Free Health & Fitness Calculators – Calorie, BMI, Macro & More | BestCarbRecipes

Why Use Our Health Calculators?

All calculators use peer-reviewed formulas trusted by dietitians and fitness professionals worldwide.

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Accurate Formulas

Mifflin-St Jeor, Harris-Benedict & Katch-McArdle methods used by nutrition professionals.

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Instant Results

No loading, no waiting. Get your personalized numbers in seconds.

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All calculations happen in your browser. We never store your personal data.

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Works Everywhere

Fully optimized for mobile, tablet and desktop. Use anywhere, anytime.

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Calorie Calculator

Find your daily calorie intake for weight loss, maintenance or gain

Please fill in all fields with valid values.

Your Daily Calorie Targets

Our calorie calculator uses the Mifflin-St Jeor equation — the gold standard recommended by the Academy of Nutrition and Dietetics. Enter your details above for an accurate estimate of how many calories you should eat per day to reach your goal.

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BMI Calculator

Check your Body Mass Index and healthy weight range

Please enter valid height and weight values.

Your BMI Result
Underweight
<18.5Normal
18.5–24.9Overweight
25–29.9Obese
≥30

The BMI calculator is a quick screening tool used by healthcare professionals worldwide. While BMI doesn’t directly measure body fat, it’s a reliable indicator of weight-related health risk for most adults aged 20 and over.

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BMR Calculator

Calculate your Basal Metabolic Rate — calories burned at rest

Please fill in all fields with valid values.

Your Basal Metabolic Rate
calories/day

Your BMR is how many calories your body burns at complete rest. Multiply by your activity factor to get your Total Daily Energy Expenditure (TDEE).

Your BMR (Basal Metabolic Rate) represents the minimum calories your body needs to maintain basic functions like breathing and circulation. Understanding your BMR is the first step to building any effective nutrition plan.

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Macro Calculator

Get your protein, carbs and fat targets in grams per day

Please fill in all fields with valid values.

Your Daily Macro Targets
Total: calories/day

Our macro calculator distributes your daily calories into optimal protein, carbohydrate and fat targets based on your goal. Whether you’re cutting, bulking or eating at maintenance, hitting your macros consistently delivers results.

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Water Intake Calculator

Find out how much water you should drink each day

Please enter your weight.

Your Daily Water Target
Liters / day
Cups / day (8 oz)
Fl oz / day
Glasses (250ml)

Spread your intake evenly throughout the day. Increase by ~500ml on days you exercise and in hot weather.

Staying properly hydrated supports metabolism, digestion, skin health and cognitive function. Our water intake calculator accounts for your weight, activity level and climate to give you a precise daily hydration target.

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Protein Intake Calculator

Get your daily protein target based on weight and goal

Please enter your weight.

Your Daily Protein Target
Minimum (g)
Optimal (g)
g per kg body weight
Calories from protein

Protein is essential for muscle repair, immune function and satiety. Use our protein calculator to find your optimal daily protein range based on current research. Higher protein intakes during a calorie deficit help preserve lean muscle mass.

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Ideal Weight Calculator

Estimate your ideal body weight range using multiple formulas

Please enter your height (minimum 130 cm).

Your Ideal Weight Range

Different formulas produce slightly different results. Aim for the range that aligns with a BMI of 18.5–24.9 for your height. These are estimates — consult a healthcare provider for personalized guidance.

The ideal weight calculator uses four established formulas (Devine, Robinson, Miller and Hamwi) to estimate a healthy weight range for your height and sex. Most experts recommend targeting the midpoint of the range.

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Body Fat Calculator

Estimate body fat % using the US Navy circumference method

Please fill in all required measurements.

Your Estimated Body Fat
%

The body fat calculator uses the U.S. Navy body fat formula, which measures circumferences at key sites to estimate adipose tissue percentage. While not as precise as DEXA scanning, it’s a reliable, equipment-free method for tracking changes over time.

Frequently Asked Questions

Answers to the most common questions about calories, macros and healthy weight loss.

Most adults need between 1,600–2,400 calories per day depending on age, sex, height, weight and activity level. Women generally need 1,600–2,400 kcal and men 2,000–3,000 kcal. Use our free calorie calculator above for your personalized target based on the Mifflin-St Jeor formula.
The best calorie calculators use the Mifflin-St Jeor formula, which is considered the most accurate method for estimating resting metabolic rate. Our calorie calculator uses this formula and adjusts for your activity level and weight goal to give you targeted daily calorie recommendations.
BMI is a useful screening tool but has limitations. It does not directly measure body fat and can misclassify muscular individuals or athletes. For a complete picture of your health, combine BMI with waist-to-height ratio, body fat percentage and other health markers. Your doctor can help interpret results in context.
Macros (macronutrients) are the three nutrients that provide your body with energy: protein (4 kcal/g), carbohydrates (4 kcal/g) and fat (9 kcal/g). Tracking macros means hitting specific daily gram targets for each nutrient rather than just counting calories, allowing you to optimize body composition for your specific goal.
Research recommends 0.7–1g of protein per pound of bodyweight (1.6–2.2g per kg) for active individuals looking to build or maintain muscle. Sedentary adults need a minimum of 0.36g/lb (0.8g/kg). During a calorie deficit, higher protein intake (up to 1.2g/lb) helps preserve lean muscle mass while losing fat.
A calorie deficit occurs when you consume fewer calories than your body burns each day. A deficit of 500 calories per day typically results in approximately 0.5 kg (1 lb) of fat loss per week. Deficits greater than 1,000 calories per day are generally not recommended as they can lead to muscle loss, nutrient deficiencies and metabolic adaptation.
Safe, sustainable weight loss is typically 0.5–1 kg (1–2 lbs) per week. Achieve this through a moderate calorie deficit (300–500 kcal/day), regular physical activity, adequate protein intake to preserve muscle, and prioritizing whole foods, fiber and hydration. Avoid extreme diets — gradual changes are more sustainable long-term.

Your Complete Guide to Health & Fitness Calculators

Understanding your body’s energy needs is the foundation of any successful health journey. Whether your goal is weight loss, muscle gain or simply feeling your best, accurate data empowers smarter decisions.

What is the Mifflin-St Jeor Formula?

The Mifflin-St Jeor equation is the most accurate formula currently available for estimating resting metabolic rate (RMR). Developed in 1990, it calculates the number of calories your body needs at rest based on your sex, age, height and weight. Our calorie calculator and BMR calculator both use this formula.

  • Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
  • Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

How to Use the Calorie Calculator for Weight Loss

Enter your personal details, select your activity level and choose “Lose Weight” as your goal. The calculator will show you three calorie targets: a mild deficit (−250 kcal), a moderate deficit (−500 kcal) and a larger deficit (−750 kcal). Most people achieve the best results targeting a 500-calorie daily deficit, which equates to roughly 0.5 kg (1 lb) of fat loss per week.

Understanding Your Macro Ratios

For weight loss, we recommend a higher-protein split (30–35% protein, 35–40% carbs, 25–30% fat) to preserve muscle tissue while in a deficit. For muscle gain, slightly higher carbohydrates support training performance and recovery (25% protein, 45–50% carbs, 25–30% fat). Adjust these targets over time based on your results.

Low-Carb Diets and BestCarbRecipes

At BestCarbRecipes, we believe that understanding your carbohydrate intake is key to sustainable energy management. Many of our recipes are designed to hit optimal carb targets that align with the macro recommendations from our calculator. Browse our recipe collection to find meals that fit your daily numbers.

Combine these calculators with our nutrition guides and low-carb recipes for the best results.

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Low-Carb RecipesHundreds of healthy, macro-friendly meals
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Meal PlansWeekly plans matched to your calorie goals
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Nutrition GuidesLearn about macros, fiber and micronutrients
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High-Protein RecipesHit your protein targets deliciously
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Weight Loss TipsEvidence-based strategies that actually work
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Health BlogLatest research, tips and recipe ideas

Ready to Hit Your Goals?

Now that you know your numbers, put them into action with our macro-friendly, low-carb recipes designed to make healthy eating effortless.

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