Protein Calculator

Most protein calculators pull a number out of the air. Ours uses the ranges the research actually landed on:

• Build muscle: 1.6 to 2.2 g per kg of body weight (0.73 to 1.0 g per lb). A 2018 meta-analysis of 49 trials found that muscle gains from extra protein plateau at about 1.6 g/kg/day, with the upper end of the confidence interval near 2.2 (Morton et al., British Journal of Sports Medicine).
• Stay strong: 1.4 to 1.8 g/kg. The International Society of Sports Nutrition position stand on protein and exercise puts most exercising adults at 1.4 to 2.0 g/kg/day.
• Endurance: 1.6 to 2.0 g/kg. Two studies measured the need directly after a 20 km run: the average need came out at about 1.6 g/kg, with a recommended intake of about 1.8 to 1.9 (Kato et al., 2016, PLOS ONE; Williamson et al., 2023, Medicine & Science in Sports & Exercise, which found no difference between women and men). A 2025 review lands on about 1.8 g/kg, and above 2.0 on low-carb training days and rest days (Witard et al., Sports Medicine).
• Lose fat, keep muscle: 2.3 to 3.1 g per kg of lean mass. A systematic review of dieting, resistance-trained athletes (Helms et al., 2014) landed on 2.3 to 3.1 g per kg of fat-free mass, scaled up with leanness and how hard the deficit is. In a 2016 McMaster trial (Longland et al., American Journal of Clinical Nutrition), men eating 2.4 g/kg in a 40% deficit with hard training gained 1.2 kg of lean mass while losing 4.8 kg of fat; the 1.2 g/kg group held lean mass flat. A 2025 meta-regression of 29 studies (Refalo, Trexler and Helms, Strength and Conditioning Journal) found more protein went with better lean-mass retention, and the link was strongest when protein was counted per kg of lean mass. And in a 2026 trial (Nait-Yahia et al., European Journal of Clinical Nutrition), 16 resistance-trained people on a 40% deficit for four weeks, eating 2.3 g/kg and lifting five days a week, lost fat with no change in lean mass.
• Waist tape estimate. The U.S. Army one-site tape test: body weight plus one waist measurement at the navel, checked against DXA scans in 1,904 soldiers (Taylor et al., 2024, Obesity Science & Practice). We use the equations as the Army fielded them (Army Directive 2023-11). Good for a starting point, rough for one person.
• Per meal: your daily target split across four meals. Schoenfeld and Aragon (2018, Journal of the International Society of Sports Nutrition) suggest at least 0.4 g/kg per meal across four meals. Spreading protein across the day beats loading it into one sitting.

The RDA of 0.8 g/kg is the floor for a sedentary adult, not a target for anyone who trains.

Want the full picture on food sources, timing and the common myths? Read our complete guide to protein.

Counterintuitive, but not a mistake. In a surplus, calories are plentiful and protein past about 1.6 g/kg buys you nothing extra. In a deficit, the body pulls back on muscle protein synthesis, and higher protein is the lever that keeps muscle on the frame while fat comes off. Training does most of the protecting; protein makes sure the raw material is there.

Honest caveat: not every study agrees you need the top of the range. A 2025 trial in college athletes on a moderate 25% deficit (Kanaan et al., European Journal of Clinical Nutrition) found 1.2, 1.6 and 2.2 g/kg all preserved lean mass equally over six weeks. The higher numbers matter most when you are already lean, the deficit is aggressive, or the diet runs long. That is why the calculator gives you a range and places you inside it based on how hard you are cutting, instead of pretending one number fits everyone. One more caveat: these ranges come mostly from studies on men, so treat the targets for women as less certain.

The full cutting playbook: How to Maintain Muscle While Cutting.

A calculator has to turn a research range into one number. These are the choices we made to do that. They are Die Tryin Co. choices, not findings from a study:

• Where you land in the range15%, 50% or 85% of the way up, set by how often you train or, for fat loss, by how hard you are cutting.
• Body fat is required for fat lossThe research on dieting lifters set protein by lean mass, so we do not guess it from body weight.
• A floor when cuttingThe fat-loss target never drops below 1.4 g per kg of body weight, so a high body fat reading cannot pull it too low.
• Rounding to 5 gNobody weighs protein to the gram.
• Four mealsThe per-meal number is your daily target split four ways: a practical target, not a max.

Not past the top of your range. In the trials behind these ranges, healthy trained adults showed no harm at these intakes, and the ISSN position stand notes that intakes above 3 g/kg have been studied in resistance-trained people. But protein above your range is just expensive calories that could have gone to carbs for training. If you have a kidney condition or any diagnosed illness, get your doctor's read before pushing intake up.

Two more rules we use ourselves: whole food first, powder second. And collagen does not count toward this number. Collagen Peptides are low in leucine and are not a complete protein; they have their own job (joints, tendons, connective tissue). Count whey, meat, fish, eggs, dairy, and complete plant proteins.