Nutrition Macros Calculator for website

I'm a personal fitness trainer and I have a Daily Caloric Intake javascript calculator on my website that allows a user to input his: weight, age, gender, height, and activity level ( from a drop-down list of choices) and it calculates his base daily calorie requirements, and depending upon which activity level he selects it recommends a specified calorie level. This part already works well. I would like to take that specified calorie recommendation and provide a few more recommendations for my web users. 1.) I would like to provide the users with the number of calories per day necessary to lose weight each week in increments of: -.5 lbs, -1 lb, -1.5 lbs, or -2 lbs per week. It's a basic math equation of expending 3500 calories each day over a 1 week period in order to lose 1 lb. So -3500/7 = -500 therefore ; -500 calories per day are required in order to lose 1 lb per week. So, If my original calculator had provided a specified calorie recommendation of 2000 calories per day based on the information the user provided, the new "1 lb of weight-loss per week" option would inform the user that their recommended calories per day would be reduced to 1500 in order to reach that goal. There are many websites that do this, so examples are prevalent online. 2.) I'd then like to take the number of calories recommended for weight-loss, for instance 1500 in the example above, and calculate the percentages of those calories that should be allocated to the 3 macro nutrient categories of: Carbohydrates, Proteins and Fats based on the desired percentages the user provides. For example; after the calculator states that 1500 calories per day is recommended to lose one pound per week for a user who's normal daily calorie requirement is 2000 calories per day, the user could input the following percentages into a calculator that calculates the number of calories that should be allocated to each group based on the percentage the user provides. Given the example above, if a user inputs 50% for Carbs - this would output a result of 750 calories based on a 1500 total calorie per day allotment. 25% Protein would = 375 calories, and 25% Fat would = 375 calories as well. 3.) Lastly, in addition to the calorie percentage breakdowns for the macros listed above, I would also like the calculator to list the # of grams associated with each percentage. That is also basic math as the number of grams of protein simply equals the number of calories divided by 4. In the above example 750 calories / 4 = 187.5 g protein. The calculation for Carbs is also divided by 4, so 375 calories / 4 = 93.75 g Carbs. And lastly the calculation for fat grams = the calories divided by 9. Therefore 375/9 = 41.67 g Fat 4.) [login to view URL] - Here is the current calculator on my webpage. 5.) Here is a similar version of a macro calculator - [login to view URL] Please submit a bid for costs and time to complete