Protein Calculator: How Much Protein Do I Need a Day?

How to use the protein calculator

Enter your age, height, weight and activity level, then pick your goal: stay healthy, lose fat and keep muscle, on a GLP-1 medicine, or build muscle. You’ll get a daily range in grams, a middle target to aim for, and that target split across three, four or five meals.

Below your number, the calculator builds a sample day from everyday foods like Greek yogurt, eggs, chicken, tuna, tofu and lentils. Switch to vegetarian to see plant and dairy options only.

How your protein target is calculated

Protein needs are set in grams per kilogram of body weight per day (g/kg). The calculator picks a range for your goal, adjusts it for age and training, then multiplies by your weight.

Daily protein

Protein (g) = weight basis (kg) × g/kg range for your goalAge 65+: range is at least 1.0 to 1.2 g/kgVery active or athlete: add 0.2 g/kg to both endsBMI over 30: weight basis = weight at BMI 25 + 25% of the weight above it

Why the adjustment above BMI 30? Fat tissue needs very little protein, so multiplying total weight overshoots. Using an adjusted weight is a common clinical-nutrition method, and the 2025 joint advisory on nutrition for GLP-1 therapy also recommends adjusted or lean-mass-based targets for people with obesity.

Example: 200 lb (90.7 kg) at 5 feet 5 inches has a BMI of about 33. Weight at BMI 25 is 68 kg, so the basis is 68 + 0.25 × 22.7 = about 74 kg. For fat loss at 1.2 to 1.6 g/kg, that’s roughly 88 to 118 grams a day, with a target near 103 grams.

How much protein do you need? Ranges by goal

These are the ranges the calculator uses before any adjustments.

Daily protein by goal (grams per kg of body weight)
Goal	g per kg	Per lb	Why
Stay healthy	0.8–1.0	0.36–0.45	Covers basic needs for most adults
Lose fat, keep muscle	1.2–1.6	0.54–0.73	Helps protect muscle in a calorie deficit
On a GLP-1 medicine	1.2–1.6	0.54–0.73	Smaller appetite makes it easy to fall short
Build muscle	1.6–2.2	0.73–1.0	Supports gains with resistance training
Age 65+	At least 1.0–1.2	0.45–0.54	Muscle responds less to protein with age

0.8 g/kg is the long-standing minimum (the RDA). The Dietary Guidelines for Americans, 2025–2030, now suggest 1.2 to 1.6 g/kg for adults, so aiming at the top of the “stay healthy” range or higher is reasonable for most people.

Why protein matters more when you’re losing weight

When you eat less, your body can pull from muscle as well as fat. Losing muscle lowers your daily burn, weakens you and makes regain more likely. Protein, together with strength training, is the best-studied way to limit it. A 2022 meta-analysis of 74 trials found that eating more protein gave a small but real boost in lean mass when paired with resistance exercise.

Protein also keeps you full. Gram for gram it tends to satisfy more than carbs or fat, which makes a deficit easier to hold.

On a GLP-1 medicine? These medicines shrink appetite, and many people end up eating too little protein without noticing. The 2025 joint advisory from four obesity and nutrition societies recommends 1.2 to 1.6 g/kg a day during active weight loss (or about 80 to 120 grams if that’s easier to track), plus strength training. Eat protein first at each meal, before you feel full.

Spreading protein across the day

Your body uses protein best in steady doses, not one big dinner. For most adults that means roughly 25 to 40 grams at each main meal. Many people eat little protein at breakfast and most of it at night, so breakfast is usually the easiest place to add.

Protein in everyday foods (USDA FoodData Central, rounded)
Food	Portion	Protein
Chicken breast	5 oz cooked	44 g
93% lean ground beef	5 oz cooked	37 g
Salmon	5 oz cooked	36 g
Firm tofu	8 oz	36 g
Tuna	1 can	27 g
Cottage cheese	1 cup	25 g
Protein shake	1 scoop	24 g
Greek yogurt	1 cup	23 g
2 eggs + 2 egg whites	1 serving	19 g
Edamame or lentils	1 cup	18 g

Want it planned for you? The 7-day high-protein meal plan hits high protein at every calorie level from 1,200 to 2,400, with a grocery list.

Who should be careful with high protein

For healthy adults, the ranges above are well within safe limits. Talk with your clinician first if you have chronic kidney disease, advanced liver disease or a history of kidney stones, or if you’re pregnant, since your needs may be different. Drink enough water as protein goes up; the water intake calculator can help.

This calculator gives an estimate, not a prescription. It doesn’t know your lab results, your kidney function or how much muscle you carry.

Protecting muscle with GENEVA

At GENEVA Primary Care & Med Spa in Alpharetta, we track what matters during weight loss: a body-composition scan shows whether you’re losing fat or muscle, and labs check kidney function, blood sugar, thyroid and hormones. Low testosterone and menopause both make muscle harder to keep, so our men’s health and women’s health teams can look at the hormone side.

If you qualify, your plan can include prescription weight loss medicine such as GLP-1 medicines, with protein and strength targets built in from day one. These medicines are generally for a BMI of 30 or more, or 27 or more with a weight-related condition, and a clinician decides. Learn about medical weight loss at GENEVA, or set your calories first with the TDEE and calorie deficit calculators. Results vary.

Frequently asked questions

How much protein do I need to lose weight?

Most adults losing weight do well with 1.2 to 1.6 grams per kilogram of body weight a day, or about 0.55 to 0.73 grams per pound. If your BMI is over 30, base it on an adjusted weight rather than your full weight. The calculator does both.

How much protein should I eat on a GLP-1 medicine?

A 2025 joint advisory recommends 1.2 to 1.6 g/kg a day during active weight loss, or roughly 80 to 120 grams a day. Eat protein first at each meal and pair it with strength training to protect muscle.

Is 100 grams of protein a day too much?

For most healthy adults, no. It’s a common target during weight loss. People with kidney disease should check with their clinician first.

Should I use my current weight or goal weight?

If your BMI is 30 or under, current weight works. Above 30, the calculator uses an adjusted weight (weight at BMI 25 plus a quarter of the extra), which lands between current and goal weight.

How much protein can the body absorb at once?

Your body absorbs nearly all the protein you eat. What changes is how much goes to building muscle at one time. Spreading 25 to 40 grams over each meal is a practical way to use it well.

Can I get enough protein as a vegetarian?

Yes. Greek yogurt, cottage cheese, eggs, tofu, tempeh, edamame, lentils and beans can cover it. Switch the calculator to vegetarian to see a sample day.

Do protein shakes help with weight loss?

They’re a convenient way to reach your target, especially at breakfast or when appetite is low. Whole foods add fiber and nutrients, so use shakes to fill gaps, not replace every meal.

Do older adults need more protein?

Yes. Muscle responds less to protein with age, so the calculator raises the range to at least 1.0 to 1.2 g/kg at 65 and older. Strength training matters just as much.

Sources

This tool gives general estimates for healthy adults and is not medical advice, a diagnosis or a treatment plan. It is not meant for anyone pregnant, under 18, or managing a medical condition without their clinician. Talk to a GENEVA provider before making big changes to how you eat, drink or exercise.

Protein Calculator how much protein you need a day