Protein Calculator — Daily Target for Fat Loss, Muscle Gain & Healthy Weight 2026
You hit your calorie goal. You lifted three times this week. But the number on the scale didn’t move — and your strength isn’t going up either. For most people, the missing variable isn’t effort. It’s protein. Not just how much, but whether the target is right for your body weight, your goal, and how your meals are distributed through the day.
Protein Calculator
Daily protein target · Meal timing · Food sources — science-based 2026
Enter your weight and goal to see your protein targets
This free protein calculator gives you a personalised daily protein target — minimum, recommended, and maximum benefit range — based on your body weight, activity level, biological sex, and primary goal. Add your body fat percentage for a lean-mass calculation that’s more accurate than weight alone. No signup. No supplement recommendations. No app required.
Most free protein calculators online still use the RDA figure of 0.8g per kg of body weight — a number set to prevent deficiency in sedentary adults, not to support muscle retention during fat loss or hypertrophy training. This calculator uses ISSN (International Society of Sports Nutrition) evidence-based ranges, updated for 2026.
What Is a Protein Calculator?
A protein calculator estimates your optimal daily protein intake in grams based on your body weight, activity level, biological sex, and goal — whether that’s losing fat while preserving muscle, gaining muscle mass, or maintaining your current physique. It translates research-backed protein-per-kilogram targets into a specific daily gram target for your body, removing the guesswork from one of the most important nutrition variables.
How to Use This Protein Calculator
Step 1 — Select Your Units and Biological Sex
Units: lbs/ft or kg/cm
Choose the unit system that matches how you measure your body weight. The calculator accepts both and converts internally for the protein-per-kilogram formula.
Biological Sex
Select Male or Female. Biological sex affects basal metabolic rate and muscle protein synthesis response — though the per-kg protein targets themselves are similar between sexes at equivalent activity levels and goals. Women may require slightly less total protein in absolute grams due to lower average lean body mass, but the formula per kilogram of body weight is consistent with current ISSN evidence.
Step 2 — Enter Body Weight
Should You Use Current Weight or Goal Weight?
For most people, use your current body weight. The exception: if you are significantly above your goal weight (BMI over 30), using your goal weight or estimated lean body mass gives a more accurate target — because protein needs are driven by muscle mass, not fat mass. This is where the optional body fat percentage field becomes useful.
Step 3 — Select Activity Level
How Activity Level Changes Your Protein Target
Activity level is one of the two biggest variables in protein calculation (alongside goal). Higher activity means more muscle protein breakdown that needs to be repaired — requiring more dietary protein to stay in net muscle balance.
The activity levels in this calculator correspond to:
- Sedentary — desk job, less than 7,000 steps/day, no structured exercise
- Lightly active — 1–3 days/week light exercise or consistent daily walking
- Moderately active — 3–5 days/week structured training (gym, sport, running)
- Very active — 6–7 days/week hard training or physically demanding job
- Extremely active — twice-daily training, elite athlete, or heavy manual labour
When in doubt, be honest rather than optimistic. Over-selecting activity level inflates your target without increasing your actual requirements.
Step 4 — Select Your Primary Goal
Fat Loss — Preserve Muscle While in a Deficit
Fat loss is where protein targets matter most. In a caloric deficit, your body is under pressure to use muscle tissue as an energy source — a process called gluconeogenesis. Higher protein intake during a deficit signals your body to preserve lean mass while burning fat. The ISSN recommends 1.6–2.4g per kg of body weight for fat loss phases, with the higher end of the range for more aggressive deficits or leaner individuals. This is 2–3× the standard RDA.
Muscle Gain — Building Mass
For muscle gain in a caloric surplus, the ISSN recommends 1.6–2.2g per kg for most trained individuals. The maximum benefit ceiling above which additional protein shows no further muscle-building effect is approximately 2.2g/kg for most people — though some elite athletes using body fat percentage for lean mass calculations may benefit from slightly higher targets.
Maintenance — Staying Healthy
Maintenance targets are lower than active muscle-building phases — approximately 1.2–1.6g per kg for active adults, and 1.0–1.2g/kg for lightly active individuals. The standard RDA of 0.8g/kg is the absolute minimum to avoid deficiency — not an optimal target for anyone doing regular exercise.
Step 5 — Body Fat Percentage (Optional)
Why Lean Mass Calculation Is More Accurate
Body fat percentage unlocks lean mass-based protein calculation — the most precise method available without a DEXA scan. The formula: Lean Body Mass (kg) = Total Weight × (1 − Body Fat %).
At 90kg and 25% body fat, your lean mass is 67.5kg. Your protein target is calculated on 67.5kg, not 90kg — a meaningful difference that prevents overestimating protein needs driven by fat tissue that does not require protein for maintenance. If you don’t know your body fat percentage, skip this field — the weight-based formula is accurate enough for most purposes.
How Much Protein Do You Actually Need?
The Science Behind the Calculator — ISSN 2026 Ranges
The International Society of Sports Nutrition Position Stand on protein and exercise is the most comprehensive evidence review available on daily protein targets. Key conclusions: for muscle retention and growth, 1.4–2.0g/kg/day is sufficient for most resistance-trained individuals, with the upper range (2.0–2.2g/kg) showing marginal additional benefit for advanced athletes or during aggressive cuts. For fat loss, 1.8–2.4g/kg protects lean mass during a deficit. For sedentary adults, the ISSN recommends 1.0–1.2g/kg even for lightly active individuals as a more appropriate baseline than the RDA.
The RDA Problem — Why 0.8g/kg Is the Wrong Number for Most People
The 0.8g/kg figure represents the minimum recommended value to prevent deficiency — it was never designed as a performance or body composition target. Research consistently shows this figure is insufficient for anyone doing resistance training more than twice per week, adults over 50 managing age-related muscle loss, anyone in a caloric deficit trying to preserve lean mass, or endurance athletes with high protein turnover from training volume. For these populations — which covers most people using a protein calculator — the evidence supports targets 1.5–3× above the RDA.
Protein Calculator for Weight Loss
Why Protein Is the Most Important Macro During a Deficit
When you cut calories, your body has two energy sources beyond dietary intake: fat stores and muscle tissue. The amount of protein you eat determines how much of each is used. At adequate protein intake (1.8–2.4g/kg), research consistently shows greater fat loss relative to muscle loss compared to higher-carbohydrate, lower-protein diets at the same calorie deficit. The mechanism: dietary protein stimulates muscle protein synthesis even in a deficit — signalling the body to preserve existing muscle while fat stores become the primary energy source.
Protein for Weight Loss — Female Considerations
Women often undereat protein relative to evidence-based targets — partly due to lower absolute calorie targets and partly due to cultural messaging. The ISSN recommendations apply equally to women: 1.6–2.4g/kg during active fat loss, regardless of sex. During a fat loss phase, a 65kg woman doing 4 days/week of resistance training needs approximately 104–156g of protein per day — not the 50–60g that basic calorie apps suggest at 1,200–1,400 calorie targets.
Protein for Weight Loss on GLP-1 Medications — Ozempic, Wegovy, Zepbound
GLP-1 receptor agonists (semaglutide, tirzepatide) significantly reduce appetite — often cutting food intake by 30–50%. This creates a protein intake problem: calorie restriction is higher than the person is aware of, and without deliberate protein prioritisation, substantial muscle loss accompanies the weight loss. Research from GLP-1 clinical populations in 2024–2025 suggests protein targets at the higher end of the ISSN range (2.0–2.4g/kg of goal body weight) during GLP-1 use, because muscle loss rates in GLP-1 trials without protein intervention run 25–40% of total weight lost.
If you are using Ozempic, Wegovy, Mounjaro, or Zepbound: use this calculator with your goal body weight, select the fat loss goal, and treat the maximum benefit figure as your daily target rather than the recommended figure.
Protein Calculator for Muscle Gain
How Much Protein Do You Need to Build Muscle?
The anabolic ceiling — the point above which additional protein adds no further muscle-building effect — is approximately 1.6–2.2g/kg/day for most trained individuals. Eating significantly above this range (3g/kg+) shows no additional muscle benefit and simply increases caloric intake. What matters more than hitting the upper ceiling is consistently meeting the floor: 1.6g/kg every day, not just on training days. Muscle protein synthesis remains elevated for 24–48 hours after resistance training, and inadequate protein during that window limits the adaptive response regardless of training quality.
Protein Timing for Muscle Gain
Per-meal protein distribution matters for consistency. This calculator’s Per-Meal Protein Guide shows your optimal per-meal target at 3, 4, 5, and 6 meals per day. Earlier guidance suggested a 20–25g per meal maximum absorption ceiling. More recent research (Trommelen et al., 2023) shows that larger protein doses do elevate MPS with the anabolic response persisting beyond 12 hours. The practical implication: total daily protein is the primary driver, but distributing 160g across 4 meals of 40g each is more achievable and consistent than hitting the same total in 1–2 meals.
Protein Calculator for Seniors (50+)
Why Protein Needs Increase After 50
Anabolic resistance — the reduced muscle protein synthesis response to a given protein dose — increases with age. A 70-year-old requires a higher protein dose per meal to achieve the same MPS response as a 30-year-old. The ISSN and ESPEN (European Society for Clinical Nutrition) both recommend 1.2–1.6g/kg for healthy older adults, rising to 1.6–2.0g/kg for older adults who are resistance training or managing sarcopenia. For seniors: select your current weight, choose your activity level honestly, and set your goal to Maintenance unless actively building muscle.
Sarcopenia Risk — Why Protein Matters More After 60
Sarcopenia (age-related muscle loss) progresses at approximately 1–2% per year after 50, accelerating after 70. It is the leading risk factor for falls, loss of independence, and reduced quality of life in older adults. The intervention with the strongest evidence for slowing sarcopenia is a combination of resistance training and adequate protein — specifically, 25–40g of high-quality protein per meal to overcome anabolic resistance.
Protein for Menopause and Perimenopause
Estrogen decline during perimenopause and menopause directly reduces muscle protein synthesis rates and accelerates fat redistribution. Evidence from menopause-specific nutrition research supports 1.4–1.8g/kg for perimenopausal and post-menopausal women — above the standard adult recommendation. Women in this phase should use the Muscle Gain or Maintenance goal rather than Fat Loss unless in an intentional deficit, as fat loss phases with inadequate protein during menopause accelerate muscle loss disproportionately.
Per-Meal Protein Guide — How to Hit Your Daily Target
Spreading Protein Across the Day
This calculator shows your per-meal target at 3, 4, 5, and 6 meals per day. Most people find 4–5 meals/day the easiest structure to hit a 140–180g daily target consistently. A practical 4-meal structure for a 160g/day target: Breakfast 40g (3-egg omelette + 200g Greek yogurt), Lunch 40g (150g chicken breast + lentils), Post-workout 25g (shake or tuna), Dinner 45g (200g salmon + edamame) — approximately 150g, with dietary variation filling the gap.
Top Protein Food Sources — Animal and Plant
Animal sources per serving:
| Food | Serving | Protein |
|---|---|---|
| Chicken breast | 100g cooked | 31g |
| Salmon | 100g | 25g |
| Tuna (canned) | 85g drained | 22g |
| Greek yogurt | 200g | 17g |
| Eggs | 1 large | 6g |
Plant sources per serving:
| Food | Serving | Protein |
|---|---|---|
| Tofu (firm) | 100g | 17g |
| Whey protein | 1 scoop (30g) | 25g |
| Edamame | 100g | 11g |
| Lentils | 100g cooked | 9g |
| Chickpeas | 100g cooked | 9g |
For plant-based eaters, hitting 140g+ protein per day requires deliberate planning — tofu, tempeh, edamame, lentils, and protein supplements are the high-density options.
Frequently Asked Questions
How much protein do I need per day?
For most adults doing regular exercise, daily protein needs range from 1.4g to 2.2g per kg of body weight — significantly higher than the RDA of 0.8g/kg, which is a minimum deficiency-prevention figure, not a performance target. A 75kg person doing 4 days/week of resistance training needs approximately 120–165g of protein per day. Use this calculator with your body weight, activity level, and goal for your personalised range.
How much protein do I need to build muscle?
The ISSN evidence base supports 1.6–2.2g/kg of body weight per day for muscle gain, with no meaningful additional benefit above 2.2g/kg for most individuals. A 80kg person training for muscle gain needs approximately 128–176g of protein daily. Consistency at 1.6g/kg every day outperforms occasional high-protein days followed by low-protein days.
How much protein do I need for weight loss?
During a caloric deficit, protein needs are higher than at maintenance — 1.8–2.4g/kg — because the body is under greater pressure to use muscle tissue for energy. A 70kg woman in a fat loss phase with resistance training needs approximately 126–168g of protein per day. Most calorie-deficit diets undersupply protein at this level without deliberate planning.
Does protein timing matter?
Total daily protein is the primary driver of muscle protein synthesis outcomes. Spreading protein across 3–5 meals of 25–40g each is practical and consistent with research. A post-workout protein intake within 2 hours of training has modest evidence for enhanced recovery but is less important than consistently hitting your daily total.
How much protein can your body use at one time?
The old 20–25g per meal ceiling has been revised. Research by Trommelen et al. (2023) shows that larger protein doses do elevate muscle protein synthesis, with the anabolic response persisting beyond 12 hours. Total daily protein is what matters most — but spreading intake across meals is more practical for most people.
Is 200g of protein a day too much?
For a 90kg+ active individual in muscle gain or fat loss, 200g falls within the ISSN recommended range (2.0–2.2g/kg). For a 70kg person, 200g exceeds the maximum benefit ceiling without adding further muscle-building effect. Excess protein in healthy individuals is used for energy, not stored. People with kidney disease should follow medical guidance on protein limits.
How much protein do women need per day?
Women need the same per-kilogram protein as men at equivalent activity and goal levels — approximately 1.4–2.2g/kg depending on goal. A 60kg woman training 4 days/week for muscle gain needs approximately 96–132g of protein per day. During menopause, the upper end of the range (1.6–1.8g/kg) is specifically supported by evidence on muscle retention.
What is the best protein source for muscle gain?
Animal proteins (chicken, fish, eggs, dairy) have the highest DIAAS scores — the most bioavailable essential amino acids per gram. Whey protein has the highest leucine content of any common source — relevant because leucine is the primary trigger of muscle protein synthesis. For plant-based diets, soy protein isolate and rice/pea protein blends are the closest to complete animal protein profiles.
Data Sources
Protein targets are based on the ISSN Position Stand: Protein and Exercise (2017, updated 2022), ESPEN guidelines on protein for older adults (2019), and clinical data on protein requirements during GLP-1 medication use (2024–2025). Food protein values sourced from USDA FoodData Central. Last verified: April 2026.
This calculator provides estimates for informational and educational purposes only. Results do not constitute medical or dietary advice. Individuals with kidney disease, liver disease, or other conditions affecting protein metabolism should consult a registered dietitian or physician before changing protein intake.
Related Calculators
- Calorie Deficit Calculator — Calculate your daily calorie target alongside your protein goal for fat loss or muscle gain
- Sleep Calculator — Recovery quality directly affects muscle protein synthesis — optimise both together
- BMR Calculator — Your basal metabolic rate determines the calorie foundation that protein targets build on