The American Cancer Society and the American Heart Association both have these types of calculators on their websites. Fitness websites also have this type of information available.
Use the Target Heart Rate Calculator on this website http://www.cardiogod.com/tachycardia.html
I think what you are looking for is a heart rate MONITOR. You calculate what your target heart rate should be using a formula then the monitor helps you keep track of your heart rate.
Mayoclinic.com offers a heart rate calculator at the following link - http://www.mayoclinic.com/health/target-heart-rate/SM00083. It is important to use the heart rate calculator to ensure appropriate workouts.
Your target heart rate should be between 75-85% of your max heart rate. To find your max heart rate you take 220 and subtract your age from it to get your max heart rate. Then you can find your target heart rate easily by taking a calculator, typing in your max heart rate, and then type in "subtract (-) 15%". Record that number on a piece of paper of some sort. Then retype your max heart rate and then type in "subtract(-) 25%". Also record that number down on the same piece of paper you wrote the original number on and put a dash (-) between the numbers. This will show you the two numbers your target heart rate should be in-between.
You can find out information on what your target heart rate should be by going to your physician for a physical. Many health sites such as Mayo Clinic also provide plenty of information on your target heart rate.
To find target heart rates and the beneifits recieved from it try the following sites...www.livestrong.com/heart-rate-zone/ or www.briancalkins.com/HeartRate.htm
There is a heart rate calculator online at the fitness world site. You can test your own results and see them displayed on a chart that is ready to print for your convenience. The site is free to use.
If your heart gets stronger:Your resting heart rate will go downYour target heart rate for exercise will go upIt will be harder to raise your heart rate to the target heart rate
You can easily find your Target Heart Rate (thr) with this simple method. Subtract your age from 220 (226 for women) to calculate your Maximum Heart Rate (mhr). Find your training zone below and multiply that number times your maximum rate. im not sure if this is right but here you go.
Target heartrates will vary based on age and other factors. To find out what your particular heartrate target range should be go to http://www.mayoclinic.com/health/target-heart-rate/SM00083.
This website (http://www.heart.com/heart-rate-chart.html) has some very concise and useful charts for deciding your target heart rate, as well as instructions on how to use them. The Fitness Target Zones chart should be the most useful.
Your fat burning zone is also called your target heart rate. To find this, there is a certain formula you must follow. This website http://exercise.about.com/od/cardioworkouts/ss/findtargetheart.htm will help you find your target heart rate.