Target Heart Rate Zones Calculator for Smarter Cardio Training
Compute personalized heart rate zones
Heart rate zones: quick guide
This calculator produces five practical training zones. You can calculate zones as a percentage of maximum heart rate, or use the Karvonen approach which works from heart rate reserve, the difference between maximum and resting. The second option often matches how workouts feel because it accounts for your personal resting value. If you know your laboratory or field-tested maximum, choose the custom option; otherwise select an age-based estimate.
Use the zones to pace steady runs, spin sessions, and recovery days. Zone 1 is very easy, conversational; Zone 2 is aerobic endurance; Zone 3 is moderate tempo; Zone 4 is threshold; Zone 5 is short, hard efforts. For most general fitness, most minutes land in Zones 1–2 with sprinkles of faster work. Competitive athletes periodize volume and intensity across the season.
- Warm up for 5–10 minutes before targeting a zone.
- Hydration, heat, and fatigue shift heart rate day to day.
- Wrist sensors lag on intervals; chest straps respond faster.
If you take medications that affect heart rate or have cardiovascular conditions, follow clinical guidance instead of generic percentages. Perceived exertion and talk-test cues remain valuable: if you can say full sentences you are likely in Zones 1–2; short phrases point to Zone 3–4; single words suggest Zone 5. Mix tools to steer effort intelligently.
How the heart rate zones are calculated
The calculator first determines your maximum heart rate. If you choose an estimate, it uses either the familiar 220 minus age or the Tanaka alternative 208 minus 0.7 times age. If you provide a custom maximum, that overrides the estimate. Next, pick whether zones are based on a straight percentage of maximum, or on heart rate reserve using the Karvonen method which adds the chosen percentage of reserve back to your resting value.
- Zones by percent of Max HR:
- Zone 1: 50–60%
- Zone 2: 60–70%
- Zone 3: 70–80%
- Zone 4: 80–90%
- Zone 5: 90–100%
- Karvonen formula:
Target = Resting + % × (Max − Resting)
The output lists each zone with a low and high value. You can display results as beats per minute or as beats per second for contexts where Hertz is preferred, but bpm is the common choice for consumers and wearables.
Heart rate zone FAQs
Which max heart rate formula should I use?
Age-based formulas are rough guides. If you have a reliable lab test or a hard, recent field test, use the custom option for tighter zones.
Why do my numbers vary day to day?
Heat, dehydration, altitude, sleep, caffeine, and stress all influence heart rate. Treat zones as bands, not single points.
Is Karvonen better?
Many athletes prefer it because it accounts for resting heart rate. If your resting value is unusually low or high, Karvonen can feel more accurate.
Do I need a chest strap?
Wrist sensors are convenient but can lag on surges. For intervals and thresholds, a strap improves responsiveness.
Can beginners train in Zone 3?
Yes in small doses, but build most minutes in Zones 1–2 first to develop durable aerobic capacity and reduce injury risk.