If you’ve searched “how much protein do I need” and landed on five different numbers, you’re not imagining things. Protein needs aren’t one-size-fits-all — they shift based on your body weight and height, activity level, your age, and goals.
This guide gives you two ways to calculate your protein needs:
-
- a simple body-weight method,
- a more precise calorie-based method using the Mifflin-St Jeor equation (old on tight because this walks through the meticulous calculation, or you can scroll to the bottom for a quick calculation).
We’ll also walk through how your target shifts if you’re looking to maintain your current status, if you are working with insulin resistant, on a GLP-1 medication, or actively working toward weight loss.
The Quick Method: Grams Per Kilogram of Body Weight
The fastest way to estimate your protein needs is based on your current body weight in kilograms (weight in pounds/2.2=weight in kilograms).
Based on this quick calculation your weight in kilograms is multiplied by a factor depending on your goals. That factor ranges from 0.8g/kg/day up to 2.0g/kg/day (see below for more details).
For Example: A person weighing 165 lbs (75 kg) who is working on weight loss would aim for roughly 90–120 grams of protein per day.
165 lbs / 2.2 = 75kg
75kg multiplied by a factor of 1.2-1.6g = 90-120 grams of protein per day
This method is a great starting point, but it doesn’t account for your total calorie intake — which matters a lot if you’re working in a calorie deficit, managing blood sugar, or eating less overall due to appetite suppression from medication. That’s where the Mifflin-St Jeor equation comes in.
A More Precise Method: Mifflin-St Jeor Equation + Calorie Percentage
The Mifflin-St Jeor equation is considered one of the most accurate calculation to estimate your basal metabolic rate (BMR). The BMR is the number of calories that you burn at complete rest, just to maintain vital functions. After knowing BMR, you adjust for your activity level to find your total daily energy expenditure (TDEE).
Step 1: Calculate Your BMR (Basal Metabolic Rate)
This is the Mifflin St. Jeor equation, if you want to have fun calculating it.
For men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
For women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
Step 2: Adjust for Activity Level (Find Your TDEE)
Multiply your BMR by an activity factor:
-
- Sedentary (little to no exercise): BMR × 1.2
- Lightly active (light exercise 1–3 days/week): BMR × 1.375
- Moderately active (moderate exercise 3–5 days/week): BMR × 1.55
- Very active (hard exercise 6–7 days/week): BMR × 1.725
Step 3: Set Protein at 20–30% of Total Calories
Once you know your TDEE, protein calories are calculated as a percentage of that number, then converted to grams (protein has 4 calories per gram).
Formula: (TEE × protein percentage) ÷ 4 = grams of protein per day
Example: A 45-year-old woman, 165 lbs (75 kg), 5’6″ (168 cm), moderately active:
-
- BMR = (10 × 75) + (6.25 × 168) − (5 × 45) − 161 = 1,439 calories
- TDEE = 1,439 × 1.55 = 2,230 calories
- At 25% of calories from protein: (2,230 × 0.25) ÷ 4 = ~139 grams of protein/day
Where You Fall on the 20–30% Range — And Why It Matters
The 20–30% range isn’t arbitrary — where you land depends on what’s going on in your body and what you’re working toward.
If You Have Insulin Resistance: Aim for 25–30%
Higher protein intake within this range helps blunt post-meal blood sugar spikes, improves satiety (which reduces the odds of overeating carbohydrates later), and supports more stable energy throughout the day. Pairing protein with fiber-rich carbohydrates at each meal amplifies this effect.
If You’re on a GLP-1 Medication: Aim for 25–30%, and Prioritize Total Grams
This is the population where protein intake matters most and gets missed most often. GLP-1 medications suppress appetite so effectively that total food intake — and therefore total protein — often drops well below what’s needed to protect lean muscle mass.
On a GLP-1, hitting the percentage-of-calories target matters as much as hitting your gram target consistently, even in small, spaced-out amounts across the day, since appetite may only allow for small meals.
If You’re Working Toward Weight Loss: Aim for 25–30%
In a calorie deficit, protein does double duty:
-
- it preserves lean muscle mass (which protects your basal metabolic rate)
- it’s the most satiating macronutrient, which makes the deficit easier to sustain
Which Method Should You Use?
-
- Use the g/kg method if you want a fast, reliable starting number and aren’t tracking calories closely.
- Use the Mifflin-St Jeor + percentage method if you’re already tracking intake, working with a calorie target, or need more precision because you’re managing insulin resistance, using a GLP-1 medication, or in an active weight-loss phase.
Both methods should land you in a similar range. If they don’t, that’s usually a sign your activity level or goal category needs a second look. This is exactly the kind of thing worth working through with a dietitian rather than guessing.
Get the Details for Your Specific Situation
This page covers the math and the general framework. For a deeper, situation-specific breakdown, see:
The Bottom Line
Protein needs aren’t static, and “just eat more protein” isn’t personalized advice. Your target should reflect your body weight, your calorie needs, and what your body is currently working through. Start with the g/kg estimate, refine it with the calorie-based method if you want more precision, and adjust the percentage based on where you fall.
Want your exact number? Try our free protein calculator for a target based on your weight and activity level.
