How To Calculate Your Heart Rate!

This new formula should apply to all healthy men and women between 18 to 81 years of age. The old formula has a 8 % difference than the new and improved one! Learn why!

When you're doing cardio to burn fat, you want to stay in the range of 65%-70% of your maximum heart rate. If the goal is to increase stamina and aerobic capacity, you aim for 85%. Piece of cake, everyone knows that. But how do you determine your maximum heart rate? For decades, the formula has been pretty simple: 220 minus your age = max heart rate.

However, there are some wrinkles to that formula when you consider guys like president Bush. At 55 years of age should have 220 - 55 = 165 as his maximum heart rate. Problem is, the guy is closer to a heart rate of 180 when doing his annual, widely published checkups. How can this be? And if Bush's real max heart rate is about 8% off from the standard formula, doesn't that mean that your so-called 70% or 85% could be equally skewed?

Harvard's Men's Health Watch published an explanation last year that sheds some new light on this matter. A couple of Colorado scientists did some exercise test reality checking and reviewed the results of 18,712 men and women of all ages. Based on the this real-life data they came up with a new formula:

    Maximum heart rate = 208 - (0.7 x age in years)

This should apply to all healthy men and women between 18 to 81 years of age. Now, president Bush is in exceptionally good health for his age and still exceeds his predicted maximum. Nonetheless, it appears the new formula is more accurate.

Simple Target Heart Rate Calculator
Using the 208 - (0.7 x age in years) formula.

Enter Your Age - Then press Calculate.
Heart Rate
Heart Rate per minute
(75% - 85% of Max)
Heart Rate
15 sec count

The Karvonnen formula is more advanced since it also takes into account your resting heart rate. This is your heart rate at complete rest. To determine this, take your pulse for 60 seconds just before you get out of bed... or take it for 30 seconds and multiply by 2.

Advanced Target Heart Rate Calculator
Using the Karvonen Formula.

  • For your age, use a whole year. (Between 0 and 100)
  • Put your Resting Heart Rate in the next box. (Between 30 and 100)
  • In the % box, use a number between 50 and 85. Do not include the %.
  • Click on the Calculate button, and it will calculate your target heart rate or that percentage.
Your Age in Years
Resting Heart Rate
% of Maximum Effort
Your Target Heart Rate

So, in practicality, what does this mean? The difference is the greatest for young and elderly people; people in the mid-forties will get the same numbers as with the old formula. However, if you're 20, your max heart rate is 194 instead of 200, meaning 70% of max = 136 instead of 140 and 85% of max = 165 instead of 170. That makes a difference when you're setting up the treadmill next time you're doing cardio. For a 65-year old, the max heart rate is 163 instead of 153, with 70% of max = 114 instead of 107 and 85% of max = 139 instead of 130.

Age Old Max New Max 70% 85%
20 200 194 136 165
25 195 191 134 162
30 190 187 131 159
35 185 184 129 156
40 180 180 129 156
45 175 177 124 150
50 170 173 121 147
55 165 170 119 145
60 160 166 116 141
65 155 163 114 139
70 150 159 111 135