Target Heart Rate Calculator
Personalize training zones using the heart rate reserve (Karvonen) method. Use an age-based estimate or enter a tested maximum.
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How to use target heart rate zones
Target heart rate zones are a practical way to pace workouts without needing a lab. By combining an estimate of your maximum heart rate with your resting heart rate, the calculator shows intensities matched to common training goals. The approach here uses the Karvonen method, which scales training effort to your heart rate reserve (maximum minus resting). That keeps zones personal: two people with the same maximum can still have different resting values, so their working ranges differ.
What each input means
- Age: If you don’t have a tested maximum, age lets the calculator estimate it using a formula. The default is the classic 220 − age; you can also choose Tanaka’s 208 − 0.7 × age.
- Max heart rate: If you’ve done a medically appropriate test (or have recent race data that pushed to the limit), enter that value directly for the most personalized zones.
- Resting heart rate (optional): First thing in the morning is ideal. If you skip it, the calculator assumes 70 bpm to keep results usable and flags the assumption under the table.
How the calculator works
The Karvonen method computes target beats per minute (bpm) as RHR + % × (MaxHR − RHR). For example, at 70% of heart rate reserve with a resting heart rate of 60 bpm and a maximum of 190 bpm: reserve is 130 bpm; 70% is 91 bpm; add resting to get about 151 bpm.
Choosing a zone
- Very light (50–60% HRR): Easy recovery, gentle movement, and getting started.
- Light (60–70% HRR): Conversational endurance work; most base miles live here.
- Moderate (70–80% HRR): Steady efforts and tempo sessions that feel “comfortably hard.”
- Hard (80–90% HRR): Shorter intervals and race-specific work with long rests.
- VO₂ max (90–100% HRR): Maximal-effort intervals for advanced trainees.
Tips for accuracy
- Use the same device and placement each time; chest straps are usually most precise.
- Warm up 10–15 minutes before judging how a zone feels on a given day.
- Heat, dehydration, caffeine, illness, and poor sleep all raise heart rate at a given effort.
Safety notes
High-intensity training is stressful by design. If you take heart-rate-affecting medications, are returning from illness or injury, or have cardiovascular risk factors, discuss an appropriate plan with your clinician. Never ignore symptoms like chest pain, severe shortness of breath, or dizziness.
Putting it together
Use one or two primary zones for most sessions and rotate a harder day only as recovery allows. Pair heart rate with your breathing rhythm or a simple rating of perceived exertion so you can keep pacing even when sensor readings wobble. Review weekly averages rather than one workout, and expect zones to drift as you get fitter, lose or gain weight, or the weather changes. Re-measure resting heart rate occasionally and revisit the calculator after a few months.
Informational use only; not medical advice. Stop any session that feels unsafe and seek care if needed.
Target Heart Rate Calculator — FAQ
What is a target heart rate?
Your target heart rate (THR) is a training range—usually a percentage of your maximum heart rate—used to guide workout intensity for specific goals like endurance, fat loss, or speed.
How do I estimate my maximum heart rate?
The common estimate is 220 − age. A research alternative is Tanaka: 208 − 0.7 × age. The calculator can use either approach to build your zones.
What are heart rate “zones”?
Zones are intensity bands (e.g., Zone 2 = ~60–70% of max). Typical ranges: Zone 1 (50–60%), Zone 2 (60–70%), Zone 3 (70–80%), Zone 4 (80–90%), Zone 5 (90–100%).
Which method should I use—% of Max or the Karvonen method?
% of Max is simple (percent of MHR). Karvonen uses heart-rate reserve: (Max − Resting) × % + Resting. Karvonen personalizes zones if you know your resting HR.
Which zone is best for fat loss vs endurance?
Many use Zone 2 for steady aerobic work and fat oxidation; Zones 3–4 for tempo/threshold; Zone 5 for short, high-intensity efforts. Mix zones across a week to match your goals and fitness.
Is 220 − age accurate for everyone?
No. It’s a convenient estimate; individual max heart rates vary. If you have lab results, a recent field test, or a medical recommendation, use those instead.
How long should I stay in a given zone?
It depends on the workout: recovery (Zone 1) can be 10–40 minutes, Zone 2 base runs/rides 30–120+ minutes, threshold intervals (Zone 4) a few to several minutes, Zone 5 15–90 seconds per rep.
Do medications affect target heart rate?
Yes. Beta-blockers and other meds can lower heart rate response. Always follow medical guidance and use perceived effort or power/pace as additional guides.
Use cases & worked examples
Example 1 — 30-year-old runner (simple % of Max)
Estimated Max HR (220 − age) = 220 − 30 = 190 bpm.
Zone 2 (60–70%): 0.60 × 190 = 114 bpm to 0.70 × 190 = 133 bpm.
Zone 4 (80–90%): 152–171 bpm; Zone 5 (90–100%): 171–190 bpm.
Use Zone 2 for aerobic base and easy days; reserve Zones 4–5 for quality workouts and racing.
Example 2 — 30-year-old with Resting HR = 55 bpm (Karvonen method)
Max HR = 190, Resting HR = 55, Heart-rate reserve = 190 − 55 = 135.
Zone 2 (60–70%):
Lower = (135 × 0.60) + 55 = 81 + 55 = 136 bpm
Upper = (135 × 0.70) + 55 = 94.5 + 55 = 149.5 ≈ 150 bpm
Karvonen personalizes zones by factoring in your resting HR. If you know it (e.g., from morning readings), this method can be more precise.
Example 3 — 55-year-old beginner
Estimated Max HR (220 − 55) = 165 bpm.
Zone 2 by % of Max (60–70%): 99–116 bpm.
With Resting HR ≈ 65 bpm (Karvonen Zone 2): (165 − 65) × (0.60–0.70) + 65 → 125–135 bpm.
Start with mostly Zone 1–2 for several weeks, then add short bouts of Zone 3+ as fitness and comfort improve.
Training guidance is general information and not medical advice. If you have heart, blood-pressure, or other medical conditions, consult a qualified professional before following heart-rate-based training.