Protein Calculator — Free Online Daily Protein Intake Tool

How to Use the Protein Calculator

1. Select your unit system: Toggle between Metric (kilograms) and Imperial (pounds) at the top of the calculator. Your weight input and all results will use the selected unit.
2. Enter your body weight: Type your current body weight into the weight field. This is the primary variable in calculating protein needs, as recommendations are based on grams of protein per kilogram of body weight. For the most accurate result, use your morning weight before eating.
3. Select your activity level: Choose the option that best matches your regular physical activity. Sedentary means little to no exercise beyond daily living activities. Moderate covers 3-5 exercise sessions per week. Active indicates 6-7 days of exercise. Athlete is for competitive sports with intense training. Bodybuilder/Powerlifter is for those doing heavy resistance training focused on maximum muscle growth. Each level corresponds to a research-backed protein range in grams per kilogram.
4. Review your results: The results panel shows your recommended daily protein range in grams, your weight in kg, the protein-per-kilogram range for your activity level, and the calorie contribution from protein. Below, you will see per-meal protein targets for 3, 4, or 5 meals per day, followed by a list of top protein food sources with serving sizes and protein content. All values update instantly when you change inputs.

The calculator defaults to a 75 kg moderately active person. Replace these values with your own weight and activity level for a personalized recommendation.

Protein Calculation Formula and Method

This calculator uses weight-based protein recommendations established by sports nutrition research organizations including the International Society of Sports Nutrition (ISSN) and the American College of Sports Medicine (ACSM).

Activity Factor Ranges

• Sedentary (0.8 - 1.0 g/kg): The RDA minimum of 0.8 g/kg prevents protein deficiency. People with minimal physical activity do not require more, though slightly higher intake (1.0 g/kg) may support better body composition and satiety.
• Moderate (1.0 - 1.2 g/kg): For people who exercise 3-5 times per week at moderate intensity. This range supports recovery from regular exercise and helps maintain lean muscle mass during normal daily activities.
• Active (1.2 - 1.5 g/kg): For those exercising 6-7 days per week or performing physically demanding work. Higher protein supports the increased repair demands of frequent training and helps prevent overtraining-related muscle breakdown.
• Athlete (1.5 - 2.0 g/kg): For competitive athletes undergoing intense training. This range maximizes muscle protein synthesis and recovery. The ISSN recommends 1.4-2.0 g/kg for most athletes.
• Bodybuilder (2.0 - 2.5 g/kg): For individuals focused on maximum muscle hypertrophy through heavy resistance training. This is the upper evidence-based range beyond which additional protein provides minimal benefit for muscle building.

Step-by-Step Calculation Example

Consider a 70 kg person who exercises 4 times per week (moderate activity):

1. Body weight: 70 kg
2. Activity factor (moderate): 1.0 - 1.2 g/kg
3. Minimum protein: 70 x 1.0 = 70g per day
4. Maximum protein: 70 x 1.2 = 84g per day
5. Calories from protein (at midpoint 77g): 77 x 4 = 308 calories
6. Per-meal target (4 meals): 77 / 4 = ~19g per meal

This person should aim for 70 to 84 grams of protein daily. Spread across 4 meals, each meal should contain approximately 19 grams of protein. This could be met with just one chicken breast (31g) at lunch, one cup of Greek yogurt (17g) at breakfast, two eggs (12g) as a snack, and a serving of salmon (25g) at dinner — totaling about 85g.

Practical Examples

Example 1: Julia Plans a High-Protein Weight Loss Diet

Julia is a 34-year-old woman who weighs 68 kg (150 lbs). She does strength training 3 times per week and cardio twice (moderate activity). She wants to know her protein needs for preserving muscle while losing fat:

• Weight: 68 kg | Activity: Moderate (1.0-1.2 g/kg)
• Protein range: 68-82g per day
• Julia targets the higher end (82g) to maximize muscle preservation during her calorie deficit
• She distributes across 4 meals: ~21g protein per meal

Julia plans her meals: morning oatmeal with whey protein (25g), chicken salad at lunch (35g), afternoon cottage cheese snack (14g), and fish with vegetables at dinner (25g). She finds this achievable without supplements beyond one whey protein scoop. She also uses the macro calculator to balance her remaining calories between carbs and fat.

Example 2: Kevin Optimizes Protein for Bodybuilding

Kevin is a 27-year-old man who weighs 90 kg (198 lbs). He trains with heavy weights 6 days per week and is in a muscle-building phase (bodybuilder activity level):

• Weight: 90 kg | Activity: Bodybuilder (2.0-2.5 g/kg)
• Protein range: 180-225g per day
• Kevin targets 200g, the midpoint of his range
• He distributes across 5 meals: ~40g protein per meal

Kevin structures his meals around high-protein anchors: egg white omelet with cheese (40g), a chicken and rice bowl (45g), a post-workout shake with whey protein and milk (35g), grilled steak with sweet potato (40g), and a before-bed casein shake with peanut butter (35g). Hitting 200g requires deliberate planning but is achievable through consistent meal prep. He rotates protein sources weekly to maintain variety and ensure a broad amino acid profile.

Example 3: Linda Adapts Protein Intake at 65

Linda is a 65-year-old woman who weighs 60 kg (132 lbs). She does water aerobics twice a week and walks daily (moderate activity). Her doctor has emphasized the importance of adequate protein to prevent age-related muscle loss:

• Weight: 60 kg | Activity: Moderate (1.0-1.2 g/kg)
• Protein range: 60-72g per day
• Research recommends older adults aim for 1.0-1.2 g/kg minimum
• Linda targets 72g across 3 meals: ~24g per meal

Linda ensures each meal contains at least 24g of protein, which research shows is the minimum needed to stimulate muscle protein synthesis in older adults (compared to 20g in younger adults). She adds protein-rich snacks like a handful of almonds (6g) or a hard-boiled egg (6g) between meals. Her doctor notes that combining adequate protein with her water aerobics is the most effective strategy against sarcopenia. She also asks about the BMR calculator to understand her changing calorie needs as she ages.

Protein Sources Reference Table

Values are approximate and may vary by brand. USDA FoodData Central used as reference.

Tips and Complete Guide to Protein Intake

The Role of Protein in Your Body

Protein is not just for muscles. Every cell in your body contains protein. It forms the structural basis of hair, skin, nails, tendons, and ligaments. Enzymes that catalyze biochemical reactions, antibodies that fight infections, and hormones like insulin that regulate metabolism are all proteins. Your body contains over 10,000 different types of protein, and it continuously breaks down and rebuilds them. Unlike carbohydrates and fat, your body does not store protein in reserve. This means you need a consistent daily supply from food to maintain optimal function. When dietary protein is insufficient, your body breaks down muscle tissue to meet its needs — which is why adequate intake is essential regardless of your fitness goals.

Protein Distribution Throughout the Day

Research consistently shows that distributing protein evenly across meals is more effective for muscle maintenance and growth than consuming most protein in a single meal. The concept of the "muscle full effect" suggests that muscle protein synthesis is maximally stimulated by 20 to 40 grams of protein per meal, with amounts above this providing diminishing returns for muscle building (though excess protein still provides calories and amino acids for other uses). A practical approach is to divide your daily protein target by the number of meals you eat. For someone targeting 120g protein across 4 meals, each meal should contain approximately 30g of high-quality protein. If you tend to eat a low-protein breakfast, consider adding eggs, Greek yogurt, or a protein shake to balance your distribution.

Protein for Vegetarians and Vegans

Meeting protein needs on a plant-based diet is entirely possible but requires more deliberate planning. Aim for the higher end of your activity-based protein range to compensate for the lower digestibility of plant proteins (70-90% vs. 90-99% for animal proteins). Key strategies include: combining legumes with grains (rice and beans, lentil soup with bread) to form complete amino acid profiles; incorporating soy products (tofu, tempeh, edamame) which are complete proteins; using seitan (75g protein per 100g) as a meat substitute; adding seeds (hemp seeds: 10g per 3 tbsp, pumpkin seeds: 9g per oz) to meals; and considering plant-based protein powders (pea, rice, or hemp protein blends). Fortified plant milks, nutritional yeast, and spirulina can supplement your intake. Track your protein for a few weeks when transitioning to ensure adequacy.

Signs You May Not Be Getting Enough Protein

Inadequate protein intake manifests through several symptoms. Persistent fatigue and weakness, especially during physical activity, may indicate your muscles lack the amino acids needed for recovery. Slow wound healing suggests insufficient building blocks for tissue repair. Frequent illness can signal compromised immune function, as antibodies are proteins. Hair thinning or loss, brittle nails, and dry flaky skin indicate structural protein deficiency. Increased hunger and cravings (especially for carbohydrates and sugar) often occur because protein provides the strongest satiety signal of all macronutrients. Loss of muscle mass despite regular exercise is perhaps the clearest sign. If you experience multiple symptoms, evaluate your protein intake and consider using this calculator to set appropriate targets.

Common Mistakes to Avoid

• Using total body weight when significantly overweight: If your body fat percentage is well above normal, using lean body mass (total weight minus fat weight) gives a more accurate protein target. A 120 kg person at 40% body fat has 72 kg lean mass — protein needs should be based on the lean mass rather than total weight to avoid unnecessarily high intake.
• Relying on a single protein source: Each protein source has a unique amino acid profile, and variety ensures you get all essential amino acids in adequate amounts. Rotating between different animal and plant proteins also provides diverse micronutrients — fish provides omega-3s, red meat provides iron and B12, beans provide fiber and folate.
• Consuming all protein at dinner: Many people eat low-protein breakfasts and lunches, then overcompensate at dinner. This pattern is suboptimal because the body can only use 25-40g of protein per meal for muscle building. The remainder is used for energy or other metabolic processes. Spreading intake evenly stimulates muscle protein synthesis multiple times throughout the day.
• Ignoring protein quality: The Digestible Indispensable Amino Acid Score (DIAAS) measures protein quality. High-quality sources (DIAAS >100) like milk, eggs, and chicken provide more usable protein per gram than lower-quality sources (DIAAS 50-80) like wheat and rice protein. When counting grams, account for quality by slightly increasing intake from lower-quality sources.
• Over-supplementing instead of eating whole foods: While protein powders are convenient, whole foods provide vitamins, minerals, fiber, and phytonutrients that supplements lack. Aim to get 75% or more of your protein from whole food sources, using supplements only when needed to fill gaps or for post-workout convenience.

Frequently Asked Questions