Turning your weight into a number.
Protein targets are given per kilogram of body weight, which is convenient and mostly sensible — until you're carrying a lot of fat, at which point the standard arithmetic quietly overshoots.
The basic sum
Multiply your body weight in kilograms by a figure from the range that fits your situation:
| Situation | g per kg / day |
|---|---|
| Sedentary, no specific goal | 0.8 – 1.0 |
| Generally active | 1.2 – 1.6 |
| Resistance training, building muscle | 1.6 – 2.0 |
| Losing fat, protecting muscle | 1.6 – 2.4 |
| Over 60 | 1.0 – 1.2 |
Worked example. A 78 kg person who lifts three times a week, aiming for the middle of the muscle-building range:
78 × 1.8 = 140 g of protein a day.
In pounds. The rule of thumb in the US is that grams per pound is roughly half the grams-per-kg figure — 1.6 g/kg lands near 0.7 g/lb, and the familiar "one gram per pound" is about 2.2 g/kg. That's at the top of the useful range rather than the middle: not harmful, just more than most people need. If you prefer exact numbers, divide your weight in pounds by 2.205 to get kilograms first.
The adjustment most calculators skip
Body fat is not metabolically demanding tissue. It doesn't need feeding with protein the way muscle does. So when someone is carrying a substantial amount of it, scaling protein to total body weight produces a number that's higher than the evidence supports.
A concrete case. A 130 kg man at roughly 40% body fat has about 78 kg of lean mass. Scaling to total weight at 1.8 g/kg gives 234 g of protein a day. Scaling to lean mass gives about 140 g. The first number is punishing to eat and isn't supported by better outcomes.
There are two reasonable ways to handle this, and they land in a similar place:
- Use lean body mass if you have a decent body-fat estimate, at roughly 1.8–2.2 g per kg of lean mass.
- Use goal weight — the weight you're heading toward — with the normal multipliers. Cruder, but it needs no measurement and gets you close.
If you're at a broadly typical body composition, none of this matters much and total body weight is fine. The correction only becomes significant above roughly 30% body fat.
A quick reference
Daily protein in grams, for common weights:
| Body weight | × 1.2 | × 1.6 | × 2.0 |
|---|---|---|---|
| 55 kg / 121 lb | 66 g | 88 g | 110 g |
| 65 kg / 143 lb | 78 g | 104 g | 130 g |
| 75 kg / 165 lb | 90 g | 120 g | 150 g |
| 85 kg / 187 lb | 102 g | 136 g | 170 g |
| 95 kg / 209 lb | 114 g | 152 g | 190 g |
| 105 kg / 231 lb | 126 g | 168 g | 210 g |
Don't over-tune it
It's tempting to treat this as a precision exercise. It isn't. The ranges above are wide because the underlying research is genuinely uncertain at the edges, and because individual variation is real.
What actually determines your result is how many days you land near the number — not whether the number is 138 or 145. A target of 140 g hit five days a week beats a meticulously calculated 137 g hit twice.
So round it. Pick something memorable — 120, 140, 160 — and spend your attention on the eating rather than the arithmetic.
One number, one square a day
Set your goal once. PRO.TEIN can also read your latest weight from Apple Health to suggest one, then shows how you're doing as a calendar you can read in a second.
This is general information, not medical advice. If you have kidney or liver disease, diabetes, are pregnant or breastfeeding, or are managing any medical condition, your protein needs may differ substantially — speak to a doctor or registered dietitian before changing your diet.