Target Heart Rate Calculator
Estimate maximum heart rate, heart-rate reserve and personalized training zones using several evidence-informed formulas.
Your Information
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Your target zones
How the calculator works
The tool first estimates or accepts your maximum heart rate. When a resting heart rate is supplied, the Karvonen method uses heart-rate reserve to personalize each zone. Without a resting value, the tool can calculate zones directly from a percentage of maximum heart rate.
Target HR = RHR + (Intensity × HRR)
For example, at 70% intensity with MHR 184 and RHR 65, HRR is 119 and the Karvonen target is about 148 bpm.
Heart-rate training zones
Zone 1 · 50–60% Easy effort, warm-up and recovery.
Zone 2 · 60–70% Comfortable aerobic work and endurance building.
Zone 3 · 70–80% Moderate-to-hard sustained aerobic training.
Zone 4 · 80–90% Hard work, commonly used for intervals and performance training.
Zone 5 · 90–100% Very hard effort, generally used for short intervals.
Target Heart Rate Calculator Guide
Heart rate is one practical way to monitor exercise intensity. Target heart rate means a range of beats per minute used as a training reference. This DigiSadhan calculator is designed to make the calculation transparent rather than presenting one number as a medical fact.
Maximum heart rate
A measured maximum heart rate from a properly supervised test can be more individualized than an age equation. When a measured value is unavailable, this tool offers three common equations: Haskell & Fox (220 − age), Tanaka (208 − 0.7 × age), and Nes (211 − 0.64 × age). Calculator.net documents these approaches and notes that maximum-heart-rate formulas can vary substantially from one person to another.
Karvonen method
The Karvonen method uses resting heart rate as well as maximum heart rate. First calculate heart-rate reserve: MHR minus RHR. Then multiply that reserve by the desired intensity and add resting heart rate. This can produce a more individualized training range than simply taking a percentage of maximum heart rate because it accounts for the user's resting baseline.
Why resting heart rate matters
Resting heart rate is best measured when you are calm and rested. A single reading can be affected by stress, illness, caffeine, dehydration, temperature and recent exercise. For training purposes, consistency in how you measure it is often more useful than chasing one perfect number.
RPE as a second check
Heart rate is not the only way to judge intensity. The CDC describes relative effort on a 0–10 scale, with moderate intensity around 5–6 and vigorous intensity around 7–8. The calculator therefore includes an RPE option so users can compare a numerical heart-rate target with how hard the workout actually feels.
Five zones
The five-zone model divides intensity into broad percentage ranges. These zones are useful training labels, not universal physiological boundaries. Zone 2, for example, is often used for easier aerobic endurance work, while Zones 4–5 are typically reserved for harder efforts and intervals.
What can change heart rate?
Heat, humidity, altitude, hydration, sleep, stress, medication, illness and caffeine can affect heart rate. The same pace can therefore produce different heart rates on different days. Use the number as a guide and pay attention to symptoms and perceived effort.
Using a wearable
A chest strap, optical wrist sensor or manual pulse check can provide heart-rate data. Devices differ in accuracy and can lose signal during movement. If your device and calculated zone disagree, consider the quality of the measurement before changing your entire workout.
Adults and general fitness
For general health, the CDC recommends adults accumulate at least 150 minutes of moderate-intensity aerobic activity per week, or 75 minutes of vigorous activity, plus muscle-strengthening activity on at least two days. Target heart rate can help with intensity awareness, but a complete fitness plan should include recovery and a variety of activities.
Safety
This calculator is educational and does not diagnose heart disease or prescribe exercise intensity. People with cardiovascular disease, symptoms during exercise, or medical restrictions should obtain individualized advice from an appropriate clinician. Stop exercise and seek urgent medical attention for severe chest pain, fainting, severe breathlessness or other emergency symptoms.
Why DigiSadhan shows several methods
No age-based maximum-heart-rate formula is exact for every person. Showing three formulas lets users see the effect of the selected model. If you have a reliable measured maximum heart rate, entering it can avoid relying on an age-based estimate.
Practical example
Suppose a 35-year-old has a resting heart rate of 65 bpm. Tanaka estimates MHR at 183.5 bpm, which is rounded for display. HRR is then about 118.5. At 60%, 70%, 80% and 90% Karvonen intensity, the resulting targets are calculated from the same reserve. The calculator performs these steps automatically and shows them in the audit section.
Limitations
Target heart-rate ranges are estimates. They should not be interpreted as exact thresholds for fat burning, aerobic fitness, lactate, VO₂ max or medical risk. Individual physiology varies, and the most appropriate intensity can depend on training goals, medications and health status.
FAQ
Which maximum-heart-rate formula should I use?
Tanaka is the default because it is widely used in adult fitness contexts, but no age equation is exact for every person. If you have a valid measured maximum, entering it is preferable to an age estimate.
What if I don't know my resting heart rate?
Use the % Maximum HR method. The Karvonen method specifically needs resting heart rate.
Can I use this for medical decisions?
No. It is an educational fitness calculator and is not a diagnostic or treatment tool.