Heart Rate Calculator Guide
A heart rate calculator estimates training zones from your age and resting heart rate. Use either a percent of max approach or the Karvonen method (heart rate reserve) to tailor intensities to your fitness.
What is Heart Rate Calculator?
The heart rate calculator outputs zones for easy, aerobic, tempo, threshold, and interval work. It helps plan safe, effective sessions for running, cycling, and general cardio.
How to Use the Heart Rate Calculator
- Enter age and optionally resting HR (RHR).
- Choose method: straight % of MHR or Karvonen.
- Calculate Zones 1-5 (and custom bands).
- Apply zones to plan workouts (warm-up, base, tempo, intervals).
- Reassess monthly as fitness or RHR changes.
Formulas & Methods
- Max heart rate (estimate):
MHR ~ 220 - age
(alternatives exist). - Percent-of-max zones:
Zone% x MHR
(e.g., Zone 2 ~ 60-70% MHR). - Karvonen:
HR_target = (HRR * intensity) + RHR
, whereHRR = MHR - RHR
. - Example zone bands (run):
Z1: 50-60%, Z2: 60-70%, Z3: 70-80%, Z4: 80-90%, Z5: 90-100% of MHR (or equivalent Karvonen).
Assumptions & limitations
- Zone formulas are population averages; individual thresholds vary.
- Medications and dehydration affect HR response; monitor symptoms.
- Use talk test and RPE alongside HR for better control.
Examples
Example A — Percent of max
Age 35
: MHR ~ 185
. Zone 2: 0.60-0.70 * 185 -> 111-130 bpm
.
Example B — Karvonen
Age 40
, RHR = 60
, MHR ~ 180
, HRR = 120
.
Zone 3 (70-80%): HR = 120*0.70 + 60 -> 144
to 120*0.80 + 60 -> 156 bpm
.
| Zone | % of MHR | Karvonen Example (bpm) | |---|---|---| | Z1 | 50-60% | 120-132 | | Z2 | 60-70% | 132-144 | | Z3 | 70-80% | 144-156 | | Z4 | 80-90% | 156-168 | | Z5 | 90-100% | 168-180 |
Pro Tips & Best Practices
- Measure resting HR on multiple mornings for stability.
- Recalibrate after fitness changes or heat acclimation.
- Use a chest strap for more accurate HR than wrist sensors.
- Combine HR with pace/power for endurance training.
Related Calculators
FAQ
Q: How do you calculate target heart rate zones?
A: We use a percentage of maximum heart rate (MHR) or the Karvonen method with heart rate reserve (HRR).
Q: What is my maximum heart rate?
A: A simple estimate is 220 - age. More refined formulas exist; actual MHR varies by individual.
Q: Karvonen vs straight percent?
A: Karvonen uses HRR = MHR - RestingHR, which personalizes zones to your resting fitness.
Q: How accurate are these zones?
A: They are estimates. Use perceived exertion and, if available, lab or field tests to calibrate.
Q: Is this medical advice?
A: No—consult your doctor before starting a new exercise program.
Health note: Informational only; not medical advice.
Call to Action
Enter your age (and resting HR) to generate zones—then build workouts that target the right intensity every time.