What is protein and why do you need it?

Protein is one of the three main nutrients that provide calories, along with carbohydrate and fat. Your body uses protein to build and repair muscle, skin, hair and organs, and to make enzymes and hormones. Unlike some other nutrients, your body does not keep a large store of protein, so you need a steady supply from food every day.

This calculator turns the research-based guidelines into a personal daily range. You enter your weight and choose the goal that fits you best, and it shows how many grams of protein to aim for, how that divides across your meals, and what share of your calories that is.

How much protein do adults need?

The Recommended Dietary Allowance (RDA) for healthy adults is 0.8 grams of protein per kilogram of body weight per day. In pounds, that is about 0.36 grams per pound. The RDA is the amount that meets the basic needs of nearly all healthy adults, so many people eat somewhat more than this, and some groups are advised to eat more.

Protein is also described as a share of your total calories. The Acceptable Macronutrient Distribution Range (AMDR) for adults is 10 to 35 percent of daily calories from protein. Each gram of protein supplies about 4 calories, so you can move between grams and calories with simple math.

Protein by goal

Goal	Grams of protein per kg per day	Grams per lb per day
General health (adults)	0.8 to 1.0	0.36 to 0.45
Adults over 65	1.0 to 1.5	0.45 to 0.68
Regular exercise or sport	1.2 to 2.0	0.54 to 0.91

The lower number in the first row is the RDA. Researchers who study ageing have suggested that older adults do better with more protein, partly because muscle becomes less responsive to protein with age. Fact sheets from the U.S. National Institutes of Health give 1.2 to 2.0 grams per kilogram as the range athletes typically need for training and recovery.

How to use this calculator

1. Choose US or metric units and enter your weight.
2. Select the goal that fits you.
3. Enter how many meals you usually eat. The default is three.
4. If you know your daily calories, enter them to see what share of your calories the protein is. This box is optional.
5. Press Calculate. The numbers also update as you change your answers.

Worked examples

Example 1: general health. An adult who weighs 70 kg (154 lb) and wants to meet the basics. At 0.8 to 1.0 grams per kilogram, the range is 56 to 70 grams a day. Over three meals, that is about 19 to 23 grams per meal.

Example 2: regular exercise. An adult who weighs 80 kg (176 lb) and trains most days. At 1.2 to 2.0 grams per kilogram, the range is 96 to 160 grams a day. Because the range is wide, it makes sense to start near the lower end and move up only if it helps your training and you feel well.

Example 3: over 65. An adult who weighs 65 kg (143 lb). At 1.0 to 1.5 grams per kilogram, the range is 65 to 98 grams a day, which is about 22 to 33 grams over three meals.

How much protein is in common foods?

These are approximate amounts. Food labels give exact numbers for packaged foods.

Food	Approximate protein
1 large egg	6 g
1 cup low-fat milk	8 g
Greek yogurt, 7 oz (200 g) low-fat	20 g
3 oz (85 g) cooked chicken breast	26 g
1/2 cup firm tofu	10 g
1 cup cooked lentils	18 g

Tips for getting enough protein

• Include a protein food at every meal, not only at dinner.
• Mix animal and plant sources, such as fish, eggs, dairy, beans, lentils, tofu and nuts.
• Choose protein foods that are not heavily processed when you can.
• If you add a protein shake or bar, treat it as a supplement to real meals, not a replacement.
• If you are active, spread protein through the day and eat enough total calories and carbohydrate to fuel your training.

Complete and incomplete proteins

Protein is made of building blocks called amino acids. Your body can make some of them, but nine, called essential amino acids, must come from food. Animal foods such as eggs, dairy, fish and meat contain all nine in useful amounts. Many plant foods are lower in one or more of them, but that is not a problem when you eat a mix of plant proteins over the day, for example beans with rice, or hummus with whole-grain bread.

Protein, hunger and weight management

Protein tends to make meals more filling than the same number of calories from refined carbohydrate, which is one reason many weight management plans emphasize it. When people eat fewer calories to lose weight, getting enough protein also helps protect muscle. This is why the calculator is useful to pair with our Calorie Calculator, but it is still best to focus on whole, minimally processed foods rather than on protein products.

Remember that protein supplies calories too. Eating well above your needs adds calories that your body may store as fat, just like extra calories from any other nutrient.

Spreading protein through the day

Many people eat very little protein at breakfast and a large amount at dinner. Some experts suggest a more even pattern, with a protein food at each meal, because the body can only use so much for muscle repair at one time. If you tend to skip breakfast protein, easy options include eggs, yogurt, cottage cheese, nut butter on toast, or tofu scramble.

Who should be careful

The ranges on this page are for healthy adults. People with kidney disease, liver disease or other medical conditions should follow the advice of their own doctor or dietitian, because their protein needs may be different. The same applies if you are pregnant or breastfeeding, under 18, or following a special diet prescribed by a health professional. Very high protein intakes over long periods have not been proven to give extra benefits for most people.

Frequently asked questions

How much protein do I need per day?

For most healthy adults the Recommended Dietary Allowance is 0.8 grams of protein per kilogram of body weight, which is about 0.36 grams per pound. Older adults and people who exercise regularly are often advised to eat more, within the ranges this calculator shows.

Is more protein always better?

No. Once you meet your needs, extra protein does not automatically build more muscle, and calories from protein count like any other calories. The accepted range for adults is 10 to 35 percent of daily calories.

Can I get enough protein from plant foods?

Yes. Beans, lentils, tofu, nuts, seeds and whole grains all provide protein. Eating a variety of plant foods across the day helps you get all the building blocks your body needs.

How much protein should I eat at each meal?

Many nutrition experts suggest spreading protein across the day, with roughly 25 to 30 grams at a meal for the average adult. This calculator divides your daily range by the number of meals you enter.

Is my information saved?

No. All calculations happen in your browser. Your weight and calorie numbers are never sent to our server or stored.

Helpful resources

• Optimizing Protein Intake in Adults: RDA compared with the Acceptable Macronutrient Distribution Range, a review in Advances in Nutrition
• Dietary Supplements for Exercise and Athletic Performance from the NIH Office of Dietary Supplements
• Our Calorie Calculator and BMI Calculator

This calculator is for general information only. It is not medical or nutrition advice and cannot diagnose any condition. Talk to a qualified health professional before you change your diet. See our Terms & Disclaimer.