American/European
In addition to the actual logging of foods and keeping track of all your days, iWatchr also has a food value calculator. This calculator can be set up to work with the American version formula or European version formula. 
To use the calculator, simply select the "Calculator" tab at the top of the screen. When the screen appears the calculator is set to the American formula. If you want to use the European formula just select that option at the top of the screen. For the American calculator enter the calories, fat and fiber of the food item into their respective fields. Use the serving field if you are calculating for more than one serving of this food and hit "Done" on the keyboard. iWatchr will then perform the calculation for you. Your calculation will also be temporarily saved in case you need to reference it when entering a new food into your log or into favorites (if you don't use Quick-Calc). If need be, use the calculator, then when entering a new food if you go back to the calculator to remember what the total score was, your total will still be there!! The last calculation stays there until a new one is done or the iWatchr application is closed.**Remember tho....using Quick-Calc is probably easier!!**
If you have changed the calculator to the European version, your calculator screen will look like the picture to the left... "Euro-Watchr". The same thing applies to the European calculator as did the American on how to use it.
Enter the values in the corresponding fields and hit "Done" on the keyboard to perform the calculation.There is one thing unique with the European calculator and that is how many fields can have values entered into them. If you look at the image to the left, you will see that it asks you for either "Calories" OR "Kilojoules"...NOT BOTH. The European formula uses either Calories with Saturated Fat or Kilojoules with Saturated Fat so therefore you have the choice on which one to use.
If you want to use Calories, simply enter a value into Calories field and Saturated Fat field but leave the Kilojoules field blank. If you want to use Kilojoules enter a value into the Kilojoules field and Saturated Fat field but leave the Calories field blank. If you accidently enter a value into both Calories and Kilojoules, iWatchr will notify you of the error. At that point just delete the value in one of those fields and you will be able to continue.
Activity
iWatchr also has a activity calculator for adding exercise into your daily logs. Theses values are deducted from your daily food total.
To use the Activity Calculator, enter your body weight, the amount of time you exercised and select which level 
of exercise you obtained. You can enter your body weight in pounds, kilograms or stones. By default the calculator is set up for you to enter pounds but a simple settings change will allow you to use kilograms or stones (See settings link for more info). Selecting the level of exercise will calculate the score as will the 'Done' button on the keyboard.
To determine which level of exercise you obtained, first figure out your Maximum Heart Rate (MHR). 220 - (your age) = MHR. Now, after you exercise, if your heart rate is 40% - 54% of your MHR, then you would select 'Light' as your level of exercise in the Calculator. If your heart rate is 55% - 69% of your MHR, then you would select 'Moderate'. If your heart rate is 70% or above then you would select 'Heavy' as your level of exercise.
Once you have calculated your obtained activity score, you can either manually add it to your day's log (as explained in "Logs") or you can have iWatchr do it for you. Hit the Menu button and then select "Send to Log". Select which day you want to add the calculated score to and iWatchr will add it to that day and subtract the amount from the day's total.
Custom Calculator
Want to tweak the formula a little bit for whatever reason? No problem! iWatchr also has the ability for you to enter in your own formula into the calculator and use that instead!!
For example....The European formula may vary from country to country in Europe so now you can make sure your calculations are being done correctly.
To use your own custom formula select the Calculator tab and then select the "Custom" option at the top. Hit the menu button and then "Configure". This will bring you to a screen where you can configure the calculator with your own formula. (You can also get to the configuration screen via Settings.)
Let's take the formula ((Calories / 50) + (Total Fat / 12) - (Fiber / 5)). If you have the formula itself in front of you and you compare it to the screenshot above then it's pretty self explanatory how it works. If you take basic Math rules, basically all equations can be broken up into sets of parenthesis to better show which mini equations are calculated first and whatnot, right?
Look at the formula I am using and look at the screenshot. The first line in the screenshot equates to the first set of parenthesis in the formula...(Calories / 50), the second line is the first "+", which is outside the parenthesis. The third line is the second set of parenthesis....(Total Fat / 12) and so on.
There is a fourth field for doing calculations as well. If your formula needs a fourth input option you could use it here as you did for the other ones. For any fields that you are not using leave them set up as show in the screenshot's fourth field ( X 1). Leaving the name of unused fields blank is not necessary. It's just a preference to clean up the finished look of the custom calculator. Then when performing calculations just leave the "0" in any unused fields (or blank) because 0 X 1 = 0.
