What is the Karvonen formula?

The Karvonen formula calculates target heart rate as: (Max HR − Resting HR) × intensity% + Resting HR. The difference between max and resting HR is called the Heart Rate Reserve (HRR). This method produces more individualized zones than simple percentage-of-max because it accounts for your current fitness level.

How is maximum heart rate estimated?

Two common formulas are used: the Tanaka formula (208 − 0.7 × age), based on a large meta-analysis and recommended for most adults, and the classic formula (220 − age). Both are estimates; a laboratory stress test provides the most accurate measurement.

How do I measure resting heart rate?

Measure it first thing in the morning before getting out of bed. Lie still for one to two minutes, then count your heartbeats for 60 seconds. A healthy adult resting HR is typically 60–100 bpm; trained athletes often see 40–60 bpm.

What are the five training zones?

Zone 1 (50–60% HRR) is warm-up and recovery. Zone 2 (60–70% HRR) is aerobic base and fat burning. Zone 3 (70–80% HRR) is moderate aerobic conditioning. Zone 4 (80–90% HRR) is anaerobic threshold and performance. Zone 5 (90–100% HRR) is maximum effort for short intervals.

Why is the Karvonen formula better than simple max HR percentage?

A simple percentage uses only max HR, ignoring individual differences in resting HR. Two people the same age can have very different resting HRs (e.g., 50 vs 80 bpm), meaning their cardiovascular systems are working differently at rest. The Karvonen formula corrects for this by using heart rate reserve, which reflects actual cardiac workload capacity.

Is resting heart rate required?

Yes, a resting heart rate input is required to apply the Karvonen formula. If you do not know your resting HR, a typical default for healthy adults is 70 bpm, but measuring it yourself will produce more accurate zones.

Target Heart Rate Calculator

Enter your age and resting heart rate to calculate personalized target heart rate zones using the Karvonen formula.

Your Details

Age *

yrs

Age 10 – 100 years

Resting Heart Rate *

bpm

Measured at rest, ideally on waking (30 – 120 bpm)

Max HR Formula

Tanaka is more accurate, especially for adults over 40

Enter your age and resting heart rate

Your Karvonen target zones will appear here

Please enter valid values.

Summary

Enter your age and resting heart rate to calculate personalized target heart rate zones using the Karvonen formula.

How it works

The calculator first estimates your maximum heart rate using either the Tanaka formula (208 − 0.7 × age) or the classic 220 − age formula. It then computes your Heart Rate Reserve (HRR = max HR − resting HR). Each target zone is calculated as: Target HR = (HRR × intensity%) + resting HR. Five zones range from 50% (warm-up) to 100% (maximum effort).

Use cases

Set accurate heart rate targets on a treadmill, stationary bike, or GPS watch.
Determine the correct intensity range for fat-burning, aerobic, or interval workouts.
Plan recovery runs by verifying you stay within low-intensity Zone 1 or Zone 2.
Design interval training sessions targeting Zone 4 or Zone 5 thresholds.
Track cardiovascular fitness improvement as resting HR decreases over time.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu