Heart Rate Calculator
Enter your age and resting heart rate. You can also enter your measured maximum heart rate for more accurate results.
Lightest zone. Ideal for warm-ups, cool-downs, and active recovery.
Most effective zone for fat burning. Improves aerobic endurance and metabolism.
Improves aerobic capacity and muscular endurance. Good for longer training sessions.
Heavy zone. Improves speed endurance and lactate threshold.
Maximum performance. Used for interval training and speed work.
Heart Rate Calculator – Training Zone Calculator
The heart rate calculator determines your five personalized training zones using the Karvonen formula, which factors in both maximum heart rate and resting heart rate. Training in the right heart rate zone maximizes results while minimizing injury risk and overtraining.
The Karvonen Formula
The Karvonen method calculates target heart rates using Heart Rate Reserve (HRR) — the difference between your maximum and resting heart rate:
Target HR = Resting HR + (Heart Rate Reserve × Intensity %)
Heart Rate Reserve = Max HR − Resting HR
This formula provides more individualized zones than simply using a percentage of maximum heart rate because it accounts for your fitness level (reflected in your resting heart rate).
Worked Example
A 35-year-old with a resting heart rate of 65 BPM:
- Estimated Max HR: 220 − 35 = 185 BPM
- Heart Rate Reserve: 185 − 65 = 120 BPM
- Zone 2 (60–70%): 65 + (120 × 0.60) to 65 + (120 × 0.70) = 137–149 BPM
- Zone 4 (80–90%): 65 + (120 × 0.80) to 65 + (120 × 0.90) = 161–173 BPM
Maximum Heart Rate Estimation
The most widely used formula is 220 − age, but several alternatives exist for different populations:
| Formula | Equation | Best For |
|---|---|---|
| Fox (standard) | 220 − age | General population |
| Tanaka (2001) | 208 − (0.7 × age) | Adults, more accurate for older adults |
| Gulati (2010) | 206 − (0.88 × age) | Women specifically |
| Gellish (2007) | 207 − (0.7 × age) | Active adults |
All formulas are estimates — actual max HR can vary by ±10–20 BPM between individuals of the same age. The most accurate way to determine your max HR is a graded exercise test supervised by a medical professional.
The Five Heart Rate Training Zones
| Zone | Intensity | Feel | Primary Benefit | Duration |
|---|---|---|---|---|
| Z1 – Recovery | 50–60% | Very easy | Active recovery, warm-up | 30–60 min |
| Z2 – Aerobic Base | 60–70% | Easy, conversational | Fat burning, endurance | 60–180 min |
| Z3 – Aerobic Power | 70–80% | Moderate effort | Aerobic capacity, stamina | 30–60 min |
| Z4 – Threshold | 80–90% | Hard, can speak a few words | Lactate threshold, speed | 10–30 min |
| Z5 – Maximum | 90–100% | All-out effort | VO₂max, anaerobic power | 1–5 min intervals |
Resting Heart Rate Reference
Your resting heart rate is an important indicator of cardiovascular fitness:
| Resting HR (BPM) | Classification |
|---|---|
| Below 40 | Elite athlete |
| 40–50 | Well-trained athlete |
| 51–60 | Very fit |
| 61–70 | Fit / above average |
| 71–80 | Average |
| 81–100 | Below average |
| Above 100 | Consult a physician (tachycardia) |
How to measure: Take your pulse first thing in the morning before getting out of bed. Count beats for 60 seconds, or count for 30 seconds and multiply by 2. Average across 3–5 days for the most reliable result.
Training Tips by Zone
- 80% of training in Zone 2 — The "80/20 rule" suggests 80% of your weekly training should be easy (Zone 1–2) and 20% hard (Zone 4–5). This approach builds a strong aerobic base while allowing adequate recovery.
- Zone 2 for weight loss — While Zone 2 burns a higher percentage of fat, higher-intensity zones burn more total calories per minute. Both are effective for weight management.
- Zone 4 for race performance — Threshold training (tempo runs, lactate intervals) teaches your body to sustain faster paces and delay fatigue.
- Zone 5 sparingly — High-intensity intervals (HIIT) are powerful for VO₂max improvement but require 48+ hours of recovery. Limit to 1–2 sessions per week.
Frequently Asked Questions
What is my maximum heart rate?
The most common estimate is 220 minus your age. For a 30-year-old, estimated max heart rate is 190 BPM. The actual value can vary by 10–20 BPM between individuals. A supervised exercise stress test provides the most accurate measurement.
What heart rate zone burns the most fat?
Zone 2 (60–70% of max HR) is called the 'fat-burning zone' because a higher percentage of calories come from fat. However, higher-intensity zones burn more total calories per minute, making both approaches effective for weight loss.
What is the Karvonen formula?
The Karvonen formula calculates target heart rate using Heart Rate Reserve (max HR minus resting HR). Formula: Target HR = Resting HR + (HR Reserve × desired intensity %). This gives more personalized zones than using percentage of max HR alone.
What is a healthy resting heart rate?
For adults, a normal resting heart rate is 60–100 BPM. Athletes typically have lower resting rates (40–60 BPM) due to a more efficient cardiovascular system. Consistently above 100 BPM at rest (tachycardia) warrants medical attention.
How should I measure my resting heart rate?
Measure first thing in the morning before getting out of bed. Count beats for 60 seconds, or count for 30 seconds and double the result. Average over 3–5 days for the most accurate reading.
Related Tools
- Calorie Burn Calculator — Calculate calories burned during exercise
- Running Pace Calculator — Calculate pace, speed, and finish times
- BMI Calculator — Check your Body Mass Index
- BMR Calculator — Find your Basal Metabolic Rate
- Daily Calorie Needs Calculator — Determine your daily calorie target