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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​

  1. Enter body weight — kg or lb. Tool converts.
  2. Pick activity level — Sedentary, lightly active, moderately active, very active, athlete.
  3. Pick goal — Maintenance, muscle gain, fat loss while preserving muscle, elderly preservation.
  4. 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.

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.

Try it now​

The full protein-intake-calculator runs in your browser at https://ztools.zaions.com/protein-intake-calculator — no signup, no upload, no data leaves your device.

Open the tool ↗

Last updated: 2026-05-06 · Author: Ahsan Mahmood · Edit this page on GitHub