Macronutrient Calculator

Enter Your Details to Calculate Macros

 

Getting started is easy – all you need to do is input a few key metrics into our macro calculator. These include your age, gender, weight, height, activity level, and current fitness goal. Why are these important? Because each factor significantly affects your Total Daily Energy Expenditure (TDEE), which is the number of calories your body needs to function and perform daily activities.

 

At Smarter Fitness, we use the Mifflin-St Jeor Equation, one of the most accurate methods to calculate BMR (Basal Metabolic Rate), then multiply it by your activity level to estimate your TDEE. From there, your target macros are calculated based on whether you’re looking to burn fat, build muscle, or maintain. It’s precise, personalised, and way more effective than any one-size-fits-all approach.

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Your Gender, Age, Weight & Height

 

These fundamental factors heavily influence how your body processes energy. For example, men and women naturally have different body compositions and hormone levels, which affect how they burn calories. Age also impacts your metabolism – it typically slows down as you get older. By including your exact weight and height, we ensure the calculator outputs accurate macronutrient targets suited to your unique physiology.

 

Smarter Fitness' calculator translates all these stats into an easy-to-understand calorie and macro split – giving you confidence in what you should eat each day.

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Select Your Activity Level & Goal

 

Your physical activity is a major determinant of how much fuel your body needs. Someone training five times a week needs more energy and more macros than someone with a sedentary desk job. The Smarter Fitness macro calculator allows you to choose from a range of activity levels, from sedentary to very active, ensuring your TDEE and macronutrients are

calculated accurately.

 

Next, you choose your goal: weight loss, muscle gain, or maintenance. Based on this, we tweak your calorie intake and macro ratios, allowing your body to shift into the optimal state for your goal.

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How We Calculate Your TDEE & Macros

 

Once we know your BMR and activity level, we calculate your Total Daily Energy Expenditure. This is the total number of calories you burn each day, even without exercise. If your goal is to lose weight, we apply a small calorie deficit; for muscle gain, a surplus. Then we assign the correct macro percentages – usually based on the 40/40/20 or 40/30/30 rule, depending on your needs.

 

Protein is calculated based on your lean body mass, fats are kept sufficient to support hormone function, and carbs are tailored to energy demands. The result? A perfectly balanced plan that works in real life.

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Backed by Evidence-Based Fitness Science

 

Our approach isn’t based on trends or guesswork. It’s backed by science and real-world application. We use only peer-reviewed formulas and nutrition principles used by sports nutritionists and certified fitness coaches across the UK and worldwide. That’s what sets Smarter Fitness apart our macro calculator is not only accurate but also trusted by thousands of active users every month.

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What Are Macros? Understanding the Basics

 

Macros – short for macronutrients – are the nutrients your body needs in large amounts to function properly. They include protein, carbohydrates, and fat. Each plays a specific role in the body and contributes a different amount of calories per gram:

• Protein = 4 kcal

• Carbohydrates = 4 kcal

• Fats = 9 kcal

 

While calories are important, macros determine the quality of those calories. Eating 2,000 calories from biscuits and fried food isn’t the same as eating 2,000 calories from lean meat, oats, and vegetables. That’s where macro tracking becomes far more powerful than simple calorie counting.

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Protein – The Building Block

 

Protein is critical for muscle repair, maintenance, and growth. It’s made up of amino acids, the “building blocks” your body uses to build tissue especially after a workout. Consuming the right amount of protein helps preserve lean mass when dieting and maximises muscle growth when bulking.

 

At Smarter Fitness, we typically recommend around 1.6 to 2.2g of protein per kg of body weight, depending on your goal. This ensures that whether you’re losing fat or gaining muscle, you’re protecting your strength and progress.

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Carbohydrates – The Energy Source

 

Carbs are your body’s preferred fuel source. They provide energy for training, recovery, brain function, and even hormone regulation. Despite their bad rep in some diet circles, carbohydrates are essential for anyone who wants to feel strong, fuel workouts, and avoid burnout.

 

We don’t just throw generic carb targets at you – the Smarter Fitness calculator adjusts your carb intake based on your training volume and intensity, ensuring the perfect balance between energy and fat loss.

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Fat – Essential for Hormones and Health

 

Fats play a vital role in maintaining hormonal balance, brain function, and vitamin absorption. Diets that are too low in fat can lead to fatigue, poor mood, and even hormonal issues. That’s why we ensure your macro plan includes enough healthy fats, typically around 20–30% of your daily intake.

 

Smarter Fitness encourages healthy sources like avocado, olive oil, nuts, seeds, and oily fish – foods that not only support fat intake but improve your overall diet quality.

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The Importance of Fibre and Micronutrients

 

While macros are vital, micronutrients (like vitamins and minerals) and fibre are just as crucial for gut health, immunity, and energy levels. Smarter Fitness always recommends a macro plan that includes whole, nutrient-dense foods, helping you naturally hit your vitamin, mineral, and fibre goals without needing piles of supplements.

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Difference Between Calories and Macros

 

Calories are the total energy in your food. Macros are where those calories come from. You could technically hit your calorie target eating just sugar and oil – but that wouldn’t fuel your body properly. That’s why macro-based eating is smarter. It keeps your calorie intake aligned with your goals, but ensures every calorie is purposeful and nutrient-rich.

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Why Track Macros? Not Just Calories

 

Counting calories alone gives you part of the picture. But if you want to build lean muscle, lose fat sustainably, and perform better in the gym, you need to know where those calories come from. Tracking macros helps you build meals that balance energy, protein, carbs, and fats, which leads to more muscle retention, better fat loss, and greater satiety.

Our free macro calculator at Smarter Fitness teaches you the science of eating with intention, giving you long-term control over your body composition, instead of just blindly slashing calories.

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The Problem with Calorie-Only Diets

 

Calorie-focused plans don’t teach you how to eat. You may lose weight, but it’s often at the expense of muscle. You’ll feel hungry, weak, and more likely to rebound. Macro-based diets, however, preserve lean mass, boost strength, and support mood and metabolism.

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Benefits of Tracking Macros for Long-Term Success

 

Macro tracking creates awareness and flexibility. You learn what’s in your food, how to build balanced meals, and how to adjust your intake as your body changes. Most importantly, it’s adaptable. Travelling? Eating out? Flexible macro eating still works – and the Smarter Fitness method makes it simple.

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Macro Tracking vs. Intuitive Eating

 

Intuitive eating works for some, but not everyone. Especially if you're new to nutrition, tracking macros gives you the data to understand how your body responds to food. Later, you can transition to eating more intuitively once you’ve mastered your body’s needs.

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Customise Your Macros Based on Your Fitness Goal

 

Smarter Fitness doesn’t just give you one static macro plan. We help you adjust your targets depending on your training cycle and goals. Whether you want to cut, bulk, or maintain, the calculator and this guide show you exactly how to modify your macros.

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Macros for Weight Loss

 

When cutting, the goal is to preserve muscle while dropping fat. That means high protein, moderate carbs, and controlled fat. We recommend a small calorie deficit, typically 10–20% below TDEE. This helps maintain energy and prevents binge-eating cycles.

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Macros for Muscle Gain

 

For muscle gain, you'll need a slight caloric surplus – about 10–15% above maintenance. Protein remains high, carbs increase to fuel workouts, and fat stays moderate. This promotes muscle growth without excessive fat gain – something most lifters struggle with.

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Macros for Maintenance

 

Maintenance is all about balance and stability. You’ll keep your TDEE calories and enjoy macro flexibility depending on training volume. Perfect for those who want to stay lean while building strength or transitioning between bulking and cutting phases.

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Real Coaching Tips for Each Goal

 

Every body is different. That’s why Smarter Fitness Coaching offers custom macro adjustments based on real progress, not guesswork. If weight loss stalls, we tweak your plan. If you’re not gaining muscle, we increase your carbs. It’s that simple – and that effective.

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How Smarter Coaching Can Help You Hit Your Targets

 

Our certified coaches work with you to tweak your macros based on actual results. We go beyond the numbers – coaching includes meal planning, accountability, and goal setting. Smarter Fitness is more than a calculator – it’s your partner in progress.

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How to Use This Macro Calculator

 

Using our macro calculator is easy. Enter your details, hit calculate, and get your personalised results instantly. We even give you suggested meals and macro ranges to make implementation stress-free.

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Step-by-Step Instructions

1. Enter your age, gender, weight, height.

2. Choose your activity level (honestly).

3. Pick your goal – lose fat, build muscle, or maintain.

4. Click calculate.

 

Example Macro Plans for Men & Women

 

Smarter Fitness includes example macro plans to help you visualise meals. A 70kg woman might have 130g protein, 170g carbs, and 55g fat for fat loss. A 90kg man building muscle might need 180g protein, 300g carbs, and 85g fat.

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Factors That Influence Your Daily Macro Needs

Your macro requirements aren’t static. They evolve based on:

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• Your weight and body fat %

• Your training intensity

• Your goals

• Your recovery and sleep

• Your stress levels and hormonal health
   

Smarter Fitness helps you monitor and update your plan as needed.

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FAQs for Calculating Macros

Here are answers to your top macro questions, based on real client concerns.

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What’s the Best Macro Split for Weight Loss?

 

Most people do well with 40% protein, 30% carbs, 30% fat – but it depends on your training and preference.

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How Do I Calculate Macros for Bodybuilding?

Use a small surplus, keep protein at 2.2g/kg, and increase carbs post-training. Smarter Fitness coaches can help you fine-tune this.

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What Is the 40-40-20 Rule for Macros?

It means 40% of your calories come from protein, 40% from carbs, and 20% from fats, commonly used for fat loss.

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How Do I Calculate the Macros in My Food?

Use food tracking apps, nutrition labels, or weigh your food. Over time, you’ll learn to eyeball your portions.

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Should I Track My Macros?

Yes, especially at the start. It gives you structure and confidence in your nutrition.