Protein Intake Calculator — Daily Target, Free
Calculate daily protein need from weight, age, activity level, goal. Evidence-based ranges. Browser-only.
About Protein Intake Calculator
Protein intake recommendations vary by goal: sedentary adults need ~0.8 g/kg body weight (RDA, US NIH), active people 1.2-1.6 g/kg, strength athletes 1.6-2.2 g/kg, elderly adults 1.0-1.2 g/kg to preserve lean mass. The ZTools Protein Intake Calculator computes a personalized target based on weight, activity level, and goal (maintenance, muscle gain, weight loss, elderly). Outputs in grams per day and grams per meal (for 3-5 meals). Sources: International Society of Sports Nutrition position statement (2017), US RDA, American College of Sports Medicine guidelines.
Use cases
- Set a daily protein target. A 70 kg moderately-active adult: 1.2-1.6 g/kg = 84-112 g/day.
- Plan strength-training nutrition. 80 kg lifter aiming for muscle gain: 1.6-2.2 g/kg = 128-176 g/day.
- Senior nutrition planning. 65-year-old at 70 kg: 1.0-1.2 g/kg = 70-84 g/day to preserve lean mass.
- Spread protein across meals. 120 g / day across 4 meals = 30 g per meal — evidence-based for muscle protein synthesis.
How it works
- Enter body weight. kg or lb. Tool converts.
- Pick activity level. Sedentary, lightly active, moderately active, very active, athlete.
- Pick goal. Maintenance, muscle gain, fat loss while preserving muscle, elderly preservation.
- Read target. g/day range + per-meal split. Plus food examples (e.g. "1 chicken breast = 30g").
Examples
Input: 70 kg, moderately active, maintenance
Output: Target: 84-112 g/day. Per-meal (4 meals): 21-28 g.
Input: 80 kg, athlete, muscle gain
Output: Target: 128-176 g/day. Per-meal: 32-44 g (4 meals).
Input: 65 kg, elderly, preservation
Output: Target: 65-78 g/day. Higher per-meal for older muscle synthesis (~30 g threshold).
Frequently asked questions
Why does the range matter?
Individual variation. Lower end works for most; upper end for those genuinely active or in deficit. Don't exceed 2.5 g/kg without supervision.
Animal vs plant protein?
Both work. Plant protein typically needs ~10-20% more grams to compensate for lower digestibility and amino acid profile (per Phillips, 2012). Diversify plant sources.
Per-meal limits?
Muscle protein synthesis maximises around 25-40 g per meal in young adults; older adults may need 35-40 g to overcome anabolic resistance. Spreading across 3-5 meals beats one large dose.
Sources?
ISSN position 2017, NIH RDA, ACSM guidelines, Phillips 2012, Morton 2018 meta-analysis. Not medical advice — consult a registered dietitian.
Privacy?
All client-side.
Pro tips
- Spread protein across 3-5 meals — better for muscle protein synthesis than one large dose.
- Track for 2 weeks to know your actual intake — most people underestimate.
- For weight loss, increase to 1.6-2.2 g/kg (preserves muscle mass during deficit).
- Not medical advice — consult a registered dietitian for kidney issues, pregnancy, or specific medical conditions.
Reviewed by Ahsan Mahmood · Last updated 2026-05-06 · Part of ZTools.
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