Protein Calculator
Find your daily protein requirement based on body weight, activity, and fitness goals.
Find your daily protein target based on body weight, activity level, and fitness goal.
Good Protein Sources
How Much Protein Do You Need Per Day?
How protein targets are calculated
Protein needs are expressed as grams per kilogram of body weight (g/kg). The minimum RDA of 0.8g/kg prevents deficiency in sedentary adults but is not optimal for active people. Targets increase with training volume because muscle protein breakdown is higher and repair demands are greater: endurance athletes typically need 1.2–1.4g/kg, and strength athletes 1.6–2.2g/kg. This calculator adjusts the target based on your selected activity level and goal.
Protein and muscle growth
Building muscle requires both a training stimulus and adequate amino acids, particularly leucine, which triggers muscle protein synthesis (MPS). Research suggests roughly 25–40g of a complete protein source per meal is needed to maximally stimulate MPS — amounts below this underdeliver, and amounts above produce diminishing returns in a single sitting. This is the primary reason distribution across the day matters alongside total intake. For your full macro split including carbohydrates and fats, try the macro calculator.
Protein during a calorie deficit
When eating below maintenance, protein needs increase — typically to 1.8–2.4g/kg — because the body is more likely to use amino acids for energy (gluconeogenesis) when calories are scarce. Higher intake during a deficit helps preserve lean muscle by providing a continuous supply of amino acids for tissue repair. This muscle-sparing effect is one of the strongest evidence-based reasons to prioritise protein when cutting. The BMR calculator shows your maintenance calorie needs at different activity levels.
Lean mass vs total body weight
Fat tissue has very low protein turnover and minimal protein requirements. Calculating from total weight can therefore overstate needs for people with higher body fat percentages. When you enter your body fat %, the calculator switches to lean body mass (total weight minus fat mass) and applies the same g/kg multipliers to the metabolically active tissue that actually needs the protein, producing a more accurate target.
Worked example
Male, 30 yrs, 80 kg, 180 cm, moderately active, goal: build muscle. Protein multiplier at this activity and goal = 2.0 g/kg. Target = 80 × 2.0 = 160 g/day. Split across 4 meals: 40 g per meal (e.g. 150 g chicken breast + 200 g Greek yoghurt each provides ~40 g combined). Range: minimum 144 g, maximum 192 g.
How to Reach Your Daily Protein Target
Best dietary sources
Complete proteins contain all nine essential amino acids the body cannot make itself. Animal sources — chicken, beef, fish, eggs, and dairy — are all complete. Plant sources are often incomplete individually but can be combined: rice and beans together provide a full amino acid profile. Protein density varies considerably: chicken breast ~31g per 100g, canned tuna ~25g, Greek yoghurt ~10g, cooked lentils ~9g, cooked quinoa ~4g.
Meal timing and distribution
Total daily intake is the primary driver of results, but spreading protein across 4–5 meals every 3–4 hours consistently outperforms concentrating most of it in one or two sittings. A protein-rich meal within 1–2 hours of resistance training is particularly valuable for recovery. Aiming for 25–40g per meal — achievable with a chicken breast, a tin of tuna, or a large serving of Greek yoghurt — supports continuous muscle protein synthesis throughout the day.
Protein and ageing
After age 50, the body becomes less efficient at converting dietary protein into muscle — a phenomenon called anabolic resistance. Older adults need a larger dose per meal (35–40g rather than 25g) to achieve the same muscle protein synthesis response. The standard RDA of 0.8g/kg significantly underestimates needs for those over 65; most current guidelines for older adults recommend a minimum of 1.2–1.6g/kg to slow age-related muscle loss (sarcopenia).
Can you eat too much protein?
For healthy adults, intakes up to 2.5g/kg per day are considered safe and well-tolerated. The concern about kidney damage from high protein intake applies specifically to people with pre-existing kidney disease — the evidence does not support this risk in healthy individuals. Intakes above ~2.2–2.4g/kg provide no additional muscle-building benefit for most people, even with heavy training, and may displace carbohydrates and fats needed for energy and recovery.
Complete vs incomplete proteins
A complete protein contains adequate amounts of all nine essential amino acids the body cannot produce itself. All animal proteins — meat, fish, eggs, dairy — are complete. Most plant proteins are incomplete: legumes tend to be low in methionine; grains tend to be low in lysine. Combining plant proteins across the day (rice with lentils, bread with peanut butter) provides a full amino acid profile; they do not need to be eaten in the same meal. Leucine — the key amino acid for triggering muscle protein synthesis — is notably lower in most plant foods than in animal proteins.
Plant-based protein — what to know
Plant-based diets can fully support muscle building and athletic performance, but require more attention. Because most plant proteins are less digestible and have lower amino acid scores than animal proteins, current research generally recommends plant-based eaters target 20–30% more total protein than the equivalent omnivore recommendation to compensate for reduced bioavailability. Soya (tofu, tempeh, edamame) and quinoa are the most complete plant proteins. Larger per-meal portions (35–45g rather than 25–30g) may also be needed to achieve the same anabolic stimulus, particularly for leucine.
Protein quality scores
Two scores rate protein quality. PDCAAS (Protein Digestibility Corrected Amino Acid Score) compares a food's amino acid profile to human requirements and adjusts for overall digestibility, with a maximum of 1.0. DIAAS (Digestible Indispensable Amino Acid Score), the newer standard, measures absorption specifically in the small intestine and gives more accurate per-food values. Egg, casein, and whey all score at or above 1.0. Most plant proteins score 0.5–0.8. At the higher intakes typical for active people, overall amino acid supply tends to compensate for lower individual food scores — quality matters most when intake is close to the minimum.
Frequently Asked Questions
How much protein do I need per day?
Sedentary adults need around 0.8g per kg of body weight to prevent deficiency. Active people need more: endurance athletes typically 1.2–1.4g/kg, and strength athletes 1.6–2.2g/kg. When in a calorie deficit, 1.8–2.4g/kg helps preserve muscle mass. Enter your stats in the calculator above for a target tailored to your activity level and goal.
Why does the calculator use lean body mass?
Fat tissue has very low protein requirements — calculating from total weight can overstate needs for people with higher body fat. When you enter a body fat percentage, the calculator applies the g/kg multipliers to your lean body mass (total weight minus fat mass) instead, producing a more accurate target for the muscle and organ tissue that actually uses the protein.
Does it matter when I eat my protein?
Muscle protein synthesis is maximised by consuming 25–40g of protein per meal every 3–4 hours. Total daily intake is still the primary driver of results, but spreading protein evenly across 4–5 meals consistently produces better muscle-building outcomes than concentrating most of it in one or two large meals.
Is a high-protein diet safe?
For healthy adults, intakes up to 2.5g/kg per day are safe and well-tolerated. Concerns about kidney strain from high protein apply only to people with existing kidney disease and are not supported by research in healthy individuals. Going above ~2.2–2.4g/kg provides no additional muscle-building benefit for most people, even with heavy resistance training.
Evidence & Methodology
How This Page Is Grounded
Method
Multiplies body weight by the selected protein factor, using reference-intake and activity ranges explained on the page.
Important limitation: Needs vary with health, age, pregnancy and training; medical conditions can require professional advice.
Primary Sources
- Dietary reference values for protein European Food Safety Authority
- Physical activity guidelines UK Chief Medical Officers
Quality Checks
Unit conversion and each goal multiplier are checked with worked examples.
See how sources are selected and corrections are handled in our Editorial & Calculation Methodology, and which automated checks this page has to pass in How We Test.