The truth is, we’re all pretty different when it comes to our nutrition and what our bodies need to optimize results. Whether you are looking to lose fat, put on muscle mass, or recomp, there’s much more than one factor to consider. The best approach for you requires taking a look at your current fitness level, age, height, weight, gender, workout routine, past diet, genetics, and personal taste preferences.

The bottom line is that there is no one-size-fits-all approach. And what worked for your friend or your friend’s friend won’t always work for you. So, where do you go from here?

Here are five nutrition calculators designed by registered dietitians and backed by science to help you fine-tune your nutrition goals and get matched with the perfect meal plan.

Man on Scale



These tips will help you maintain your diet and keep you on the right path.

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Courtesy of Trifecta Nutrition

1. BMI Calculator

Your body mass index or BMI is a measurement of your current body size and predicted body fat, using a ratio of your weight to your height.

While your body mass index may not always feel like the most meaningful piece of information, outside of body fat analysis testing, it’s one of the few tools we have to determine whether or not you are overweight or underweight.

Why does this matter? Well, you might be thinking you need to lose weight, but in actuality you’re already at a healthy weight and just need to lose body fat or change your body composition through a better diet and workout regime.

Before deciding whether or not you should be changing your weight, a good starting place is learning where your current weight falls on the BMI scale.

Get your BMI in minutes using the free BMI calculator.


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Trifecta TDEE calculator on a smart phone


2. Calorie Calculator

Once you know your goal: weight loss, weight gain, or weight maintenance, the next step is determining exactly how many calories you need to eat a day to reach this goal.

Regardless of the type of food you eat, calorie control is the only proven method – we know of – that directly impacts weight maintenance.

If your main goal is to just see the number on the scale drop (or increase), you’ve got to get your calories dialed in.

Your calorie needs are determined using a combination of your current age, height, weight, gender, fitness level, activity level, and weight goal. And the more detailed the calculator gets with these factors, the more accurate your recommendations will be.

Learn your unique calorie needs with this free TDEE calculator


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3. Macro Calculator

Calories (aka how much you eat) determines how much weight you can gain or lose, but macronutrients (aka the balance of your calories) will determine the type of weight you carry. Meaning, if you want to drop body fat and maintain muscle mass (improve your body composition), getting your macro ratio in check is a great start.

Your macros are your calories organized into three nutrient groups: protein, fat, and carbs. The amount of protein you need depends on your goals and how much muscle mass you have. Your carb needs are most closely related to your activity level, and fat needs depend on overall calories and metabolic efficiency (aka how effectively your body can burn fat or carbohydrates for energy).

Macro needs can also vary depending on your body composition, age, health needs, lifestyle preference, and fitness requirements. To get your fully customized macro goals, check out this advanced macro calculator.


Following a keto diet? Check out this keto macro calculator for keto-specific goals.

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4. Water Calculator

Water is not only essential for survival but also plays a major role in numerous bodily functions including sleep, nutrient metabolism, and digestion.

Drinking more water is also associated with more weight loss because it is calorie-free and helps fill your stomach, calming your appetite. In most cases, when you aren’t drinking enough water, you’re getting fluids elsewhere – like sugary beverages and processed drinks that might not be helping you reach your goals in the long run.
 Additionally, water is critical for performance, keeping your body well hydrated to power through your workouts.

To learn your exact water needs, check out this water calculator that estimates your fluid goals based on your training schedule, fitness goals, and bodyweig

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5. Best Diet For You Calculator

One of the hardest questions for most people to answer when it comes to starting any new diet plan is, what type of diet is best for their goals?

As it turns out, the answer is a bit simpler than you’d think. Ultimately the best weight loss or muscle gain meal plan for you is the one with the types of foods you enjoy eating the most. In other words, if you don’t like what you are eating, there’s little chance you will stick with it. And change is the result of consistency and patience – it doesn’t happen overnight!

Outside of taste preferences, you can also fine-tune your approach based on general nutrition and fitness needs – ensuring you are feeding your body what it needs to thrive. Some macro approaches are better than others when it comes to losing fat or putting on mass, but remember calorie control still reigns supreme.

To help you stick to your plan, regardless of which diet type you choose, focus on the way your food is making you feel from the inside out and seriously ask yourself if this is something you can maintain for long periods of time.

Check out this meal plan quiz to get paired with the best diet for you.