call. Keep the fixed reference values in view: 70%, 190, 60, 151, 133.
Does this work in miles and kilometers?
Yes. PacerRunning is written for US runners first, so miles are easy to use, but metric conversions are kept alongside them where the tool needs both views.
Why might my real-world result differ?
Terrain, wind, heat, sleep, fueling, training fatigue, and measurement error can all move the real outcome away from the estimate. The Heart Rate Zone heart rate zone calculator cannot see those details. Keep the fixed reference values in view: 220, 10–20.
Can beginners use it?
Yes. You do not need advanced training knowledge. Enter the numbers you know, read the result as a guide, and keep your effort comfortable when you are unsure. Keep the fixed reference values in view: 40, 60, 70.
Can competitive runners use it too?
Yes. Faster runners can use the same output to check pacing, compare workouts, and keep training zones aligned with a recent performance. Keep the fixed reference values in view: 2, 60–70%.
Is this professional advice?
No. The result is general information for training and planning. For medical concerns, injury questions, nutrition treatment, or a personal race plan, work with a qualified professional.
When should I use the heart rate zone calculator?
Use it when you want a fast planning number before a run, race, workout, or gear decision. It gives you a consistent estimate without asking you to create an account.
Heart Rate Zone Calculator results are estimates from the entered data and the cited method. They are useful for planning and comparison, but they are not a diagnosis, prescription, guaranteed race result, or substitute for a coach or clinician.