Protein Calculator
Estimate daily protein needs from weight, activity, and goal. Includes BMR and TDEE, RDA by age, protein targets from 0.8 to 2.0 g/kg, per-meal splits, and calorie-share tables.
Calculator
Personal
Body Size
Energy & Formula
Protein Summary
Daily Protein Recommendations
| Recommendation | g/kg | Grams per Day | Share of TDEE |
|---|---|---|---|
| Minimum (RDA) | 0.8 | 64 g | 9.3% |
| Moderate | 1.2 | 95 g | 14.0% |
| Active | 1.6 | 127 g | 18.6% |
| Athlete | 1.8 | 143 g | 20.9% |
| Upper Limit | 2.0 | 159 g | 23.3% |
Protein as % of Total Calories
Based on TDEE of 2728 kcal/day. Protein provides 4 calories per gram. The recommended range is 10–35% of total calories.
| % of Calories | Protein Grams |
|---|---|
| 10% | 68 g |
| 15% | 102 g |
| 20% | 136 g |
| 25% | 171 g |
| 30% | 205 g |
| 35% | 239 g |
Recommended Dietary Allowance (RDA) by Age
| Age Group | RDA (g/day) |
|---|---|
| 1 - 3 years | 13 g |
| 4 - 8 years | 19 g |
| 9 - 13 years | 34 g |
| 14 - 18 years (Girls) | 46 g |
| 14 - 18 years (Boys) | 52 g |
| 19 - 70+ years (Women) | 46 g |
| 19 - 70+ years (Men) | 56 g |
Results
BMR
1760kcal/day
Mifflin-St Jeor basal metabolic rate
2728kcal/day
BMR × 1.55 (Moderate (moderate exercise 3-5 days/week))
56g/day
Institute of Medicine minimum by age and sex (0.8 g/kg baseline)
95–159g/day
Moderate to upper-limit for 79.4 kg body weight
143g/day
Strength and muscle-gain target within the 1.6–2.2 evidence range
42.3g/meal
Active 1.6 g/kg target split across three meals
31.8g/meal
Active 1.6 g/kg target split across four meals
159g/day
Practical ceiling for healthy adults; little added benefit above
BMR is an estimate accurate to about ±10–15% versus lab measurement, and activity factors average a whole week. The 1.6–2.2 g/kg evidence range covers most muscle-gain and dieting goals; treat 0.8 g/kg as the deficiency floor, not the target.
Visualizations
Daily Protein by Activity Level
Protein Calories at Active Target (1.6 g/kg)
Athlete Target vs Upper Limit (2.0 g/kg)
RDA Coverage
RDA vs Athlete Target
Formula
BMR prices the body at rest with Mifflin-St Jeor (weight, height, age, sex) or Katch-McArdle (lean mass only). TDEE scales BMR by activity (1.2–2.0). Protein then scales body weight by 0.8–2.0 g/kg, converts to calories at 4 kcal/g, and divides by TDEE for the calorie share.
Alternative Form
Variables
| Symbol | Name | Unit | Description |
|---|---|---|---|
| W | Body weight | kg | Total body mass; lb ÷ 2.20462 in US mode |
| H | Height | cm | Standing height; (ft×12 + in) × 2.54 in US mode |
| A | Age | yrs | Completed years, 18–80 in this calculator |
| BMR | Basal metabolic rate | kcal/day | Mifflin-St Jeor or Katch-McArdle resting burn |
| k | Activity factor | ratio | 1.2 sedentary through 2.0 extra active |
| TDEE | Total daily energy expenditure | kcal/day | BMR × k; denominator for calorie shares |
| f | Protein factor | g/kg | 0.8 RDA · 1.2 moderate · 1.6 active · 1.8 athlete · 2.0 upper |
Explanation
Weight sets the protein price per kilogram, BMR and activity set the calorie budget, and the factor sets the goal. A 79 kg adult at 1.6 g/kg needs ~127 g (508 kcal); against a 2,728 kcal TDEE that is ~19% of calories — inside the 10–35% AMDR band.
Derivation
At 79.4 kg, 177.8 cm, 30 y male, moderate 1.55: BMR = 10×79.4 + 6.25×177.8 − 5×30 + 5 = 1,760. TDEE = 1,760 × 1.55 = 2,728. Protein 1.6 × 79.4 = 127 g = 508 kcal = 18.6% of TDEE. RDA = 56 g (0.7 g/kg at this size).
Step-by-Step Calculation
Follow each step to understand how the result is calculated from your inputs.
Convert body weight to kilograms for the gram-per-kilogram targets.
Convert height to centimetres and estimate BMR with the selected formula.
Multiply BMR by the activity factor to get total daily energy expenditure.
Apply each protein factor to body weight in kilograms.
Look up the RDA minimum for age and sex and compare it with the active target.
Express protein as calories (4 kcal/g) and as a share of TDEE, then split across meals.
Worked Examples
See how the calculator works with different scenarios.
Scenario
A 30-year-old man, 5'10" (178 cm), 175 lb, moderate exercise 3–5 days/week, Mifflin-St Jeor.
Inputs
Calculation
W = 175 ÷ 2.20462 = 79.4 kg BMR = 10×79.4 + 6.25×177.8 − 5×30 + 5 = 1,760 TDEE = 1,760 × 1.55 = 2,728 Protein 1.6 × 79.4 = 127 g
Result
BMR 1,760 · TDEE 2,728 kcal · RDA 56 g · Recommended 95–159 g · Athlete 143 g · 42.3 g × 3 meals
Interpretation
The classic baseline: RDA covers deficiency at 64 g, but the active 127 g target (~19% of TDEE) supports training and fullness. Three 42 g meals hit it with standard meat, dairy, and legume portions.
Understanding Your Result
Your Result: BMR: 1760 kcal/day
Typical range: RDA 0.8 g/kg is the floor. Moderate 1.2, active 1.6, athlete 1.8, upper 2.0 g/kg. Evidence clusters at 1.6–2.2 for growth and 1.6–2.4 in deficits. AMDR protein share is 10–35% of TDEE; 20–40 g per meal maximises synthesis.
What This Means
Every figure is your body translated into protein: the BMR and TDEE calorie budget, the RDA floor by age and sex, the 1.2–2.0 g/kg working range for your exact kilograms, the 1.8 athlete point, and that range split into 3- and 4-meal servings.
Why It Matters
The RDA prevents deficiency; it does not optimise training, dieting, or ageing. A 79 kg adult at RDA eats 64 g, but needs ~127 g to support sessions and ~150 g to diet without losing muscle — the calculator shows both numbers side by side so the gap is actionable.
Professional Interpretation
Counsel from TDEE down: confirm the BMR method (Katch when body fat is known), set the factor by goal and phase, then back-solve meals. Flag renal disease, pregnancy, and masters athletes for individualised targets rather than the default band.
Recommendations
- •Anchor on 1.6 g/kg, adjust to 1.2 when sedentary or 1.8–2.0 when dieting or growing
- •Serve 20–40 g per meal across 3–4 meals with 2–3 g leucine each
- •Put protein with carbohydrate around training for recovery
- •Recheck after any 5 kg weight change or activity shift
- •Seniors: favour the top half of the range plus resistance work
Educational Content
Introduction
The Protein Calculator converts body weight into daily grams using evidence-based factors, then frames those grams with the calorie budget (BMR × activity), the Institute of Medicine RDA floor, per-meal servings, and the share of TDEE — so one screen serves lifters, dieters, and older adults alike.
Concept Explanation
Protein need scales with kilograms, not calories. BMR (Mifflin-St Jeor or Katch-McArdle) times activity gives TDEE; factor (0.8–2.0) times kilograms gives grams; grams times 4 divided by TDEE gives the calorie share checked against the 10–35% AMDR.
Applications
Benefits
- •Weight-based grams replace generic percentage guesses
- •BMR plus TDEE keeps protein inside the real calorie budget
- •RDA table exposes when the minimum is not enough
- •Per-meal splits turn daily totals into plates
- •Calorie-share table links grams to the 10–35% band
Limitations
- •BMR equations estimate rest burn within about ±10–15%
- •Factors are population averages, not metabolic-chamber results
- •Single weight point ignores composition shifts over time
- •Clinical cases (renal, pregnancy, illness) need individual care
Best Practices
- •Use Katch-McArdle whenever body-fat percentage is known
- •Weigh under consistent conditions and re-run after 5 kg shifts
- •Distribute protein evenly rather than back-loading dinner
- •Prioritise complete proteins or complementary plant pairs
- •Pair higher targets with fibre, water, and resistance training
Common Misconceptions
Practical Tips
- •Anchor sedentary days at 1.2 and training blocks at 1.6–1.8 g/kg
- •Build each meal around 20–40 g with a leucine-rich anchor
- •Log body weight weekly and re-run after 5 kg changes
- •Use Katch-McArdle when you know body-fat percentage
- •Pair shakes with meals, not instead of them, outside travel days
- •Front-load protein at breakfast to cut evening cravings
- •Seniors: keep 25–35 g per meal plus twice-weekly lifting
Common Mistakes
Assumptions
This calculator makes the following assumptions to provide estimates:
Limitations
Be aware of these limitations when using this calculator:
Frequently Asked Questions
Answers to common questions about this calculator.
How much protein do I need per day?
What is the RDA for protein?
How much protein do I need for muscle gain?
How much protein do I need for weight loss?
Can you eat too much protein?
Is a high-protein diet safe for kidneys?
What are the best sources of protein?
Is plant protein as good as animal protein?
What is a complete protein?
What are essential amino acids?
What is the difference between whey and casein protein?
When should I take protein?
Do I need protein powder to meet my protein needs?
Should I eat protein before or after a workout?
How much protein should I eat per meal?
Is there a limit to how much protein the body can absorb per meal?
Do protein needs change as we age?
How can vegetarians meet their protein needs?
How can vegans meet their protein needs?
Does protein help with hair growth?
How does protein support immune function?
What is the relationship between protein and bone health?
How does protein increase satiety?
What is the thermic effect of protein?
How much protein do I need during pregnancy?
What are the protein needs for athletes?
Do protein needs differ for endurance vs. strength athletes?
What is the difference between BCAAs and protein?
Can protein help with exercise recovery?
Are protein shakes better than whole food protein sources?
How do I calculate protein from food labels?
What is the Acceptable Macronutrient Distribution Range (AMDR) for protein?
Is it possible to get too much protein from whole foods?
How does the Mifflin-St Jeor equation work here?
When should I use Katch-McArdle instead?
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Related Guides
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Glossary
Technical terms used in mortgage calculations explained in plain language.
- RDA
- Recommended Dietary Allowance: 0.8 g/kg/day minimum against deficiency; 46 g (women) / 56 g (men) at reference sizes.
- BMR
- Basal metabolic rate: resting calorie burn from Mifflin-St Jeor or Katch-McArdle.
- TDEE
- Total daily energy expenditure: BMR × activity factor (1.2–2.0).
- g/kg
- Grams of protein per kilogram of body weight — the unit of every target here.
- Lean mass
- (1 − bodyFat/100) × weight; the tissue Katch-McArdle prices at 21.6 kcal/kg plus 370.
- AMDR
- Acceptable Macronutrient Distribution Range: 10–35% of calories from protein.
- Leucine threshold
- ~2–3 g leucine per meal to maximally trigger muscle protein synthesis.
- Complete protein
- Food with all nine essential amino acids in adequate amounts.
- Thermic effect
- Digestion cost: ~20–30% for protein vs 5–10% carbs and 0–3% fat.
- Anabolic resistance
- Blunted muscle-building response with ageing; why seniors need 1.2–2.0 g/kg.
Authoritative References
Trusted sources and standards referenced by this calculator.
Applicable Standards
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Page Information
2026-08-07
2.0.0
- Institute of Medicine — Dietary Reference Intakes for Protein (RDA 0.8 g/kg; AMDR 10–35%)
- ISSN Position Stand — Protein and Exercise (JISSN 2017)
- USDA MyPlate — Protein Foods
- NIH Office of Dietary Supplements — Protein Fact Sheet
- Examine.com — Protein Intake Guide
- Academy of Nutrition and Dietetics — Protein Guidance
- Morton et al. — Protein Timing and Hypertrophy (PubMed)
- Precision Nutrition — Protein Guide
Free to use for educational and professional purposes.