What is the Karvonen formula?

The Karvonen formula calculates target heart rate as: RestingHR + (Intensity × HeartRateReserve), where HeartRateReserve = MaxHR − RestingHR. It accounts for individual fitness level through resting heart rate, making it more personalized than simple percentage-of-max methods.

How do I measure my resting heart rate?

Measure it first thing in the morning before getting out of bed. Count beats for 60 seconds, or count for 15 seconds and multiply by 4. Take readings on three consecutive days and average them for best accuracy. A typical resting HR is 60–80 BPM; trained athletes often fall below 60.

How do I find my true maximum heart rate?

The most accurate method is a graded exercise test (stress test) in a lab. A field estimate is a maximal effort run or bike — the highest reading you see during an all-out effort. The formula 220 − age is a population average with ±10–20 BPM individual variation, so use a real test if precision matters.

Why is the Karvonen method better than percentage of max HR?

Percentage-of-max ignores resting HR, so two people with the same max HR but different fitness levels get identical targets. Karvonen accounts for your actual working capacity (the heart rate reserve), so a highly trained athlete with a low resting HR gets appropriately higher absolute targets than a sedentary person.

What are the five training zones?

Zone 1 (50–60%): active recovery and warm-up. Zone 2 (60–70%): aerobic base and fat burning. Zone 3 (70–80%): aerobic development and tempo. Zone 4 (80–90%): lactate threshold and race pace. Zone 5 (90%+): VO2max and maximal effort intervals.

Karvonen Formula

Enter your resting heart rate and max heart rate to get Karvonen training zones from Zone 1 (50%) to Zone 5 (90%).

Heart Rate Inputs

Resting Heart Rate (BPM)

Measured lying down, before getting up in the morning.

Maximum Heart Rate (BPM)

From a lab test or hard field effort. Or use the estimator below.

Estimate Max HR from Age

Training Zones

Heart Rate Reserve: — BPM

Enter your values and click Calculate Zones.

Summary

The Karvonen formula calculates target heart rate training zones using the heart rate reserve (HRR) method. Unlike simple percentage-of-max approaches, it factors in your resting heart rate to produce zones tailored to your individual fitness level. Enter your resting HR and max HR to instantly see BPM ranges for five zones from easy recovery to maximal effort.

How it works

Enter your resting heart rate (measured after waking, before getting up).
Enter your maximum heart rate (from a lab test or use 220 minus age as an estimate).
The calculator computes your Heart Rate Reserve (HRR = MaxHR − RestingHR).
Each zone target HR = RestingHR + (Intensity% × HRR).
Results show the BPM range for five training zones.

Use cases

Set accurate heart rate zones on a GPS watch or heart rate monitor.
Plan aerobic base-building workouts in Zone 2 without overtraining.
Identify anaerobic threshold zones for interval training.
Compare Karvonen zones against percentage-of-max-HR zones.
Adjust zones after fitness improves and resting HR drops.
Coach clients by giving them personalized BPM targets for each session.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu