- How much protein do I need per day?
- The Recommended Dietary Allowance (RDA) is 0.8 grams of protein per kilogram of body weight per day — that's the minimum to prevent deficiency in a sedentary adult, roughly 56 g for a 70 kg person. Most people who exercise, are trying to build muscle, are losing weight, or are older benefit from more: commonly 1.2–2.0 g/kg. This calculator multiplies your weight by the range that matches your goal.
- What protein range should I use for building muscle?
- The International Society of Sports Nutrition and the Academy of Nutrition & Dietetics recommend roughly 1.6–2.2 g/kg per day to build and maintain muscle when you're doing resistance training. Going much above ~2.2 g/kg hasn't been shown to add extra muscle for most people. If you're in a calorie deficit and want to protect muscle, the upper end (up to ~2.4 g/kg) can help.
- Why does the calculator give a range instead of one number?
- Because the science supports a band, not a single point. Within each goal there's a low end (enough) and a high end (optimal for that goal), and where you land depends on training intensity, age, and whether you're gaining or losing weight. We show the range and a sensible midpoint to aim for.
- Is a high-protein diet bad for your kidneys?
- For people with healthy kidneys, current evidence does not show that higher protein intakes in the ranges here cause kidney damage. But if you have kidney disease or another medical condition, protein needs are different and often lower — talk to your doctor or a dietitian. This tool is general guidance, not medical advice.
- Does it matter if protein comes from plants or animals?
- You can meet your target on a fully plant-based diet — it just takes a little planning, because most plant foods are lower in protein per serving and some are lower in the amino acid lysine. Eating a variety of legumes, soy (tofu, tempeh, edamame), seitan, grains, nuts and seeds across the day covers all the essential amino acids. The calculator lists both animal and plant portions so you can see what hits your number.
- How should I split protein across the day?
- Muscle protein synthesis responds best when protein is spread across meals rather than loaded into one, so we divide your target by the number of meals you set (default four). Landing roughly 20–40 g per meal is a practical goal for most adults.
- Is the protein calculator free and private?
- Yes. It's free, there's no sign-up, and every calculation runs entirely in your browser — your weight and goal are never uploaded. Your last inputs are saved only to this browser's local storage for convenience.