Quick answer
Karvonen target heart rate = (maximum − resting) × intensity + resting. With a resting rate of 60 and a maximum of 180 (208 − 0.7 × 40), training at 75% gives (120 × 0.75) + 60 = 150 bpm.
Enter resting heart rate, intensity and either your age or your measured maximum. The calculator returns the target rate, the heart rate reserve and the maximum. This page applies the Karvonen formula to your own resting and maximum heart rate.
Related tools: Max Heart Rate Calculator: Maximum heart rate and Karvonen training zones.
How to use the Karvonen Formula Calculator
- Optionally, enter age (used if no maximum is given) (a whole number, between 10 and 100).
- Optionally, enter maximum heart rate (bpm) (between 100 and 250).
- Enter resting heart rate (bpm) (between 30 and 120).
- Enter intensity (%) (between 0 and 100).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Age (used if no maximum is given) (optional) | A whole number | ≥ 10, ≤ 100 |
| Maximum heart rate (bpm) (optional) | A number | ≥ 100, ≤ 250 |
| Resting heart rate (bpm) | A number | ≥ 30, ≤ 120 |
| Intensity | A number, in % | > 0, ≤ 100 |
Formula and method
Formula
target = (HRmax − HRrest) × intensity + HRrest; HRmax = 208 − 0.7 × age when not given
IEEE-754 double precision; shown to the decimals indicated.
The heart-rate-reserve method; the age-based maximum uses the Tanaka equation. Informational estimate, not medical advice. Talk to a qualified health professional about your own situation.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Resting heart rate (bpm) = 60; Intensity = 75; Age (used if no maximum is given) = 40.
| Result | Value |
|---|---|
| Target heart rate | 150 |
| Heart rate reserve | 120 |
| Maximum heart rate | 180 |
Example 2
Inputs: Resting heart rate (bpm) = 55; Intensity = 60; Maximum heart rate (bpm) = 190.
| Result | Value |
|---|---|
| Target heart rate | 136 |
| Heart rate reserve | 135 |
| Maximum heart rate | 190 |
Example 3
Inputs: Resting heart rate (bpm) = 50; Intensity = 85; Age (used if no maximum is given) = 25.
| Result | Value |
|---|---|
| Target heart rate | 169 |
| Heart rate reserve | 141 |
| Maximum heart rate | 191 |
The first line is the headline result (target heart rate). Below it the karvonen Formula Calculator lists heart rate reserve and maximum heart rate, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Heart rate reserve
Reserve is maximum minus resting heart rate: 180 − 60 = 120. Karvonen training targets use a share of this reserve above your resting rate, so two people with the same age but different fitness get different zones.
Which maximum to use
If you have not measured your maximum, the calculator estimates it as 208 − 0.7 × age. A measured value from a supervised test is more reliable. Zones from this formula are a planning guide and should not replace medical advice.
How the result changes with age
Holding every other input at the first worked example, this table changes only age. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Age | Target heart rate | Heart rate reserve | Maximum heart rate |
|---|---|---|---|
| 20 | 161 | 134 | 194 |
| 40 | 150 | 120 | 180 |
| 80 | 129 | 92 | 152 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Age (used if no maximum is given): left empty shows "Enter your age or your maximum heart rate." beside that field and no result.
- Resting heart rate (bpm): entering "300" shows "Resting heart rate (bpm) must be at most 120." beside that field and no result.
Choosing between the Karvonen Formula Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Mean Arterial Pressure Calculator](/health/mean-arterial-pressure/) | systolic and diastolic | Mean arterial pressure |
| [LDL Cholesterol Calculator (Friedewald)](/health/ldl/) | total cholesterol, hDL cholesterol and triglycerides | Estimated LDL |
| [Max Heart Rate Calculator](/health/max-heart-rate/) | age | Maximum heart rate (Tanaka) |
| [Quadratic Formula Calculator](/math/quadratic-formula-calculator/) | a, b and c | Roots |
| [BMI Calculator](/health/bmi-calculator/) | units, weight and height | Your BMI |
Assumptions and limitations
- Individual maximums vary by ±10 bpm
- Not a diagnosis
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for age (used if no maximum is given) and resting heart rate (bpm) to confirm this.
Frequently asked questions
Why use Karvonen instead of a plain percentage?
Because it includes your resting rate, so zones shift as fitness improves.
What intensity should I pick?
Easy aerobic work is often 50 to 70%, harder sessions 80 to 90%.
Does it work with a measured maximum?
Yes, enter it and the age is ignored.
What does the Karvonen Formula Calculator calculate?
Target heart rate from heart-rate reserve and training intensity. It returns Target heart rate, Heart rate reserve and Maximum heart rate.
What formula does the Karvonen Formula Calculator use?
target = (HRmax − HRrest) × intensity + HRrest; HRmax = 208 − 0.7 × age when not given. The heart-rate-reserve method; the age-based maximum uses the Tanaka equation.
What do I need to enter in the karvonen Formula Calculator?
You enter Resting heart rate (bpm) and Intensity (%). Optional: Age (used if no maximum is given) and Maximum heart rate (bpm).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Individual maximums vary by ±10 bpm.
What are the limits of this calculator?
Individual maximums vary by ±10 bpm. Not a diagnosis.
What is an example of a karvonen Formula result?
With resting heart rate (bpm) 60, intensity 75 and age (used if no maximum is given) 40, the target heart rate is 150.
Where does the method come from?
The method follows: Karvonen MJ et al., Ann Med Exp Biol Fenn 1957;35:307; Tanaka H et al., J Am Coll Cardiol 2001;37:153.
Can I rely on this calculator for a decision?
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health. For this calculator in particular: Individual maximums vary by ±10 bpm.
Related calculators
- Max Heart Rate Calculator — Maximum heart rate and Karvonen training zones.
- Quadratic Formula Calculator — Solve ax² + bx + c = 0, including complex roots.
- BMI Calculator — Find your Body Mass Index (BMI) and weight status.
- Calorie Calculator — Daily calories to maintain, lose or gain weight.
Sources
- Karvonen MJ et al., Ann Med Exp Biol Fenn 1957;35:307; Tanaka H et al., J Am Coll Cardiol 2001;37:153
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.