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Protein Intake Calculator

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Enter your sex, age, height, weight and activity level to see a suggested daily protein target, your estimated BMR and maintenance calories, and how it compares to the RDA minimum for your sex.

Your details

Sex
years
This calculator is for adults aged 18 and over.
Before we calculate — do any of these apply?
If you tick any of these, the calculator will not set a protein target and will point you to tailored advice instead.
Suggested daily protein
120 g/day
Protein per kg body weight
1.6 g/kg/day
Reference minimum for your sex
56 g/day
Estimated BMR
1,718 kcal/day
Estimated maintenance calories
2,662 kcal/day
Share of maintenance calories
18% of maintenance calories

This is a population reference minimum, not a personalised target.

Estimate only.This calculator provides a general protein estimate, not a medical diet plan. Protein needs vary with age, body size, training, health and overall calorie intake. If you are pregnant, breastfeeding, under 18, have kidney disease or reduced kidney function, manage a health condition, follow a prescribed diet, take medication that may affect nutrition needs, or have a history of disordered eating, seek personalised advice from a qualified health professional.

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How to use this calculator

  1. Pick your sex — it sets the BMR formula constant and the RDA comparison point.
  2. Enter your age, then your height and weight, picking whichever units you prefer.
  3. Choose the activity level that best reflects your typical week.
  4. Read your suggested daily protein target, your estimated BMR and maintenance calories, and how your target compares to the RDA minimum for your sex.

Nothing is submitted anywhere. The calculation runs in the page as you type, and the link in your address bar carries your figures, so it can be shared or bookmarked.

What do I need to enter?

  • Sex — Male or Female. It sets the BMR formula and the reference minimum shown; it does not change the protein per kilogram.
  • Age — whole years, 1 to 120. Under 18 you are pointed to tailored advice instead of a target.
  • Height and Weight — in any unit offered. Height must be 130 to 220 cm (or the equivalent) and weight 30 to 300 kg. Weight sets the protein target.
  • Usual activity level — Sedentary, Lightly active, Moderately active, Very active or Extra active. It sets the grams per kilogram and the maintenance calories.
  • Before we calculate — four tick boxes (pregnant or breastfeeding, kidney disease, a health condition affecting nutrition, an eating disorder). Ticking any one withholds the target and shows advice instead.

What do the results show?

  • Suggested daily protein — the main figure, in grams per day.
  • Protein per kg body weight — the target divided by your weight in kilograms.
  • Reference minimum for your sex — 56 g/day for men and 46 g/day for women, a population minimum rather than a personal target.
  • Estimated BMR and estimated maintenance calories — daily energy at rest and with your activity level, in kcal.
  • Share of maintenance calories — the percentage of those calories your protein target supplies, at 4 kcal per gram.

How is protein intake calculated?

Protein target [g/day] = Weight [kg] × g per kg for your activity level
  • Sedentary — 0.8 g/kg (general adult RDA)
  • Lightly active — 1.2 g/kg
  • Moderately active — 1.6 g/kg
  • Very active — 1.8 g/kg
  • Extra active — 2.2 g/kg
  • BMR (Mifflin–St Jeor) and maintenance calories use sex, age, height and weight together.

Worked example. A 30-year-old, 178 cm, 75 kg man who is moderately active has a protein target of 75 × 1.6 = 120 g/day, which is 120 ÷ 75 = 1.6 g per kg of body weight per day. For context, the population reference minimum for men is 56 g/day. His estimated BMR is 1,718 kcal/day and his estimated maintenance calories are 2,662 kcal/day, so that protein target supplies about 18% of his maintenance calories.

The protein per kilogram figure is the suggested daily protein divided by your body weight in kilograms (pounds and stones are converted to kilograms first), rounded to one decimal place. If it comes out above 2.0 g/kg/day the result still shows, with a caution that individual needs vary.

Related tools

For a full breakdown of protein, carbohydrate and fat from a goal-adjusted calorie target, use the macro calculator. For BMR alone, see the BMR calculator.

Frequently asked questions

What is a protein intake calculator?

It suggests a daily protein target in grams, from your sex, age, height, weight and activity level. It also shows your estimated BMR and maintenance calories, and how your target compares to the general adult RDA minimum for your sex.

How is protein intake calculated?

Protein target (g/day) = body weight (kg) × grams per kilogram for your activity level, from 0.8 g/kg sedentary up to 2.2 g/kg for the most active band. Sex, age and height feed the Mifflin–St Jeor BMR and maintenance-calorie figures shown alongside the target, and set the RDA comparison point.

Why does sex matter for a protein calculator?

The grams-per-kilogram range itself is the same for men and women in the sports-nutrition literature — it is expressed per kilogram of body weight precisely so it already scales with body size. Sex instead changes the BMR and maintenance-calorie estimate (a different Mifflin–St Jeor constant for men and women) and the fixed RDA reference point — 56 g/day for adult men and 46 g/day for adult women, from the NASEM Dietary Reference Intakes.

Where do the grams-per-kilogram figures come from?

The 0.8 g/kg sedentary figure is the general adult Recommended Dietary Allowance (RDA) from the US/Canada Dietary Reference Intakes. The higher figures follow the International Society of Sports Nutrition position stand (Jäger et al., 2017), which recommends roughly 1.4 to 2.0 g/kg/day for exercising adults, rising towards 2.2 g/kg for the most active band.

What is the reference minimum, and should I just eat that instead?

The population reference minimum (56 g/day for men, 46 g/day for women) is the intake that prevents deficiency in most healthy sedentary adults. It is a baseline reference, not a personalised or optimal target, and not a recommendation to eat less than your activity-based figure. It is shown for context only.

When will this calculator not set a protein target?

It shows tailored-advice guidance instead of a number if you are under 18, or if you tick any of the pre-calculation questions: pregnant or breastfeeding, kidney disease or reduced kidney function, a health condition, prescribed diet or medication that may affect your nutrition needs, or a current or past eating disorder. In those situations protein and nutrition needs should be assessed individually by a qualified health professional. Being aged 65 or over does not, by itself, stop the calculator.

Is this calculator medical or dietary advice?

No. It is a general-information estimate for healthy adults, not a medical diet plan, a diagnosis, a treatment plan or a recommendation for kidney disease. Protein needs vary with age, body size, training, health and overall calorie intake. Speak to a GP or registered dietitian for advice tailored to you.

Is more protein always better?

No. Protein needs plateau — intake well above these figures generally does not add further benefit for muscle growth or health in most people, and very high intakes are not appropriate for everyone (for example, people with certain kidney conditions). These figures are a starting point, not a ceiling to maximise.

How does this compare to the macro calculator?

The macro calculator splits a full calorie target into protein, carbohydrate and fat together, based on your BMR, activity level and a lose/maintain/gain goal. This calculator focuses on protein alone, with its own activity-based grams-per-kilogram target and the RDA comparison.

Last updated 25 October 2026.