This free protein calculator works out your daily protein target from body weight, body fat, diet type and training goal — using International Society of Sports Nutrition ranges rather than one generic number for everyone. Enter your details below; the explanation of how the numbers are derived is underneath the tool.
200+ FCS Protein System
How Much Protein Do I Need a Day?
Most people asking how much protein do I need a day get one of two useless answers: a flat number that ignores body size, or a bodybuilding figure that assumes everyone is bulking. The honest answer is a range tied to body weight and training goal. The International Society of Sports Nutrition position stand puts it roughly here:
- General health and maintenance: 1.4–2.0 g per kg of body weight
- Building muscle: 1.6–2.2 g per kg
- Cutting while preserving lean mass: 2.2–3.0 g per kg
The three ISSN brackets the calculator works from. Cutting sits highest, not lowest.
That is why this protein calculator asks for your goal rather than handing you one number. A 70 kg person maintaining general health and a 70 kg fighter in camp are not eating the same amount, and treating them the same is how people either under-recover or waste money on protein they cannot use.
How This Protein Intake Calculator Works
Built for martial artists, fighters, and anyone training seriously. Three things separate it from a basic protein intake calculator:
Lean Body Mass algorithm
Most calculators use total body weight, which overestimates protein needs for anyone carrying higher body fat. Enter your body fat percentage and this tool strips adipose tissue out of the equation to work from your true lean mass, then applies a higher multiplier (up to 2.8 g per kg of LBM when cutting) to protect muscle.
Protein timing and leucine
Daily total is only half of it. The calculator splits your target across meals and shows the per-meal window (0.4–0.55 g/kg) plus the 1.7–3.5 g leucine threshold that triggers muscle protein synthesis. Hitting the total but stacking it into one meal leaves results on the table.
Diet type adjustments
Plant proteins digest less efficiently and often lack a complete amino acid profile (lower DIAAS). Selecting omnivore, vegetarian, or vegan changes both the suggested food sources and the recovery guidance — for example prioritising soy, tempeh, and seitan to reach leucine targets on a plant-based diet.
Why diet type changes the plan: reaching the same daily total takes noticeably more volume on plant sources.
Building Muscle vs Losing Fat
How much protein do I need to build muscle?
Around 1.6–2.2 g per kg of body weight. Past roughly 2.2 the returns flatten out hard — more protein does not become more muscle. At that point training stimulus and sleep are the limiting factors, not intake, and the extra grams are just expensive calories.
Using the protein calculator for weight loss
The counter-intuitive part: protein goes up, not down, when you are cutting. Anyone using a protein calculator for weight loss and picking a low number is doing the opposite of what the evidence supports.
In a calorie deficit your body will pull amino acids from wherever it can find them, and muscle is an available source. Higher protein intake plus resistance training is what tells it to spare that tissue and take the energy from fat instead. That is the entire reason the cutting bracket sits at 2.2–3.0 g/kg while maintenance sits near 1.4–2.0.
Protein is not a substitute for training. Hitting your number every day with no progressive overload produces very little. The calculator supports the training — it does not replace it. Pair it with our water intake calculator, since higher protein loads increase your hydration requirement.
Protein Calculator FAQ
Should I use total body weight or lean body mass?
If you know your body fat percentage reasonably accurately, lean body mass gives a better figure — especially at higher body fat levels, where total-weight formulas can overshoot significantly. If you are guessing at your body fat, leave the field blank and use total weight. A confident wrong number is worse than no number.
Do I need to hit the exact number every day?
No. Weekly consistency matters far more than daily precision. Landing within roughly 10% of your target most days is the practical goal — chasing an exact gram count tends to make people give up entirely.
Why does it split my target into several meals?
Muscle protein synthesis responds to each feeding rather than to the daily total alone. Spreading intake across four or more meals, each clearing the leucine threshold, keeps that response switched on through the day instead of spiking once.
Can I reach these numbers on a vegan diet?
Yes, with more planning. Plant proteins score lower on digestibility, so aim toward the top of your range and lean on soy, tempeh, and seitan, which carry the most leucine per serving. Select Vegan in the calculator and it adjusts the guidance for you.
Is a high protein intake safe?
For healthy adults, intakes in these ranges are well tolerated in the research. Water needs rise with protein intake, which is why the tool flags hydration on the higher brackets. If you have kidney disease, are pregnant, or manage any medical condition, treat these figures as a starting point for a conversation with a doctor or registered dietitian rather than a target to adopt on your own.