Your daily protein target depends on your body weight, activity level, and life stage. The simplest starting formula: multiply your weight in pounds by 0.36 (or your weight in kilograms by 0.8). That gives you the baseline minimum in grams per day. For a 160-pound person, that’s about 58 grams. But this baseline is designed for sedentary adults and is likely too low if you exercise regularly, are trying to lose weight, or are over 65.
The Baseline Calculation
The Recommended Dietary Allowance for protein is 0.8 grams per kilogram of body weight, which works out to 0.36 grams per pound. The World Health Organization frames it slightly differently: 10 to 15 percent of total daily calories, or roughly 50 to 75 grams for someone eating about 2,000 calories a day. Both approaches land in a similar range for average-weight adults who aren’t particularly active.
Here’s the math step by step:
- In pounds: Your weight × 0.36 = daily protein in grams
- In kilograms: Your weight × 0.8 = daily protein in grams
If you only know your weight in pounds, divide by 2.2 to get kilograms. A 180-pound person weighs about 82 kg, giving a baseline of roughly 65 grams of protein per day. This number represents the minimum to prevent deficiency, not necessarily the amount that’s optimal for your goals.
Adjusting for Exercise and Muscle Goals
If you lift weights, run, cycle, or do any regular structured exercise, your protein needs climb well above the baseline. Most sports nutrition guidelines recommend 1.2 to 1.6 grams per kilogram for active adults, and up to 2.0 grams per kilogram for people doing intense resistance training.
The math works the same way. A 150-pound person (68 kg) aiming for 1.6 g/kg would need about 109 grams of protein daily, nearly double the baseline recommendation. If you’re unsure where you fall on the activity spectrum, 1.2 g/kg is a reasonable starting point for anyone who exercises a few times a week.
Protein Needs During Weight Loss
When you’re eating fewer calories than you burn, protein becomes even more important. It helps preserve muscle while your body draws on fat stores for energy. A study from McMaster University tested this directly: young men eating 40 percent fewer calories than they needed were split into two groups, one eating 1.2 g/kg of protein and the other eating 2.4 g/kg. Both groups did intense exercise. After four weeks, the higher-protein group gained 1.2 kg of lean mass and lost 4.8 kg of fat. The lower-protein group barely changed their muscle mass and lost less fat (3.5 kg).
If you’re cutting calories and exercising, aiming for 1.6 to 2.4 g/kg of body weight gives you the best shot at losing fat without losing muscle. For a 170-pound person (77 kg), that’s 123 to 185 grams per day. This is significantly more than the standard recommendation, but the context is different: your body needs extra protein to repair and maintain muscle tissue when energy is scarce.
Over 65: Higher Targets to Prevent Muscle Loss
Aging bodies become less efficient at turning dietary protein into muscle. This is one reason muscle mass declines steadily after middle age, a process called sarcopenia. Research from Stanford Lifestyle Medicine recommends that adults over 65 aim for 1.2 to 2.0 grams of protein per kilogram of body weight per day, substantially higher than the standard 0.8 g/kg.
For a 150-pound older adult (68 kg), that translates to 82 to 136 grams per day. Spreading protein evenly across meals seems to matter more with age, since older muscles need a stronger signal from each meal to trigger repair. Three meals each containing 25 to 40 grams of protein is more effective than loading most of your protein into dinner.
Pregnancy and Breastfeeding
Protein needs increase during pregnancy, but the jump is modest in early months and larger toward the end. In the first trimester, you need only about 1 extra gram of protein per day beyond your normal intake. In the second trimester, that rises to roughly 9 extra grams. By the third trimester, the additional requirement climbs to 28 to 31 extra grams per day, reflecting the rapid growth happening in the final months.
During breastfeeding, the extra demand stays elevated. Exclusively breastfeeding mothers need roughly 19 to 23 additional grams of protein daily for the first six months. After six months, when solid foods enter the picture, the extra need drops to about 12 to 13 grams per day.
Plant-Based Diets Need a Bump
Not all protein is created equal when it comes to how well your body can absorb and use it. Animal proteins like eggs, dairy, meat, and fish deliver all the essential amino acids in highly digestible form. Milk protein concentrate, for example, scores 1.18 on the digestible indispensable amino acid score (the current gold standard for measuring protein quality), while a corn-based cereal scores just 0.01.
Diet modeling studies show that whole-food plant-based diets generally have lower protein quality and amino acid density than omnivorous or lacto-ovo-vegetarian diets. If you eat exclusively plant-based, you may need to eat more total protein to compensate. A practical approach is to add 10 to 20 percent on top of whatever target you calculate. So if your goal is 80 grams, aim for 88 to 96 grams. Eating complementary proteins throughout the day (grains with legumes, nuts with seeds) also helps fill amino acid gaps.
Upper Limits and Safety
For most healthy adults, keeping protein intake at or below 2.0 g/kg of body weight is a sensible ceiling. That’s about 125 grams per day for a 140-pound person. Going higher isn’t necessarily dangerous in the short term, but chronically very high protein diets are associated with a higher risk of kidney stones. High-protein diets that rely heavily on red meat also carry links to increased risk of heart disease and colon cancer, though this likely has more to do with the type of protein than the amount.
If you have existing kidney disease, high protein intake can accelerate damage. But for people with healthy kidneys, intakes up to 2.0 g/kg appear safe based on current evidence.
Putting It All Together
Start with the basic formula (weight in kg × 0.8) and then adjust based on your situation:
- Sedentary adult: 0.8 g/kg
- Regularly active: 1.2 to 1.6 g/kg
- Intense training or weight loss with exercise: 1.6 to 2.4 g/kg
- Over 65: 1.2 to 2.0 g/kg
- Pregnant (third trimester): normal intake plus 28 to 31 grams
- Breastfeeding: normal intake plus 19 to 23 grams
- Plant-based eaters: add 10 to 20 percent to your calculated target
Once you have your number, the easiest way to check whether you’re hitting it is to track a few typical days of eating using a food tracking app or nutrition label math. Most people fall into consistent eating patterns, so you don’t need to track forever. A few days of honest logging will tell you whether you’re undershooting, overshooting, or right on target.