Don't just work out harder—work out smarter. Find your precision heart rate zones and reach your goals faster, whether you're finishing your first 5K or chasing a new PR.
For best results, check your pulse for 60 seconds immediately after waking up, before getting out of bed.
Leave resting HR blank to use the standard 60 bpm estimate. Measure your resting HR first thing in the morning for best accuracy.
Max heart rate
—bpm
Heart rate reserve
Your heart rate reserve is the difference between your maximum (peak) heart rate and your resting heart rate.
—bpm
Your training zones
What is the Karvonen Formula?
The Karvonen method (also called the Heart Rate Reserve method) calculates your target training zones more accurately than the simple percentage-of-max approach because it factors in your individual resting heart rate.
Target HR = Resting HR + (Intensity% × (Max HR − Resting HR))
Max HR = 220 − Age
Heart Rate Reserve (HRR) = Max HR − Resting HR
Understanding Your Zones
Zone 1 (50–60%) — Active recovery and warm-up. Very easy effort, ideal for rest days and building aerobic foundation.
Zone 2 (60–70%) — Aerobic base building and fat burning. The "conversational" pace. Most of your training should be here.
Zone 3 (70–80%) — Aerobic endurance. Moderate effort that improves cardiovascular efficiency and stamina.
Zone 4 (80–90%) — Lactate threshold training. Hard, sustainable effort that raises your anaerobic threshold over time.
Zone 5 (90–100%) — Maximum effort. Short, all-out intervals for peak speed and power. Use sparingly.
Why Use the Karvonen Formula?
Most heart rate calculators give everyone the same zones. The Karvonen method gives you yours — calibrated to your actual cardiovascular fitness, not just your age.
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Precision over guesswork
By factoring in your resting heart rate, Karvonen zones shift as you get fitter — so your Zone 2 run stays genuinely easy, not secretly hard.
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Maximize fat burning
Training in the wrong zone is the #1 reason people plateau. A personalized Zone 2 keeps you in the fat-oxidation window — not the sugar-burning stress zone.
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Protect your recovery
Generic calculators routinely prescribe Zone 3 as "easy." For a fit athlete with a low resting HR, that's overtraining. Karvonen keeps easy days actually easy.
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Track real progress
As your cardiovascular fitness improves, your resting HR drops. Recalculate monthly and watch your zones shift — a built-in progress metric that doesn't lie.
Karvonen Method
Heart Rate Reserve
Accounts for resting HR
Adapts as you get fitter
Reflects true cardiovascular load
Used by coaches & sports scientists
VS
Simple % of Max HR
Age-Only Formula
Ignores individual fitness
Static — never updates
Same zones for everyone
Up to 15 bpm off for fit athletes
Who benefits most?
🏃 Runners🚴 Cyclists🏊 Triathletes🏋️ Strength athletes❤️ Cardiac rehab patients🧘 Anyone wearing a HR monitor📉 Weight loss seekers🩺 Longevity-focused individuals