Protein Calculator: How Much Protein You Need Per Day

How the calculator works

Four steps, the same ones you could do on a napkin:

1. Convert to kilograms. Pounds divided by 2.2046. The research is written per kilogram, so the math is too.
2. Multiply by the number for your goal from the table below.
3. Round to the nearest 5 grams. Nobody can eat to the gram, and 5 g is less than one egg.
4. Divide by your meals to get grams per meal, again rounded to 5.

Two things the calculator does not do on purpose. It does not use "1 gram per pound" as the default, because that is the 2.2 g/kg ceiling, more than most people need; it shows up as the top of your range instead. And it does not set protein as a percentage of calories. Thirty percent of 1,600 calories is 120 g, thirty percent of 3,200 is 240 g, and your muscles did not change between the two. Protein follows bodyweight; calories follow everything else.

Two worked examples

170 lb, building muscle, four meals. 170 ÷ 2.2046 = 77.1 kg. 77.1 × 1.6 = 123 g, which rounds to 125 g a day. The range is 125 to 170 g (77.1 × 2.2 = 170). Split four ways, 125 ÷ 4 = 31, so about 30 g per meal. That is 500 calories of protein, at 4 calories per gram. One 30 g meal is about 3.5 oz (95 g) of cooked chicken breast or five large eggs.

150 lb, over 50, losing fat, three meals. 150 ÷ 2.2046 = 68 kg. 68 × 2.0 = 136 g, rounded to 135 g a day, with a range of 120 to 150 g. Over three meals that is 45 g each, comfortably above the 25 to 30 g per meal that matters most after 50. On a 1,700-calorie day, those 135 g are 540 calories, just under a third of the total. Fitting that much protein into fewer calories is a food-choice job; the list of high-protein, low-calorie foods ranked per 100 calories sorts it.

What changes your number

• Your goal. The biggest lever. The same 180 lb person needs 115 g to maintain, 130 g to build and 165 g to cut. The cutting number is higher because a deficit makes the body more willing to spend muscle; cutting without losing muscle covers the training side of that.
• Body fat. Grams per kilogram assumes most of your weight is not fat. At 280 lb with a lot of body fat, 205 g is more than your muscle needs. Enter a realistic goal weight instead, or take the bottom of the range on current weight; both usually land within 10 g of each other.
• Age. Older muscle responds less to a small dose, so the over-50 toggle keeps you at 1.6 g/kg or more and checks that each meal carries at least 25 g. The training matters as much as the food; strength training for women over 50 has the plan.
• Plant-based eating. Plant proteins are slightly less digestible and lower in leucine. The calculator has no vegan toggle; use the upper half of your range instead.
• Meals a day. Changes grams per meal, not the daily total. Three to five meals is the easy middle.

Sex is not on the list. Women and men use the same grams per kilogram; the totals differ only because bodyweight does.

What your number looks like as food

A gram of protein is not a gram of food. Cooked chicken breast is about 31% protein; the rest is mostly water. These are typical values from the USDA database for common portions:

The calculator uses three of these to translate your per-meal number: 8.8 g of protein per ounce of cooked chicken breast, 6 g per large egg, and 23 g per cup of nonfat Greek yogurt. Labels vary by brand, so check yours. For the rest of the supermarket, including the raw-versus-cooked difference, see what 100 g of protein looks like in food.

How to use the number

1. Write it down. One number for the day and one per meal, at the top of your food notes or your training log.
2. Build each meal around a protein food first, then add the rest. A meal that starts with 4 oz of chicken is already at 35 g.
3. Track for two weeks, then spot-check. Most people find the same gap: a 10 to 15 g breakfast. Fix that meal before anything else.
4. Judge the week, not the day. Within 10 g on most days is a hit. A short day followed by a normal one costs you nothing measurable.
5. Recalculate every 10 lb (about 5 kg) of change, or when your goal changes.

Protein is one line of the day. Your total calories decide whether you gain, hold or lose weight; the calorie calculator gives that number, and the macro calculator splits it into protein, carbs and fat with this target already in it. For complete days that hit a target with grams per item, see the 100 g protein meal plan.

Accuracy and limits

The output is a well-supported starting point, not a lab measurement. The 1.6 g/kg figure is where the average result in Morton's 2018 analysis leveled off; some people in those studies kept benefiting above it, which is why the calculator always shows a range up to 2.2 g/kg. If you eat at the top end comfortably, nothing is lost.

It does not know your body fat, your training volume or your appetite. It assumes you lift two to four days a week; if you do not train at all, the official RDA of 0.8 g/kg covers basic needs, and lifting is what makes the higher numbers pay off.

It is not for everyone. If you have kidney disease, have been told your kidney function is reduced, or take medication your doctor has linked to protein, ask your doctor before raising your intake. If you are pregnant or breastfeeding, set your target with your doctor or midwife. Teenagers who lift can use the same range, but from regular meals and with enough total food. For healthy adults, intakes up to about 2.2 g/kg have not been shown to cause harm in the research reviewed by the ISSN.

Questions people ask

Should I enter my current weight or my goal weight?

Current weight if you are within about 30 lb of where you want to be. If you carry a lot of body fat, enter a realistic goal weight; the result is lower, easier to eat and still enough for your muscle.

Why does the calculator give a range instead of one number?

Because the research does. The target is where most of the benefit is; the range shows how far either side still makes sense. Anywhere inside it is a reasonable day.

Is 1 gram per pound too much?

Not harmful for healthy adults, just more than most people need. It equals 2.2 g/kg, the top of the range. If it is easy for you, keep it; if you keep falling short, 0.7 g per lb gets nearly all the benefit.

Does protein from bread, rice and vegetables count?

Yes. Every gram counts toward the total. A day of grains, beans and vegetables can add 20 to 30 g without trying, which is why tracking often shows people closer to their number than they thought.

Is the protein calculator different for women?

No. The grams per kilogram are the same; a 140 lb woman and a 140 lb man get the same 100 g target to build muscle.

How much protein per meal is too much?

There is no hard cap. A 2023 study by Trommelen and colleagues found 100 g after training kept muscle building going longer than 25 g. Spreading protein over three to five meals is simply easier to eat, which is why the calculator divides it.

Where these numbers come from

• Morton and colleagues, protein supplementation and muscle mass and strength (British Journal of Sports Medicine, 2018): the 1.6 g/kg target and the 2.2 g/kg upper edge.
• International Society of Sports Nutrition position stand: protein and exercise (2017): 1.4–2.0 g/kg for people who exercise, higher in a deficit, and safety in healthy adults.
• Helms and colleagues, protein during caloric restriction in lean resistance-trained athletes (International Journal of Sport Nutrition and Exercise Metabolism, 2014): 2.3–3.1 g/kg of fat-free mass in a deficit. The calculator's 1.8–2.2 g/kg of bodyweight covers the lower part of that for a typical lifter; very lean people on a long diet can go higher.
• Bauer and colleagues for the PROT-AGE study group (Journal of the American Medical Directors Association, 2013): at least 1.2 g/kg for older adults who exercise, 25–30 g per meal.
• Trommelen and colleagues (Cell Reports Medicine, 2023): 100 g versus 25 g of protein after training.
• USDA FoodData Central: protein and calories for the foods in the table.