Rest 60 bpm, max 180 bpm. What is 70% by the Karvonen method?

144 bpm 60 + (180 − 60) × 0.7 = 60 + 84 = 144.

Why does Karvonen give higher numbers than percent of max at the same percentage?

It adds the resting heart rate back after scaling the reserve Scaling starts from rest, not from zero, so every value below 100% is higher.

What threshold did Karvonen identify for training improvements?

60% of the heart rate reserve The BCMJ article reports this threshold from his 1957 work.

Module 4: Training mathLesson 9 of 136 min read

Karvonen vs percent of max: two ways to set heart rate zones

A heart rate zone is a range of beats per minute tied to a percentage. The catch is the question of what that percentage is taken of. One method uses your maximum heart rate alone. The other, named after the Finnish physiologist Martti Karvonen, uses the distance between your resting and maximum rates. Both are simple arithmetic, but they give different answers for the same percentage. This guide works through both, step by step, with the numbers the calculator shows.

Method 1: percent of maximum

The simplest zone formula multiplies an estimated maximum heart rate by a percentage. If your maximum is 180 beats per minute, 70% of max is 0.7 × 180 = 126 bpm.

This needs only one number, which is why it is common. It ignores your resting heart rate. Two people with the same maximum get the same zones, even if one has a resting rate of 50 and the other 80. Percent of max also scales from zero, not from the resting rate, so low percentages can fall near or below a person's resting rate.

Percent of max

Target heart rate = max heart rate × percentage. Example: 180 × 0.70 = 126 bpm.

Method 2: heart rate reserve (Karvonen)

Heart rate reserve is the gap between your peak and resting heart rate. With a maximum of 180 and a resting rate of 60, the reserve is 120 beats.

Karvonen's method takes a share of that reserve and adds it on top of the resting rate. The BCMJ article on his work writes it as target HR = resting HR + (peak HR − resting HR) × K, where K is the chosen fraction.

The idea dates from a 1957 study by Karvonen, Kentala and Mustala on the effects of training on heart rate. In that work, Karvonen identified 60% of the heart rate reserve as the threshold at which training improvements were seen.

Heart rate reserve

Target heart rate = resting HR + (max HR − resting HR) × percentage.

The worked example

Take a 40-year-old with a resting heart rate of 60 bpm. At age 40, both common max formulas give 180 bpm: 220 − 40 = 180, and 208 − 0.7 × 40 = 180.

Rest 60, max 180, 70%

Reserve = 180 − 60 = 120. Share = 120 × 0.70 = 84. Target = 60 + 84 = 144 bpm. By percent of max, 70% is 0.70 × 180 = 126 bpm. The same 70% differs by 18 beats.

Why the two methods disagree

Percent of max scales everything from zero. Karvonen scales from your resting rate. Because the resting rate is added back, every Karvonen value sits above the matching percent-of-max value, except at 100%, where both equal the maximum.

In the example, 70% of reserve (144 bpm) lands exactly on 80% of max (0.8 × 180 = 144). So a zone label means little without knowing which method built it. A lower resting rate widens the reserve, which pushes the zones down; a higher resting rate pushes them up.

The table below shows the five zone edges the calculator uses, in 10% steps, for rest 60 and max 180.

50%: Karvonen 120 bpm, percent of max 90 bpm.
60%: Karvonen 132 bpm, percent of max 108 bpm.
70%: Karvonen 144 bpm, percent of max 126 bpm.
80%: Karvonen 156 bpm, percent of max 144 bpm.
90%: Karvonen 168 bpm, percent of max 162 bpm.
100%: both 180 bpm.

How accurate is it?

Both methods inherit the error in the maximum heart rate. Unless you have measured yours, it is an estimate from age. In Tanaka, Monahan and Seals (2001), individual values scattered around the age line with standard deviations of 7 to 11 bpm. A 10-beat error in the maximum moves every zone.

Karvonen also depends on a good resting rate. The BCMJ article notes that the formula can overestimate or underestimate exercise intensity in certain patients. It also cites Davis and Convertino, who found it a reasonably accurate method for estimating exercise intensity.

Medicines such as beta-blockers and heart conditions change heart rate, and these formulas are not made for that case.

What the calculator does

If you enter a ‘Resting heart rate’, the zones use heart rate reserve. Leave it empty and the zones use percent of max. The ‘Max heart rate’ menu picks the age formula, or choose I know mine and type it into ‘Your max heart rate’.

Enter your age and, if you know it, your resting heart rate to switch the zones from % of max to heart-rate reserve.

Heart rate zone calculator

Quick check

Three questions. Pick an answer to see why.

Rest 60 bpm, max 180 bpm. What is 70% by the Karvonen method?
Show the answer
Answer: 144 bpm 60 + (180 − 60) × 0.7 = 60 + 84 = 144.
Why does Karvonen give higher numbers than percent of max at the same percentage?
Show the answer
Answer: It adds the resting heart rate back after scaling the reserve Scaling starts from rest, not from zero, so every value below 100% is higher.
What threshold did Karvonen identify for training improvements?
Show the answer
Answer: 60% of the heart rate reserve The BCMJ article reports this threshold from his 1957 work.

Math, not advice

These guides explain published formulas and reference values. They are not medical advice, and the formulas aren't made for pregnancy, children or medical conditions. Each guide shows the date it was last checked.

Sources

Last checked October 27, 2026

Educational calculators based on published formulas. Not medical advice, diagnosis or treatment, and not made for pregnancy, children or medical conditions. Health disclaimer · Terms of use.