Most adults need between 0.8 and 1.6 grams of protein per kilogram of body weight each day, depending on age, activity level, and goals. For a 150-pound person, that translates to roughly 55 to 109 grams of protein daily. The wide range exists because a sedentary office worker and someone lifting weights four days a week have very different needs. Below, you’ll find the multipliers for each situation so you can calculate your own number in seconds.
The Simple Calculation
Every protein recommendation starts with the same formula: your body weight in kilograms multiplied by a factor that reflects your lifestyle. To convert your weight to kilograms, divide your weight in pounds by 2.2. Then multiply by the factor that best fits your situation:
- Sedentary adult: 0.8 g/kg (the official Recommended Dietary Allowance)
- Recreationally active adult: 1.0–1.2 g/kg
- Strength training or building muscle: 1.2–1.6 g/kg
- Adult over 65: 1.0–1.3 g/kg
- Losing weight while preserving muscle: 1.2–1.6 g/kg
So a 180-pound man (about 82 kg) who lifts weights regularly would aim for roughly 98 to 131 grams per day. A 140-pound woman (about 64 kg) who jogs a few times a week would target 64 to 77 grams.
Why the RDA Is a Floor, Not a Target
The RDA of 0.8 g/kg was set to prevent deficiency in the general population. At that level, protein supplies as little as 10% of total daily calories. It keeps you from losing muscle in a clinical sense, but it’s not optimized for fitness, aging, or body composition. Think of it as the minimum to avoid problems, not the amount that helps you thrive.
For most people who exercise, eat in a calorie deficit, or are over 50, the research consistently points to intakes above the RDA. A large meta-analysis published in the British Journal of Sports Medicine found that protein intakes beyond 1.6 g/kg per day produced no additional muscle gain in people doing resistance training. That 1.6 g/kg mark appears to be the practical ceiling for muscle-building benefits.
Adjustments for Age
Older adults lose muscle more readily and use dietary protein less efficiently. Researchers now recommend that adults over 65 consume 1.0 to 1.2 grams per kilogram daily to maintain muscle strength and physical function. The Chinese Nutrition Society updated its guidelines in 2023 to reflect this same range, moving away from the traditional 0.8 g/kg recommendation for older populations. For a 180-pound older man, that works out to about 82 to 98 grams per day.
If you’re over 65 and also doing resistance training, aiming closer to 1.3 to 1.6 g/kg may be appropriate. Muscle-related outcomes consistently improve at intakes of 1.2 g/kg and above, though benefits start to plateau past 1.6 g/kg.
Adjustments for Weight Loss
When you eat fewer calories than you burn, your body breaks down both fat and muscle for energy. Eating more protein tilts the balance toward fat loss while sparing lean tissue. This is why most sports nutrition guidelines recommend 1.2 to 1.6 g/kg during a calorie deficit, significantly higher than the baseline RDA.
The practical difference matters. A 200-pound person cutting calories at 0.8 g/kg gets about 73 grams of protein. At 1.4 g/kg, they get 127 grams. That extra protein helps preserve the muscle you already have, keeps you feeling fuller between meals, and supports a higher metabolic rate throughout the dieting phase.
Should You Use Total Weight or Lean Mass?
If you’re at a relatively normal body fat percentage, calculating protein from your total body weight works fine. But if you carry a significant amount of extra body fat, using total weight can overestimate your needs. Fat tissue doesn’t require the same protein support that muscle, bone, and organs do.
A more accurate approach for higher body fat levels is to base your intake on lean body mass. A woman weighing 160 pounds with roughly 100 pounds of lean mass, for example, would target around 100 grams of protein per day rather than 160. If you don’t know your lean mass, a reasonable workaround is to use your goal weight or an estimated “ideal” weight for the calculation instead of your current weight.
How to Spread Protein Across the Day
Your body can digest and absorb large amounts of protein in a single sitting, but muscle-building signals respond best when protein is distributed throughout the day. Research suggests that eating 20 to 25 grams of protein every three to four hours optimizes the muscle-building response in younger adults. For someone eating four meals a day, that means roughly 0.4 to 0.55 grams per kilogram at each meal.
In practical terms, if your daily target is 120 grams, you’d aim for about 30 grams at each of four meals rather than eating 10 grams at breakfast and 80 grams at dinner. This doesn’t need to be exact. The key point is that skewing all your protein into one meal leaves muscle-building potential on the table for the rest of the day. Older adults benefit from this even more, since their muscle tissue requires a stronger protein signal to activate repair and growth.
Plant-Based Protein Needs an Adjustment
If most or all of your protein comes from plants, you may need to eat slightly more total protein to get the same benefit. Plant proteins are typically 75 to 80% digestible, compared to 90 to 95% for animal proteins like eggs, meat, and dairy. Compounds naturally found in legumes, grains, and seeds can reduce how much protein your body actually absorbs.
This doesn’t mean plant protein is inadequate. It means a vegan eating at the 0.8 g/kg minimum might effectively be getting closer to 0.6 g/kg in usable protein. Adding roughly 10 to 20% more total protein compensates for the difference. Combining different plant sources (rice with beans, hummus with whole grain bread) also helps cover all essential amino acids. At intakes around 1.15 g/kg per day, research shows that the differences between plant and animal protein sources become minimal.
Upper Limits and Safety
High-protein diets are not known to cause medical problems in healthy people. The concern about protein damaging kidneys applies specifically to people who already have kidney disease, because their kidneys struggle to clear the waste products of protein metabolism. If your kidneys function normally, intakes up to about 2.0 g/kg per day are generally considered safe, though there’s little evidence of added benefit beyond 1.6 g/kg for muscle-related goals.
Going above 2.0 g/kg per day isn’t necessarily dangerous, but nutrition experts flag it as a zone where caution is reasonable. At very high intakes, protein can crowd out other important nutrients, and the extra calories still count toward your daily total. For most people, the sweet spot falls well below that threshold.
Quick Reference by Body Weight
Here are sample ranges for common body weights, spanning from the sedentary baseline (0.8 g/kg) to the active upper range (1.6 g/kg):
- 120 lbs (55 kg): 44–88 grams per day
- 140 lbs (64 kg): 51–102 grams per day
- 160 lbs (73 kg): 58–117 grams per day
- 180 lbs (82 kg): 66–131 grams per day
- 200 lbs (91 kg): 73–146 grams per day
- 220 lbs (100 kg): 80–160 grams per day
Pick the multiplier that matches your activity level and goals from the list above, and you’ll land on a number that’s far more personalized than any generic recommendation.