How to Calculate Your Target Heart Rate
Your heart rate during exercise is one of the most reliable indicators of how hard your body is working. Train at the right intensity for your goal and you get the adaptation you want. Train too easy and progress stalls. Train too hard for too long and recovery suffers.
This guide explains how to calculate your maximum heart rate, how to set your training zones and what each zone actually does. Use the free Target Heart Rate Calculator on CalConvs to find your zones instantly.
Maximum Heart Rate: The Starting Point
All heart rate training zones are expressed as percentages of your maximum heart rate (MHR), the highest number of times your heart can beat per minute.
Maximum Heart Rate Formula
Standard formula: MHR = 220 − age in years
Example (35-year-old): MHR = 220 − 35 = 185 bpm
More accurate formula for women: MHR = 206 − (0.88 × age)
Example (35-year-old woman): MHR = 206 − (0.88 × 35) = 175 bpm
These are population averages. Actual maximum heart rates vary by 10 to 15 beats per minute in either direction. The only way to know your true MHR precisely is a medically supervised exercise stress test.
The Five Heart Rate Training Zones
| Zone | Heart Rate Range | What It Does |
|---|---|---|
| Zone 1: Very light | 50 to 60% of MHR | Recovery, warm-up and cool-down. Full conversation possible. |
| Zone 2: Light | 60 to 70% of MHR | Fat burning. Builds aerobic base. Can speak in full sentences. |
| Zone 3: Moderate | 70 to 80% of MHR | Aerobic fitness. Improves cardiovascular efficiency. Short sentences only. |
| Zone 4: Hard | 80 to 90% of MHR | Lactate threshold training. Builds speed and power. Very hard to speak. |
| Zone 5: Maximum | 90 to 100% of MHR | Maximum effort. Used in HIIT. Impossible to sustain for more than seconds. |
Calculating Your Zones: A Worked Example
Heart Rate Zones for a 40-Year-Old
MHR = 220 − 40 = 180 bpm
Zone 1 (50 to 60%): 90 to 108 bpm
Zone 2 (60 to 70%): 108 to 126 bpm
Zone 3 (70 to 80%): 126 to 144 bpm
Zone 4 (80 to 90%): 144 to 162 bpm
Zone 5 (90 to 100%): 162 to 180 bpm
Which Zone Should You Train In?
| Goal | Best Zone |
|---|---|
| Burning fat | Zone 2 (60 to 70%). Fat provides the majority of energy. Best for longer sessions. |
| General cardiovascular fitness | Zone 3 (70 to 80%). Builds your aerobic engine most efficiently. |
| Speed and racing performance | Zone 4 (80 to 90%). Threshold training raises your lactate threshold. |
| HIIT and maximum intervals | Zone 5 (90 to 100%). Short bursts of 20 to 60 seconds followed by full recovery. |
| Recovery after a hard session | Zone 1 (50 to 60%). Easy movement promotes blood flow and reduces soreness. |
The Fat Burning Zone: A Common Misconception
Zone 2 is called the fat burning zone because at that intensity, fat provides a higher proportion of the energy used. However, this does not mean it burns the most total fat.
Higher intensity exercise burns more total calories per minute even though a lower percentage comes from fat. Over a 30-minute session, Zone 3 or Zone 4 training will burn more total calories and more total fat than Zone 2 for the same duration. The best approach for fat loss combines Zone 2 sessions for volume with higher intensity sessions 2 to 3 times per week.
The Karvonen Formula: A More Precise Method
The Karvonen formula uses your resting heart rate to create more personalised zones by calculating your heart rate reserve (HRR).
Karvonen Method: Age 40, MHR = 180, Resting HR = 60
Heart Rate Reserve (HRR) = MHR − Resting HR = 180 − 60 = 120
Target HR = (HRR × Intensity %) + Resting HR
Zone 2 lower bound (60%): (120 × 0.6) + 60 = 132 bpm
Zone 2 upper bound (70%): (120 × 0.7) + 60 = 144 bpm
These zones are higher than the simple percentage method because they account for the fit person's larger heart rate reserve.
How to Measure Heart Rate During Exercise
- A chest strap heart rate monitor is the most accurate option for real-time monitoring
- Wrist-based optical monitors on smart watches are convenient and accurate enough for most training purposes
- Manual pulse check: count beats at your wrist or neck for 15 seconds and multiply by 4
Related Tools
- Target Heart Rate Calculator: all five training zones calculated from your age
- Calorie Calculator: daily calorie needs to fuel your training
- TDEE Calculator: total energy expenditure including exercise
- All Health and Fitness Tools: browse all tools on CalConvs
Frequently Asked Questions
Is the 220 minus age formula accurate?
The 220 minus age formula is a population average and can vary by plus or minus 10 to 15 bpm for any individual. It tends to overestimate maximum heart rate for older adults and underestimate it for younger adults. For most recreational exercisers it provides a useful working estimate.
What is a good resting heart rate?
For most adults, a resting heart rate of 60 to 80 beats per minute is considered normal. A resting heart rate below 60 bpm is common in aerobically fit individuals and is generally healthy. A consistently elevated resting heart rate above 100 bpm warrants a medical check.
How do I use heart rate zones on a treadmill?
Most treadmills have grip-based heart rate sensors, though these are less accurate than chest straps or wrist-based monitors. Once you know your target zone, adjust speed and incline until your heart rate falls within the desired range. For Zone 2 training, many people are surprised how slow they need to go to stay in the zone initially.
Can I use heart rate training for cycling and swimming?
Yes, though your maximum heart rate is typically slightly lower for cycling than running and slightly lower again for swimming due to body position and water cooling effect. Many athletes use a sport-specific maximum heart rate for each discipline rather than a single number.