Protein Calculator
Calculate how much protein you need per day in grams — based on body weight, goal, and training, using RDA and ISSN guidance. Free, no signup.
Decimal point or comma both work.
Aim for about 32 g of protein in each of your 4 meals.
≈ 406 g of cooked chicken breast (~31 g/100 g), or 21 large eggs (~6 g each), or 1260 g of plain Greek yogurt (~10 g/100 g) — mix and match across the day.
Where these protein numbers come from
The official U.S. Recommended Dietary Allowance for protein is 0.8 g per kg of body weight per day — but that's the amount needed to prevent deficiency in a sedentary adult, not the amount that supports training, recovery, or body-composition goals. Once you exercise regularly, the evidence points higher: the International Society of Sports Nutrition position stand (Jäger et al., 2017) recommends 1.4–2.0 g/kg for exercising individuals, with 1.6–2.2 g/kg widely cited for maximizing muscle growth and intakes up to ~2.4 g/kg during a calorie deficit to protect lean mass.
This calculator maps your goal and training frequency onto those published bands. It shows a range rather than one magic number because the research does too — individual responses vary, and anywhere inside your range is a good day. The mid-point "target" is simply the middle of your band: a practical number to aim at.
The per-meal split matters more than most people expect. Muscle protein synthesis responds meal by meal, and roughly 0.4 g/kg per sitting (about 25–40 g for most adults) is where the per-meal response starts to level off — so 130 g spread across four meals beats 130 g crammed into dinner. Three to five feedings a day is the pattern the ISSN recommends.
Hitting a protein target once is trivial; hitting it 5–6 days a week for months is what actually changes your body. That's a habit problem, not a knowledge problem — which is where a tracker helps. Set "hit my protein target" as a daily habit in HabitBox (free, no account, data stays on your phone, iOS and Android) and the streak does the nagging for you.
Note: this is a general estimate for healthy adults. Kidney disease, liver disease, pregnancy, and some medications change protein needs — talk to a clinician or registered dietitian for individual guidance.
Frequently asked questions
How much protein do I need per day?+
The U.S. RDA is 0.8 g per kg of body weight per day — the minimum to avoid deficiency in sedentary adults, not an optimum. If you train, the International Society of Sports Nutrition recommends 1.4–2.0 g/kg for exercising individuals, with 1.6–2.2 g/kg commonly cited for building muscle and up to 2.4 g/kg when dieting to preserve lean mass. For a 70 kg (154 lb) person building muscle, that's roughly 112–154 g per day.
Can my body only absorb 30 g of protein per meal?+
No — your body absorbs virtually all the protein you eat. The 30 g figure comes from studies on maximizing muscle protein synthesis per sitting: roughly 0.4 g/kg per meal (about 25–40 g for most people) appears to be where the per-meal anabolic response levels off. That's why spreading your total across 3–5 meals is a reasonable strategy, not because the rest is wasted.
Is a high-protein diet bad for my kidneys?+
For healthy people, no. Reviews cited in the ISSN position stand found no evidence that protein intakes in these ranges harm kidney function in people with healthy kidneys. If you have existing kidney disease, protein needs are different — follow your clinician's guidance, not a calculator.
Do I need more protein when losing weight?+
Counterintuitively, yes. In a calorie deficit your body is more likely to break down muscle for fuel, so higher protein (1.8–2.4 g/kg, paired with resistance training) helps you lose fat rather than muscle. Protein is also the most satiating macronutrient, which makes the deficit easier to stick to.
Does plant protein count the same as animal protein?+
Mostly. Plant proteins tend to be slightly lower in leucine and some essential amino acids, so if you eat fully plant-based, aiming for the upper end of your range and mixing sources (legumes + grains, soy, seitan) covers the gap. Total daily protein matters far more than any single source.
Make your protein target a daily habit
Knowing your number is the easy part — hitting it most days is what builds muscle. HabitBox lets you track 'hit protein target' as a one-tap daily habit, watch the streak grow, and stay consistent without a food-logging chore.
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