heart rate training calculator

What this heart rate training calculator does

A heart rate training calculator helps you find practical workout intensity ranges, usually called training zones. Instead of guessing how hard to run, cycle, row, or walk, you can use your heart rate as a guide. This is useful for beginners and experienced athletes alike, because most plans work best when easy days are truly easy and hard days are intentionally hard.

The calculator above uses the Karvonen (Heart Rate Reserve) approach, which accounts for your resting heart rate. That usually makes zones more personalized than using age alone.

How the calculation works

1) Maximum Heart Rate (Max HR)

If you already know your measured max heart rate from a supervised field test or lab test, enter it. If not, the calculator estimates it using one of two common formulas:

• Fox: 220 − age
• Tanaka: 208 − (0.7 × age)

2) Heart Rate Reserve (HRR)

Heart Rate Reserve is the gap between your max and resting values:
HRR = Max HR − Resting HR

3) Zone Targets (Karvonen Formula)

For each zone, target heart rate is calculated as:
Target HR = Resting HR + (% intensity × HRR)

This produces a lower and upper heart-rate boundary for each training zone.

Training zones explained

• Zone 1 (50–60%): Recovery pace. Great for warm-ups, cool-downs, and easy movement.
• Zone 2 (60–70%): Aerobic endurance. Builds your base and supports long-term fitness.
• Zone 3 (70–80%): Moderate/tempo. Improves sustained effort and stamina.
• Zone 4 (80–90%): Threshold work. Challenging efforts that raise your performance ceiling.
• Zone 5 (90–100%): Very hard intervals. Short, intense sessions for speed and VO₂ development.

How to use your zones each week

Most people improve best when the majority of training is easy, with limited high-intensity work. A simple framework is:

• Most sessions in Zone 1–2 for aerobic development and recovery.
• 1–2 focused quality workouts in Zone 3–5, depending on your experience.
• At least one easy or rest day after very hard sessions.

Accuracy tips

• Measure resting heart rate first thing in the morning for several days and average it.
• Use a chest strap for better accuracy during intervals and hill work.
• Heat, stress, dehydration, altitude, and caffeine can raise heart rate.
• Re-test every 6–8 weeks as your fitness changes.

Important safety note

This calculator is an educational tool, not medical advice. If you have cardiovascular, metabolic, or respiratory conditions—or are returning to exercise after a long break—consult a qualified healthcare professional before starting intense training.