To calculate your protein needs, multiply your body weight in kilograms by a factor that matches your activity level and goals. For a sedentary adult, that factor is 0.8 grams per kilogram of body weight, which works out to about 0.36 grams per pound. A 170-pound person with a desk job, for example, needs roughly 61 grams of protein per day at this baseline. But that number is a minimum to prevent deficiency, not an optimal target, and most people benefit from eating more.
The Basic Formula
Start by converting your weight to kilograms. Divide your weight in pounds by 2.2. Then multiply by the gram-per-kilogram figure that fits your situation:
- Sedentary adults: 0.8 g/kg (the RDA minimum)
- Recreationally active adults: 1.0–1.2 g/kg
- Athletes and regular exercisers: 1.6–2.4 g/kg
- Adults over 65: 1.0–1.2 g/kg
- People losing weight: 0.7–1.0 g per pound of body weight
Here’s a quick example. A 180-pound person who exercises regularly would divide 180 by 2.2 to get about 82 kilograms, then multiply by 1.6 to get roughly 131 grams of protein per day as a starting point.
Why the RDA Is a Floor, Not a Target
The RDA of 0.8 g/kg was set to prevent protein deficiency in the general population. It represents the minimum amount a sedentary adult needs to avoid losing muscle, not the amount that supports optimal health, body composition, or physical performance. Most nutrition researchers now consider it too low for anyone who exercises, is trying to lose fat, or is over 65.
Another way to frame protein needs: federal dietary guidelines set the acceptable range at 10 to 35 percent of total daily calories for adults. On a 2,000-calorie diet, that’s anywhere from 50 to 175 grams. The wide range reflects just how much individual needs vary depending on goals and circumstances.
How Much Protein Athletes Need
If you strength train, run, cycle, or do any structured exercise several times a week, your protein needs are roughly double the RDA. A consensus across sports nutrition research puts the range at 1.6 to 2.4 grams per kilogram of body weight per day. For a 170-pound person, that translates to about 123 to 185 grams daily.
The lower end of that range (1.6 g/kg) is enough for most people looking to build or maintain muscle with regular resistance training. The higher end (closer to 2.4 g/kg) becomes more relevant when you’re training hard while also cutting calories, since extra protein helps preserve lean mass when your body is in an energy deficit.
Per-meal dosing matters too. Your body can maximally stimulate muscle repair with about 20 to 30 grams of protein per meal, roughly 0.25 to 0.30 grams per kilogram of body weight per sitting. For someone weighing 80 kilograms, that means spreading intake across four or more meals rather than loading it all into dinner.
Adjusting for Weight Loss
When you’re eating fewer calories than you burn, your body doesn’t just pull energy from fat. It also breaks down muscle tissue, which slows your metabolism and makes regaining weight easier. Protein is the main tool for preventing that.
Guidelines for muscle preservation during a calorie deficit are higher than the standard RDA: about 0.7 to 1.0 grams per pound of body weight. A 150-pound person cutting calories would aim for 105 to 150 grams of protein daily. That’s a meaningful amount, and spreading it across meals matters. Your body can effectively use about 30 grams of protein from a single meal for muscle maintenance, so three large meals plus a snack is a more effective strategy than one or two protein-heavy meals.
Protein Needs After 65
Adults over 65 lose muscle mass gradually, a process called sarcopenia that accelerates with age and inactivity. This natural decline means older adults actually need more protein per kilogram than younger sedentary adults, not less. Researchers recommend 1.0 to 1.2 grams per kilogram of body weight for older adults, paired with regular resistance and endurance exercise to help the protein do its job.
A 160-pound person over 65 would aim for roughly 73 to 87 grams per day. As with weight loss, distributing protein evenly across meals improves how well the body uses it. A breakfast of just toast and coffee leaves a big gap that’s hard to make up at dinner.
When to Use Lean Body Mass Instead
All the formulas above are based on total body weight, which works well for people at a roughly average body composition. But if you carry significantly more body fat, your total weight overstates how much protein you need, because fat tissue doesn’t require protein for maintenance the way muscle does.
Researchers have advocated for calculating protein needs based on fat-free mass (your weight minus your body fat) rather than total weight, particularly for people with obesity. The formula used in research is about 1.5 grams per kilogram of fat-free mass. If you know your body fat percentage from a scale, DEXA scan, or even a rough estimate, you can subtract that fat weight from your total weight and use the remainder as your baseline. For example, a 250-pound person at 40% body fat has about 150 pounds (68 kg) of lean mass, which would put their protein target around 102 grams per day rather than the 182 grams you’d get using total weight at 1.6 g/kg.
If you don’t know your body fat percentage and you’re significantly overweight, a simpler approach is to use your goal weight or a healthy reference weight in the formula instead of your current weight.
Estimating Protein in Real Food
Once you have a daily target, the next step is knowing what’s actually on your plate. A standard cooked portion of chicken, fish, or lean beef is 3 ounces, roughly the size of a deck of cards, and contains about 21 to 25 grams of protein. From there, the math gets practical:
- One egg: about 6 grams
- One cup of milk (low-fat): about 8 grams
- Six ounces of yogurt (low-fat): about 9 grams (Greek yogurt can have 15 to 18)
- Half cup of cooked beans or lentils: about 7 to 9 grams
- 3 ounces of cooked chicken breast: about 26 grams
- 3 ounces of cooked salmon: about 22 grams
If your target is 130 grams, that might look like three eggs at breakfast (18 g), a cup of Greek yogurt as a snack (17 g), a chicken breast at lunch (40 g), a cup of lentil soup in the afternoon (15 g), and a piece of salmon with beans at dinner (40 g). That gets you to 130 grams without any supplements, though a protein shake can fill gaps on days when whole food meals fall short.
Putting It Together
The calculation itself takes about 30 seconds. Divide your weight in pounds by 2.2, then multiply by the g/kg factor that matches your life. The harder part is being honest about which category you fall into. Someone who walks a few times a week is closer to the sedentary baseline than the athlete range. Someone doing intense CrossFit sessions five days a week while cutting weight is at the top of the range.
If you’re unsure, 1.2 to 1.6 grams per kilogram is a reasonable middle ground for most active adults. It’s well above the deficiency-prevention minimum, covers the needs of moderate exercisers, and aligns with the ranges supported by the broadest body of evidence. Start there, track how you feel, and adjust up or down based on your goals and how your body responds.