Protein Calculator: How Much Do You Need?

Protein Calculator

Find out how much protein you need each day to lose fat, maintain or build muscle. The target adjusts for how much you strength train, your age and your body size, and comes split per meal with examples of what that looks like on a plate.

By the FitStack team. Last updated October 18, 2026. Formulas and sources are listed on this page.

How your protein target is set

The calculator multiplies a grams-per-kilogram figure by your body weight. The figure depends on your goal and how often you strength train:

Training	Lose fat	Maintain	Build muscle
No strength training	1.2 g/kg (1-1.4)	0.9 g/kg (0.8-1)	1.2 g/kg (1-1.4)
Strength train 1-2 days a week	1.6 g/kg (1.4-1.8)	1.2 g/kg (1-1.4)	1.4 g/kg (1.2-1.6)
Strength train 3+ days a week	2.2 g/kg (1.8-2.6)	1.6 g/kg (1.4-2)	1.8 g/kg (1.6-2.2)

The RDA (0.8 g/kg) is a minimum to prevent deficiency in sedentary adults, not a target for people who train or diet.¹
Regular lifters: muscle gains level off at about 1.6 g/kg, with 2.2 g/kg covering nearly everyone.² The ISSN recommends 1.4 to 2.0 g/kg for most exercising people.³
Dieting: needs rise in a calorie deficit, especially for lean people, to limit muscle loss.⁴^,⁵
Over 65: the target never drops below 1.0 to 1.2 g/kg, following the PROT-AGE recommendations.⁶
BMI 30 or above: the calculation uses adjusted body weight (weight at BMI 25 plus 40% of the excess), because protein needs follow lean mass rather than total weight.⁸

Protein per meal

Muscle-building dose per meal ≈ 0.4 g × body weight (kg), over at least 4 meals

Schoenfeld and Aragon's review suggests about 0.4 g/kg per meal across four or more meals to make the most of daily protein for muscle building.⁷ Your daily total is the priority; the per-meal figure is how to spread it.

Worked example

A 35-year-old, 82 kg (181 lb), lifting four days a week and trying to lose fat:

Target: 2.2 g/kg × 82 kg = 180 g a day (range 150 to 215 g) Four meals: 45 g each Muscle-building dose: 0.4 × 82 = 33 g per meal

What 30 g of protein looks like

Food	Amount for about 30 g protein
Chicken breast, roasted	95 g (3.4 oz)
Tuna, canned in water, drained	115 g (4 oz)
Salmon, cooked	135 g (4.8 oz)
Greek yogurt, plain nonfat	290 g (about 1 1/4 cups)
Cottage cheese, low fat	270 g (about 1 1/4 cups)
Eggs, large	5 eggs
Tofu, firm	175 g (6 oz)
Lentils, boiled	335 g (about 1 3/4 cups)

Values are approximate, from USDA FoodData Central.⁹ Look up more foods in the food nutrition database, or put your protein into a full plan with the macro calculator. If you take a GLP-1 medication, the GLP-1 protein calculator is built for eating with a smaller appetite.

Frequently asked questions

Can you eat too much protein?

For healthy adults, intakes up to about 2.5 to 3 g per kg a day have not shown harm in studies lasting months to a year. People with kidney disease are different: they are often advised to limit protein, so check with your doctor if that applies to you. The practical limit is usually that very high protein crowds out other foods you need.

Does protein timing matter?

Your daily total matters most. After that, spreading protein over three to five meals of roughly 0.4 g/kg each supports muscle building better than one or two large servings. Having a protein-rich meal within a few hours either side of training is sensible, but there is no narrow window.

Is plant protein as good as animal protein?

It can be. Most single plant proteins have less leucine and digest slightly less completely, so aim for the upper half of your range and combine sources such as soy, legumes, grains and seeds. Soy and blends of pea and rice protein perform close to whey in muscle-building studies when the dose is matched.

How much protein do older adults need?

More than younger adults. The PROT-AGE expert group recommends 1.0 to 1.2 g per kg a day for healthy people over 65, and more for those who are active or recovering from illness, because ageing muscle responds less to small doses. This calculator applies that minimum automatically.

How much protein do I need to build muscle?

About 1.6 g per kg of body weight a day captures most of the benefit for people who lift regularly, with up to 2.2 g/kg for those who want to cover individual variation. Without strength training, extra protein builds little muscle.