Protein Calculator
Estimate your daily protein target from your body weight, age, sex, activity level and goal. You get a sensible range in grams per day with a midpoint to aim for, the grams per kilogram it works out to, your RDA baseline, a per meal split, and an optional weekly food cost. Pregnancy, lactation and lean body mass options are built in.
Formula
Worked example
A 70 kg person building muscle uses 1.6-2.2 g/kg → 112-154 g per day, with a midpoint target of about 133 g; an extra-active multiplier nudges that a little higher.
How much protein do you need?
Protein needs scale with body weight and activity. The official Recommended Dietary Allowance (RDA) for sedentary adults is 0.8 grams per kilogram of body weight per day, enough to prevent deficiency. People who train, especially for strength, need more to repair and build muscle: sports-nutrition bodies commonly cite 1.2-2.0 g/kg, and up to around 2.2-2.4 g/kg when building muscle or dieting to preserve it. This calculator multiplies your weight by the range for your chosen goal, then nudges it for how often you train. You can also switch to the official RDA method, which reads your minimum straight from the age and sex tables.
Activity, life stage and lean body mass
Training frequency moves your target within the goal range, since someone lifting six days a week needs more than a casual gym-goer at the same body weight. Pregnancy and breastfeeding raise needs further: the calculator adds the recommended extra protein for each trimester and for the first and later months of lactation. If you carry a lot of body fat, basing protein on lean body mass rather than total weight gives a lower and often more accurate figure, so an optional body fat percentage lets you switch the basis.
Why timing and spread matter
Total daily protein matters most, but distribution helps. Muscle protein synthesis responds to roughly 20-40 grams of high-quality protein per meal, so spreading intake across three or four meals tends to beat loading it all at once. The per-meal figure and the meal plan table divide your target into equal servings as a practical guide, and you can set how many meals you eat.
Protein quality, sources and cost
Animal proteins, eggs, dairy, meat and fish, contain all essential amino acids in ample amounts. Plant proteins such as beans, lentils, tofu and grains can fully meet needs too, especially when varied across the day so their amino acid profiles complement each other. Most people can reach their target through food; supplements are a convenience, not a requirement. Turn on the cost estimate to see a rough weekly spend: whole-food protein typically runs about 0.02 to 0.05 per gram, while whey powder is often cheaper per gram.
Protein guidance by goal
| Goal | Protein (g/kg) | Example at 70 kg |
|---|---|---|
| Sedentary (RDA) | 0.8-1.0 | 56-70 g |
| Generally active | 1.2-1.4 | 84-98 g |
| Endurance training | 1.4-1.6 | 98-112 g |
| General athlete | 1.4-2.0 | 98-140 g |
| Building muscle | 1.6-2.2 | 112-154 g |
| Losing fat | 1.6-2.4 | 112-168 g |
Grams of protein per kilogram of body weight, based on sports-nutrition guidance. The RDA for sedentary adults is 0.8 g/kg.
Frequently asked questions
Should I use the goal method or the RDA method?
Use the goal method if you exercise or want to build or keep muscle, it gives a higher, performance-oriented range in grams per kilogram. Use the RDA method if you just want the official minimum to avoid deficiency for your age and sex. The RDA is a floor, not a target for active people.
Is too much protein harmful?
For healthy people, intakes up to around 2 g/kg are considered safe in the research literature. Very high intakes are not generally harmful but offer little extra benefit. People with kidney disease should follow medical advice, as their needs differ.
Should I base protein on total or lean body weight?
Total body weight is fine for most people. If you carry a lot of excess fat, basing protein on lean body mass (weight minus fat) gives a lower and often more accurate figure. Switch the basis to lean body mass and enter a body fat percentage to use that approach.
How much extra protein do I need when pregnant or breastfeeding?
Guidance adds about 1 g/day in the first trimester, 10 g/day in the second, and 31 g/day in the third, plus about 19 g/day while breastfeeding in the first six months and 13 g/day after that. Select your stage and the calculator adds it automatically.
Does this replace medical advice?
No. These are general estimates from sports-nutrition guidance and official reference intakes for healthy people. Pregnancy, illness and kidney conditions change protein needs, consult a doctor or dietitian for personalised advice.