Flexible Dieting Macro Calculator

This macro calculator is designed by flexible dieters for flexible dieters. Flexible dieting is sometimes called IIFYM (If It Fits Your Macros).

Use it to calculate your optimal macronutrient ratios based on your age, height, weight, gender, and activity level. Then use your results with flexible dieting or IIFYM and count macros to lose weight, maintain, or gain muscle.





Formula ?If you know your body fat %, Lean Mass formula may be more accurate.

Activity Level







Need help putting your results into action? See our Flexible Dieting Solution and reach your goals faster!

Lose, Maintain, or Gain?

This macro calculator gives you the ability to adjust your macros at 4 different goal settings.

  • Lose puts you in a 20% calorie deficit which promotes safe, steady weight loss.
  • Lose 10% puts you in a 10% calorie deficit and is intended for those with less than 10 pounds to lose and who also wish to build muscle at the same time.
  • Maintain allows you to eat at macro levels that will keep you at your current weight.
  • Gain puts you in a 20% calorie surplus and is designed for people who are wanting to build muscle fast in conjunction with a comprehensive weight training program. It can also be used by people who are underweight.

What Are My Macros?

The following formula is used:

  1. Protein ratio is set at .825 grams per pound of bodyweight.
  2. Fats are set at 25% of daily energy expenditure.
  3. Carbohydrate grams come from the remainder.

Daily energy expenditure is calculated from your age, gender, height, weight, and exercise output.

See the full guide to macro ratios here.

Which IIFYM Formula?

The default formula is fine for most people. However, there are some exceptions.

1. If you are very lean (low body fat percentage) the standard formula may not be accurate. Use the “Lean Body Mass” setting. This uses a formula that factors specific body fat percentage into the equation and since muscle tissue burns many more calories than fat tissue while even at rest, it will give you a higher TDEE. This is perfect for “athletic body types” that want to use IIFYM to gain more muscle mass.

2. If you are classified as obese and have a lot of weight to lose, the standard formula will not be accurate because the equation used, factors for an average body fat percentage. If you happen to be above average it will skew the results. Please see this article for more clarification on how to do flexible dieting if you are obese.

You can calculate your ideal body weight here.

Adjusting Protein

Setting protein to Low adjusts the ratio to .65 grams per pound of body weight. Higher will set to 1 gram / lb.

Higher protein levels may be helpful if you have a strength training component in your IIFYM exercise routine. There are many differing opinions about this.

Try starting at the Normal level. If however you do a lot of lifting (3 times a week or more), then set to the High level.

Counting Macros per Meals per Day

By default, the results show the amount of grams of macronutrient should be eaten each day. Click on meal numbers to split this into a “per meal” basis for counting macros.

See our Healthy 5 Day Flexible Dieting Meal Plan. It includes 3 meals and 2 snacks per day.


By default, the results are for maintaining weight with IIFYM. Select either lose or gain if you are trying to lose fat or gain muscle. These are good starting points, but since IIFYM is highly individualized, you may have to play around with your macros until you find your personal goal reaching sweet spot. You can then count macros until you reach your desired goal.

Activity Level

A higher level activity means a higher daily calorie goal (TDEE). For example; if you can maintain your weight at 2,000 calories per day, then adding vigorous daily exercise to this means you need more calories to maintain your weight.

The same rule applies even if your flexible dieting goal is to lose weight.

If you are sedentary and your goal is to lose weight, your calorie goal might be (for example) 1,600 calories per day. If you decide to start exercising, the calculator will increase your daily calorie goal (say, to 1,800 calories/day). Although it may seem counter-intuitive, more energy is required to fuel your workouts, and your metabolism is increased – therefore calories should be higher.

Many people struggle with which exercise level to choose. Basically each level breaks down as follows:

  • Sedentary: Just normal everyday activity like a little walking, a couple flights of stairs, eating etc.
  • Light activity: Any activity that burns an additional 200-400 calories for females or 250-500 calories for a males more than your sedentary amount.
  • Moderate activity: Any activity that burns an additional 400-650 calories for females or 500-800 calories for males more than your sedentary amount.
  • Very Active: Any activity that burns more than about 650 calories for females or more than 800 calories for males in addition to your sedentary amount.

This varies based on your individual stats, but you can get a more specific amount of calorie burn by simply subtracting your sedentary calorie amount from the chosen exercise level amount.

You also need to determine how many calories you are burning: For this use an exercise database or a good app like MapMyFitness or a device like FitBit.

Too much physical activity combined with low calories could lead to muscle catabolism (breakdown of muscle fiber). This is not a good thing, and can actually stall your weight loss, so eat up!

If you need some inspiration, check out these incredible transformation stories of from people who used counting macros to reach their goals and get started with flexible dieting or IIFYM today.

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  • Mifflin, M. D., St Jeor, S. T., Hill, L. A., Scott, B. J., Daugherty, S. A., & Koh, Y. O. (1990). A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition, 51 (2), 241-247. Link
  • McArdle, W. D., Katch, F. I., & Katch, V. L. (2010). Exercise physiology: nutrition, energy, and human performance. Lippincott Williams & Wilkins. Link
  • Lemon, P. W., Tarnopolsky, M. A., MacDougall, J. D., & Atkinson, S. A. (1992). Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. Journal of Applied Physiology, 73(2), 767-775. study abstract link


  1. Sherry 5 days ago

    I did the macro calculater for moderate activity … i do two HiTT classes a week , one spin class plus a weight class .. on those work out days should I increase my macros ?
    Also do I have high days / refeed days ??

    • Ted Kallmyer 4 days ago

      Hi Sherry, you already set the calculator to Moderate activity which already accounts for the exercise you described. I’m not sure what your goals are but looking at the exercise you’ve described refeed days wouldn’t be necessary.

      • Sherry 4 days ago

        Thank you for your responds . I started flexible dieting about a year ago and love love love it !!! I lost 18 inches and 15 pounds in that time . I’m leaving for my winter holiday in feb for a couple of months and would love to lose another 8-10 pounds , and of course tone some more .
        I so know that if you don’t eat enough while working out you can in turn gain weight . It’s all about balance .!
        Flexible dieting lets me eat healthy plus I still get to eat some of the same foods I like .

        • Ted Kallmyer 4 days ago

          Great to hear and awesome job! It can be productive to have at least a day or 2 a month where you take a break and eat more than you normally would. It can keep the body from getting too comfortable with the same macros day in and day out. I personally vary my macros based on how active I am on a particular day and use sedentary on days I do no exercise.

  2. Emily 1 week ago

    Hello! I want to get off Keto but I’m afraid of gaining all the weight back. I don’t plan on eating unhealthy and want to have a well balanced diet that I can maintain for the rest of my life. The macro calculator suggests 25% fat , 40 % carbs, and 35% protein. Do you think I should follow these macros ? I’m scared that my 6 months of progress will go to waste.

    • Ted Kallmyer 1 week ago

      Hi Emily, It will be mostly about how many calories you are consuming. Why don’t you start with Lose 10 which will put you in a 10% deficit. See how your body responds and then move to your maintenance macros if everything looks good.

  3. Ashley 4 weeks ago

    Hi Ted!

    I was wondering if you were familiar with the Beachbody programs…I recently subscribed and love the variety I found. Starting today I committed to cleaning up the diet a little bit more (minus the 72% dark chocolate and Peanut Butter) BUT I also committed to the 21 Day Fix program, but instead of just doing that program I decided to add in another cardio video like the Country Heat or the Rockin’ Body dance videos to round out my hour long morning workout. What is the best way to estimate calorie burn in order to determine macros? Thanks!

    • Ashley 4 weeks ago

      I also tend to be a fairly active person in general, although I just started law school so it’ll be more like the life of a desk job except I take the stairs ALWAYS and i’ll go for short 5-10 minute walks every so often. I also eat a fairly healthy diet already but there are some things i’d like to clean up and focus on. The last time I was on the scale about 3 weeks ago I was 111 at a doctors appointment for a stress fracture, but I don’t know how much I weigh now, is it safer to err on the side of caution and input 115?

      • Ted Kallmyer 4 weeks ago

        Hi Ashley, I would start with moderately active and then adjust from there if you are losing too rapidly or not gaining etc. Not sure what your goals are.

        • Ashley 4 weeks ago

          I am trying to tone up/build muscle and lean out…I suppose you could consider me in the “skinny fat” phase of the process.

  4. Nataly Valenzuela 2 months ago

    How does carb cycling work with macro counting? Meaning if I go to the macro calculator and figure out my macros, how do I then adjust them for high carb and low carb days?? Thanks so much!

  5. Ralph 2 months ago

    Hi I’m 17 year old male 165lbs pretty muscular but need to loose some belly fat to show my abs what would you reccomemd me doing I train 6 times a week thanks

    • Ralph 2 months ago

      Trying to really shred myself basically just

    • Ted 2 months ago

      Hi Ralph, You’ll need to be in a calorie deficit to lose fat, but you don’t want to sacrifice all the hard work you’ve put in building the muscle. You should start with the “lose 10” setting when using the calculator. Also chose the high protein setting. That should get you started in the right direction.

  6. Raf 2 months ago

    I’m a female and I’m currently 17 years old. I am about 5’3″ and weigh 108 pounds. Although that is slightly underweight for my height, I am not happy with the way I look. I used to lift 4-5 times a week and was fit and toned with a lower body weight (100-103 lbs) and I was satisfied with how I looked but I wanted to gain more muscle mass. Instead, I wasn’t able to maintain my weight and I stopped going to the gym and ate unhealthy. Now I’m currently 108 pounds and I’ve gained extra fat on my cheeks and overall face, my arms became flabbier, my abs are not toned anymore and I gained thigh fat. My goal is to gain more muscle mass and start weight lifting, but I also desperately want to lose my face fat, arm fat and stomach fat as well. Do you know how many cals I should be eating and whether I should lose the weight first and then start lifting or can I do it at the same time? I want to start going back to the gym but I don’t know what I should be focusing on. I work in a camp so I would say that I’m lightly active during the day. Should I be calculate my macros with a lose 10%? It calculates 1541 calories with a normal protein intake of 89 grams, 200g carbs, and 43 grams of fat. Does that seem correct for my goals?

    • Ted 2 months ago

      Hi Raf, I think lose 10 is a good place for you to start and when you start weight training again use the high protein setting. Also, make sure you factor in your weight lifting exercise as well. On days you lift weights you’d most likely be moderately active.