Protein Calculator
Grams of protein a day from your weight, your training and your goal, with the range the research supports and what the target looks like as food.
Protein Calculator
Past 65 the floor rises. Older muscle responds less to the same dose of protein, so the lower end of the band moves up.
Total body weight is the default because that is how nearly every trial reports its dose. Switch to lean mass if you are carrying a lot of fat, where scaling against the scale figure overshoots.
Fill this in and the panel shows what share of your day the protein takes. Leave it blank and everything else still works.
The range, end to end
| Level | Grams/day | g per kg | g per lb | Per meal |
|---|---|---|---|---|
| Lower end | – | – | – | – |
| Target | – | – | – | – |
| Upper end | – | – | – | – |
What your target looks like as food
Each row is how much of that food alone would cover the whole day. Nobody eats one food all day; the point is the scale of the portions.
Two people weigh 80 kg. One lifts five days a week and is six weeks into a cut. The other has a desk job and walks the dog. The first wants about 180 g of protein a day. The second does nothing wrong at 80 g. Same reading on the scale, more than double the target, and what separates them is training rather than body size.
Where each band came from
The floor is 0.8 g per kilogram of body weight. That figure sits in the US and European dietary reference intakes, and it was set to stop nitrogen balance going negative in adults who do not train. It is a deficiency threshold. Reading it as a goal is like reading the minimum wage as a salary target.
Above the floor, the numbers come from four separate bodies of work. Morton and colleagues pooled 49 resistance-training trials in 2018 and found gains in lean mass flattening out at 1.62 g/kg a day. The International Society of Sports Nutrition puts 1.4 to 2.0 g/kg on anyone training regularly. Endurance work lands lower, 1.2 to 1.6, because running does not create the same repair demand that loading a muscle does. And the PROT-AGE group raised the floor to 1.0 to 1.2 g/kg for healthy adults past 65, then higher again for older people who train, which is why the panel asks your age.
Pick strength training and hold your weight, and the calculator gives you 1.6 to 2.2 g/kg. At 80 kg that is 128 to 176 g, with the headline figure at 152.
Why it prints a range
Morton’s 1.62 g/kg has a 95 percent confidence interval running from 1.03 to 2.20. That is the honest width of the finding. A tool that prints 1.62 and stops has thrown away the most useful part of the result, which is how much room there is inside it.
So the headline here is the midpoint of a band and the table shows both ends. Anywhere in that band works. The gap between the bottom and the top of your range is smaller than the gap between hitting your target four days a week and hitting it seven, and the second one is the problem most people actually have.
Cutting calories raises the number
A deficit is the one goal that reliably moves the requirement up, and the panel adds 0.4 g/kg when you select it. When energy is short the body will take amino acids from muscle to cover the gap, and a high protein intake is what makes that unnecessary. Trials getting the best body-composition results under restriction run 2.0 to 2.4 g/kg with resistance training attached, and the recomposition page sets out the other conditions those trials imposed, which were not gentle ones.
There is a second reason, less discussed and just as practical. Protein is the most filling of the three macros per calorie. At 2.2 g/kg a 2,000 kcal day feels survivable in week nine. At 1.0 g/kg the same 2,000 kcal does not. Work out what your maintenance figure is first with the calorie calculator, then come back and set protein against your body weight rather than against those calories.
Lean mass against total body weight
Use total body weight. Nearly every trial dosed protein against the scale figure, so that is the basis the research was built on, and switching basis for the sake of precision usually swaps a studied number for an unstudied one.
One exception is worth the extra input. Someone at 130 kg and 40 percent body fat is carrying 52 kg of fat mass, and fat mass has no protein requirement. At 2.0 g/kg of total weight the calculator asks that person for 260 g a day, which is a lot of food for no reason. Scaled against 78 kg of lean mass it asks for 156 g, and the second figure is the defensible one. The lean-mass bands are higher per kilogram for exactly that reason: Helms and colleagues reviewed protein intake in lean resistance-trained athletes under caloric restriction and recommended 2.3 to 3.1 g per kg of fat-free mass, which is the top edge of the whole literature and applies to a narrow group of people. If you need a body fat figure, the body fat calculator gets one from a tape measure.
Per meal, and how much the timing matters
Absorption is not the limit anyone should worry about. Your gut will take up almost all of a 100 g serving given enough hours. What has a ceiling is how much of a single dose gets used for building muscle, and Schoenfeld and Aragon put that near 0.4 g per kilogram per meal, so roughly 32 g for an 80 kg person. Four meals at that size covers 1.6 g/kg without trying.
That is the whole case for spreading it out, and it is a modest one. The daily total does most of the work. Eating 150 g across two meals instead of four costs you something measured in single-digit percentages, which is worth knowing and not worth rearranging your day over. The per-meal column exists so you can see whether your meals are big enough, not so you can set alarms.
Can you eat too much
Healthy kidneys handle high intakes without difficulty. Devries and colleagues pooled 28 trials in 2018 and found no effect of high protein diets on kidney function in adults who started with healthy kidneys. Antonio’s group ran trained lifters at 4.4 g/kg for eight weeks, more than double the top of any recommendation on this page, and found no change in blood lipids, liver or kidney markers.
The real cost of overshooting is opportunity. Every gram of protein is 4 kcal that could have been carbohydrate fuelling your training, and chicken is more expensive than rice. Past about 2.5 g/kg you are paying for insurance against a risk that has already been covered. Existing kidney disease changes this answer completely, and that conversation belongs with a doctor.
Where this stops
The bands here describe healthy adults who train or do not train. Pregnancy, kidney disease, liver disease, dialysis and recovery from major surgery all shift protein requirements, sometimes sharply up and sometimes sharply down, and none of them belong to a calculator. Children and teenagers grow on different figures again.
Protein quality sits outside the arithmetic too. Eighty grams from eggs, dairy and meat is not the same 80 g from bread and rice, because plant sources are generally lower in leucine and short on one or two essential amino acids each. Eating plant-based is perfectly workable and usually means running the higher end of your band and mixing sources across the day. The protein guide works through what the research covers and what it leaves open, and the macro calculator takes the figure from this page and fits carbohydrate and fat around it.
Scope and correction note, 10 October 2026: The meta-analyses and position stands linked above are published research. The way their ranges are combined into the bands this panel prints is an editorial judgement, and the food values come from USDA FoodData Central. Nothing here is medical or dietetic advice. See the editorial policy and medical disclaimer.
Common questions
How much protein do I need a day?
If you lift three to five days a week, 1.6 to 2.2 g per kilogram of body weight covers it, which is 112 to 154 g at 70 kg. If you train nothing in particular, 0.8 to 1.2 g/kg is enough, so 56 to 84 g at the same weight. Cutting calories pushes the band up by about 0.4 g/kg, because protein is what keeps a deficit from taking muscle along with the fat.
How much protein do I need to build muscle?
Around 1.8 to 2.4 g per kilogram, with the training to justify it. Morton and colleagues pooled 49 resistance-training studies in 2018 and found gains in lean mass flattening out near 1.62 g/kg, so most of the benefit arrives before 2.0. An 80 kg lifter is looking at 144 to 192 g a day. Going to 3 g/kg has been tested and it does not add anything except expense.
How much protein should I eat to lose weight?
More than you would at maintenance. Run 2.0 to 2.4 g/kg while calories are short, which is 150 to 180 g for a 75 kg person. Two things happen at that intake: you keep more of your lean mass through the diet, and you stay fuller on fewer calories, since protein is the most satiating of the three macros per calorie. Both of those matter more in week nine than in week one.
Is 100 grams of protein a day enough?
It depends entirely on what you weigh. At 60 kg, 100 g is 1.67 g/kg and sits right in the range for someone who lifts. At 100 kg it is 1.0 g/kg, which clears the government minimum and falls short of what a lifter wants. The number on its own tells you nothing, which is why every figure on this page is per kilogram.
Can you eat too much protein?
Healthy kidneys handle high intakes without trouble. Trials running 2.5 to 3.3 g/kg for months, including one that went to 4.4 g/kg, found no change in kidney function or bone health. The real cost is opportunity: every gram of protein is 4 kcal that could have been carbohydrate fuelling your training. Existing kidney disease changes the answer completely, and that conversation belongs with a doctor rather than a calculator.
How much protein can your body absorb in one meal?
Absorption is not the limit. Your gut will take up almost all of a 100 g serving given enough hours. What has a ceiling is how much of a single dose goes into building muscle, and that plateaus somewhere around 0.4 g per kilogram per meal, so roughly 30 g for a 75 kg person. Spreading the day across three or four meals clears that threshold each time. Eating it all at dinner still counts toward your total.
How much protein per kilogram of body weight?
0.8 g/kg is the floor every dietary reference intake sets, and it was calculated to prevent deficiency in sedentary adults. 1.2 to 1.6 suits endurance athletes. 1.6 to 2.2 suits anyone training with weights. 2.0 to 2.4 is where fat-loss trials run. Past 2.5 g/kg the research shows no further benefit for body composition in people who are not already very lean.
Should I use total body weight or lean body mass?
Total body weight, unless you are carrying a lot of fat. Nearly every trial dosed protein against the scale figure, so that is the basis the numbers were built on. The exception matters though: at 130 kg and 40 percent body fat, 2.0 g/kg of total weight asks for 260 g a day, and the 52 kg of fat mass in that total has no protein requirement at all. Scaling against lean mass gives 156 g, which is the more defensible target.
Do protein needs change with age?
Yes, and they go up. Older muscle responds less to the same dose, a blunting that shows up clearly past 65. The PROT-AGE group recommends 1.0 to 1.2 g/kg for healthy older adults and 1.2 to 1.5 for those who train or have an illness to recover from, against the 0.8 the general guidelines set. Per-meal size matters more here too, because each sitting has to clear a higher threshold to trigger anything.
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