🍖 Protein Calculator
How much protein you need a day, from the bare minimum for health to the range that preserves muscle while you are losing weight. The answer is a range, and where you sit in it depends on what you are asking your body to do.
How much protein you actually need, and why the RDA is a floor
The official recommended intake is 0.8 grams of protein per kilogram of body weight a day. That figure is often read as a target when it was derived as a minimum: the amount that prevents deficiency in most sedentary adults. It is the nutritional equivalent of the lowest temperature at which pipes do not freeze, and it is not where you would set the thermostat.
Daily protein = body weight (kg) × grams per kg for your goal
| Situation | Grams per kg | For a 78 kg adult |
|---|---|---|
| RDA, sedentary minimum | 0.8 | 62 g |
| General health, active | 1.2 – 1.6 | 94 – 125 g |
| Building muscle | 1.6 – 2.2 | 125 – 172 g |
| Losing fat, preserving muscle | 1.8 – 2.4 | 140 – 187 g |
| Over 65, countering muscle loss | 1.2 – 1.5 | 94 – 117 g |
The International Society of Sports Nutrition's position stand puts 1.4 to 2.0 g/kg as sufficient for most exercising people, with higher intakes useful during a calorie deficit. The reason the deficit range is the highest on the table is that protein is what the body preserves muscle with when total energy is short.
Why a deficit needs more, not less
When you eat fewer calories than you burn, the body draws on stored energy — and it does not draw exclusively on fat. Some of the loss comes from muscle unless two signals say otherwise: enough protein in the diet and enough mechanical load on the muscle. Without those, a substantial share of the weight lost is lean tissue, which lowers resting metabolism and makes the weight easier to regain.
This is the most practically useful fact on the page. Someone cutting calories with the calorie deficit calculator should raise protein as calories fall, not lower it, and should keep lifting something heavy twice a week. The macro calculator fits the protein target inside a calorie budget.
Distribution across the day
Muscle protein synthesis responds to a dose, and the response saturates. The position stand recommends roughly 0.25 g per kg per meal, or an absolute 20 to 40 g, with each dose containing 700 to 3,000 mg of leucine — the amino acid that acts as the trigger. Beyond that, extra protein in one sitting is still used, but for energy and tissue turnover rather than for additional muscle building.
The practical consequence is that 140 g spread across four meals of 35 g each does more for muscle than the same 140 g delivered as a token breakfast and an enormous dinner. Three or four doses across the waking day is the pattern with the best support, and the gap between distributions is modest rather than dramatic — total intake still matters most.
Protein targets use body weight, but for someone carrying a lot of excess fat, scaling from total weight overshoots, because fat tissue has little protein requirement. In that case base the calculation on a weight at the top of the healthy BMI range, or on lean mass from the body fat calculator.
What the targets look like as food
| Food | Serving | Protein |
|---|---|---|
| Chicken breast | 100 g | 31 g |
| Beef mince, 5% fat | 100 g | 26 g |
| Salmon | 100 g | 25 g |
| Greek yoghurt, 0% | 170 g pot | 17 g |
| Eggs | 2 large | 13 g |
| Lentils, cooked | 200 g | 18 g |
| Tofu, firm | 150 g | 17 g |
| Whey protein | 1 scoop, 30 g | 24 g |
Hitting 140 g without planning is harder than it sounds: it is roughly a chicken breast, two eggs, a pot of Greek yoghurt, a scoop of whey and a portion of lentils across a whole day. Most people who think they eat plenty of protein are somewhere between 70 and 100 g, because bread, rice and pasta contribute far less than their volume suggests.
Is high protein bad for your kidneys?
In people with healthy kidneys, intakes up to around 2 g/kg and beyond have not been shown to cause kidney damage in controlled studies, including trials running two years in resistance-trained adults. The concern originates in advice given to people who already have reduced kidney function, for whom protein restriction is genuinely part of treatment. Extrapolating that advice to healthy people is a well-documented error.
That said, more protein does mean more nitrogen to excrete and more water needed to do it, so hydration rises with intake — see the water intake calculator. And anyone with existing kidney or liver disease should treat protein targets as a medical question rather than a fitness one.
A worked example
A 78 kg man lifting three times a week in a mild calorie deficit sets his target at 1.8 g/kg, or 140 g a day, spread as four meals of 35 g. That is 20% of a 2,400 calorie budget (protein supplies four calories per gram, so 140 g is 560 calories), leaving 1,840 for carbohydrate and fat. At 2.4 g/kg he would be at 187 g and 748 calories, which starts to crowd out the carbohydrate that fuels the training itself — which is why the upper end of the range is a ceiling rather than a goal.
If this is one step in a larger decision, the macro calculator is usually the next question, and the TDEE calculator is worth a look while you are here.
Frequently Asked Questions (FAQs)
How much protein do I need a day?
The RDA is 0.8 g per kg of body weight, which is a deficiency-prevention minimum. Active people generally do better at 1.2 to 1.6 g/kg, those building muscle at 1.6 to 2.2 g/kg, and those losing fat while preserving muscle at the top of that range or slightly above.
Is the RDA of 0.8 g/kg enough?
Enough to avoid deficiency, which is what it was designed for. It is not the amount associated with best outcomes for muscle retention, satiety or healthy ageing, and nearly every sports nutrition body recommends more for anyone who trains.
Can I eat too much protein in one meal?
You can eat more than will contribute to muscle building in one sitting — the response saturates around 0.25 g/kg, or 20 to 40 g. The surplus is not wasted; it is simply used for energy and tissue turnover instead. Spreading intake across three or four meals is better, but total daily intake matters more.
Does high protein damage your kidneys?
There is no evidence of harm in people with healthy kidneys at intakes up to and beyond 2 g/kg, including in multi-year trials. The advice to restrict protein applies to people who already have reduced kidney function, and should not be generalised to everyone.
Should I eat more protein when losing weight?
Yes. A calorie deficit costs muscle as well as fat unless protein is high and you are training. Raising protein as calories fall is one of the few changes that reliably improves body composition during weight loss, and it also helps with hunger.
Do older adults need more protein?
Most researchers in the field think so. Muscle becomes less responsive to protein with age, so the same dose does less, and 1.2 to 1.5 g/kg is commonly recommended over 65 to slow the loss of muscle and the loss of independence that follows it.
Is plant protein as good as animal protein?
Per gram it is usually slightly less effective, because plant sources tend to be lower in leucine and less digestible. The gap closes with a modestly larger serving and variety across the day, so a well-planned plant-based diet reaches the same targets — it simply needs more planning.