Protein Intake Calculator

How Much Protein Do You Actually Need?

The US and Canadian Dietary Reference Intakes set the Recommended Dietary Allowance (RDA) for protein at 0.8 grams per kilogram of body weight per day for a healthy, sedentary adult — a figure derived from an Estimated Average Requirement (EAR) of 0.66 g/kg, the amount needed to avoid a measurable nitrogen deficit in half of a study population, with a margin added on top to cover nearly everyone. Critically, the RDA is a minimum to prevent deficiency, not necessarily an optimal amount for building or maintaining muscle, supporting recovery from exercise, or preserving lean mass while losing weight — for those goals, sports-nutrition and clinical research both point meaningfully higher.

From RDA Minimum to Athletic Optimum: The g/kg Scale

The International Society of Sports Nutrition's position stand recommends 1.4 to 2.0 grams of protein per kilogram of body weight per day for most physically active individuals — roughly double to two-and-a-half times the RDA — as the range needed to support muscle protein synthesis and recovery from regular training. For people specifically trying to preserve lean muscle mass while eating in a calorie deficit to lose fat, more recent research supports intakes up to about 2.2 g/kg, since protein needs rise, not fall, when calories are restricted. This calculator uses five tiers along that scale, from the sedentary RDA baseline up to that higher weight-loss-preservation figure, rather than a single number for everyone.

Protein Needs for Older Adults

Aging is associated with anabolic resistance — older muscle responds less efficiently to a given amount of dietary protein than younger muscle does — which contributes to sarcopenia, the progressive loss of muscle mass and strength with age. The PROT-AGE Study Group, an international group of geriatric and nutrition researchers, recommends 1.0 to 1.2 g/kg/day for healthy adults over 65, rising to 1.2–1.5 g/kg/day for those managing an acute or chronic illness — well above the standard RDA. This calculator automatically raises your target to at least 1.0 g/kg if you're 65 or older and your selected activity level would otherwise fall below it.

Protein During Pregnancy and Breastfeeding

Protein needs rise measurably during pregnancy and lactation. The Institute of Medicine sets the RDA at 1.1 g/kg/day during pregnancy, reflecting both ordinary maintenance needs and the protein required for fetal, placental, and maternal tissue growth, and at 1.3 g/kg/day during breastfeeding, to support milk production. This calculator applies whichever is higher — your activity-based target or the relevant pregnancy or breastfeeding figure — so an active pregnant or breastfeeding woman's result never falls below the higher biological requirement.

Why Protein Timing and Distribution Matter

How your daily protein target is spread across the day affects how efficiently your body can use it. Research comparing even distribution against a skewed pattern — a small breakfast, moderate lunch, and large dinner, typical of many Western diets — has found that spreading protein evenly across three to four meals stimulates more muscle protein synthesis over the course of a day than concentrating most of it in one sitting, largely because each meal needs enough protein, roughly 25 to 40 grams for most adults, containing about 2.5 to 3 grams of the amino acid leucine, to maximally trigger the process. This calculator divides your daily target by four to suggest a straightforward per-meal amount.

Worked Example: Calculating a Real Daily Target

Consider a 28-year-old man who weighs 80 kg and trains regularly — strength or endurance exercise several times a week — selecting the 'Active / regular training' tier of 1.6 g/kg.

Step 1 — Baseline tier. His selected tier is 1.6 g/kg, and since he's under 65 and not pregnant or breastfeeding, no floor adjustment applies.

Step 2 — Total. 80 kg × 1.6 g/kg = 128 grams of protein a day.

Step 3 — Per meal. Dividing evenly across four meals: 128 ÷ 4 = 32 grams of protein per meal, comfortably within the roughly 25–40 gram range research associates with maximizing muscle protein synthesis at each sitting.