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Target Heart Rate Calculator

Calculate heart rate zones for effective exercise

Age 25 years
yrs
Resting Heart Rate (optional) 60 bpm
bpm
Measure first thing in the morning before getting up. Used for Karvonen method.
Formula

What is Target Heart Rate and Why Does it Matter?

When you exercise, your heart beats faster to pump more blood and oxygen to working muscles. The intensity of your workout directly determines how fast your heart beats โ€” and different heart rate zones produce different fitness benefits. Exercising at the right heart rate zone for your goal is the difference between an effective workout and one that's either too easy or too hard to sustain.

Target heart rate zones are expressed as percentages of your maximum heart rate (MHR). Your MHR is roughly the fastest your heart can beat. It decreases with age โ€” a 20-year-old's MHR is about 200 bpm while a 60-year-old's is around 160 bpm.

Maximum Heart Rate Formula

The most widely used formula is simple:

Maximum Heart Rate = 220 โˆ’ Age
Example: For a 30-year-old: MHR = 220 โˆ’ 30 = 190 bpm

This formula has been around since the 1970s and while it's a good starting point, it has a margin of error of about ยฑ10-12 bpm. A more accurate formula for older adults is the Tanaka formula: MHR = 208 โˆ’ (0.7 ร— age). Our calculator uses the standard 220-minus-age formula as it's most widely used and understood.

The 5 Heart Rate Training Zones

Zone 1 โ€” Very Light (50-60% MHR): Warm-up and cool-down zone. Very easy effort, you can hold a full conversation. Good for recovery days and building basic aerobic base in beginners.

Zone 2 โ€” Fat Burning (60-70% MHR): The famous fat-burning zone. At this intensity, your body uses a higher proportion of fat as fuel compared to carbohydrates. Great for long steady walks, easy cycling, light jogging. This is the zone most beginners should spend the most time in.

Zone 3 โ€” Aerobic (70-80% MHR): Moderate intensity cardio. Breathing is harder, you can still talk but in short sentences. Improves cardiovascular efficiency and endurance. This is a typical "comfortable but challenging" workout zone.

Zone 4 โ€” Anaerobic (80-90% MHR): High intensity. You can only speak a few words. Builds speed, power and increases lactate threshold. HIIT workouts typically involve repeated bursts into this zone.

Zone 5 โ€” Maximum (90-100% MHR): All-out effort, unsustainable for more than a few minutes. Reserved for trained athletes during peak performance intervals. Not recommended for general fitness or beginners.

Karvonen Method โ€” The More Accurate Way

The Karvonen or Heart Rate Reserve method accounts for your resting heart rate (RHR), giving more personalized zones. Heart Rate Reserve = MHR โˆ’ RHR. Target HR = RHR + (HRR ร— intensity%).

For example, a 30-year-old with an RHR of 60 bpm: MHR = 190, HRR = 130. For 70% intensity: Target HR = 60 + (130 ร— 0.70) = 151 bpm. Compare this to the simple method: 190 ร— 0.70 = 133 bpm. Quite a difference, especially for people with low resting heart rates like trained athletes.

How to Measure Your Resting Heart Rate

Measure RHR first thing in the morning before getting out of bed. Count your pulse for 60 seconds (or 30 seconds and double it). Do this for 3 consecutive mornings and take the average for accuracy. Normal RHR is 60-100 bpm. Athletes often have RHR of 40-60 bpm โ€” a lower RHR generally indicates better cardiovascular fitness.

What heart rate should I maintain for weight loss?
Zone 2 (60-70% of MHR) is called the fat-burning zone because at this intensity a higher percentage of calories come from fat. However, total calorie burn matters more than fat percentage. Higher intensity exercise burns more total calories in less time. A mix of Zone 2 steady cardio and some Zone 4 HIIT is typically most effective for fat loss.
My heart rate goes very high even during light exercise โ€” is that normal?
If your heart rate shoots up disproportionately during light activity, it could indicate deconditioning (being out of shape), dehydration, anaemia, thyroid issues or cardiac conditions. Start slowly and build fitness gradually. If your resting heart rate is consistently above 100 bpm or you experience dizziness or chest discomfort during exercise, see a doctor before continuing.
Is it safe to exercise in Zone 4 or 5?
Zone 4-5 training is safe for healthy, conditioned individuals. However, beginners and those with cardiovascular conditions should stick to Zones 1-3 until they build a solid aerobic base. Always get medical clearance before starting high-intensity exercise if you are over 40, overweight, or have any health conditions.
Do heart rate zones change as I get fitter?
Yes. As you get fitter, your resting heart rate decreases and your heart becomes more efficient. The same absolute heart rate (say 140 bpm) will represent a lower percentage of your MHR over time, feeling easier. Recalculate your zones every few months and update your resting heart rate to keep your training zones accurate.