Free Protein Calculator
See Exactly How Your Number Is Calculated
Enter your stats below. The calculator shows your daily protein target and the complete step-by-step calculation behind it.
Protein Calculator
Calculate your target
How This Protein Calculator Works
This calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate: the calories your body burns at complete rest. It then applies an activity multiplier to estimate Total Daily Energy Expenditure, and adjusts calories based on your selected goal and weekly pace.
The protein target is set using evidence-backed protein ranges: 1.6 to 2.2 grams per kilogram of body weight per day, with the multiplier adjusted by goal, activity, and deficit size.
The result is not a fixed prescription. It is a starting point. Most people need two to four weeks of tracking to calibrate the estimate to real body-weight trends and appetite.
Why Different Calculators Give Different Results
Three BMR formulas are in common use. Here is how they compare for the same person: 75kg, 175cm, 30 years, male, moderately active.
| Formula | BMR Result | TDEE (x1.55) | Best For | This Calculator |
|---|---|---|---|---|
| Mifflin-St Jeor ★ | 1,674 kcal | 2,595 kcal | General population | Used here |
| Harris-Benedict revised | 1,752 kcal | 2,716 kcal | Older research baseline | - |
| Katch-McArdle | Varies by body fat | Varies | Known body fat % | - |
Mifflin-St Jeor is widely used for the general population. Katch-McArdle can be more useful when body fat percentage is known, but that requires better body composition data. Formula differences of 5-10% are normal.
Understanding Your Protein Calculator Results
Your results panel shows the numbers that matter most. Here is what each one means and how to use it in practice.
Daily Protein Target
The total grams of protein you need every day to preserve muscle while losing fat.
This is your non-negotiable daily number. Track protein explicitly, not just calories. Most people who struggle to preserve muscle during fat loss are hitting calories but missing protein.
Per-Meal Protein Target
The minimum protein per meal needed to make each sitting useful.
Distribute protein across three to four meals where possible. A meal below roughly 25-30g protein is less useful for muscle protein synthesis because the leucine threshold may not be cleared.
Daily Calorie Target
Your estimated maintenance calories adjusted by your chosen goal pace.
Treat this as a weekly average, not a fragile daily ceiling. One day slightly above target does not matter. A full week above target does.
Weekly Fat Loss Estimate
The expected scale trend from your selected calorie deficit.
Expect water, glycogen, and digestive content to hide fat loss from day to day. Judge progress over three to four week averages, not individual weigh-ins.
Protein Multiplier Used
The grams-per-kilogram ratio applied to body weight.
If the target is hard to hit, use the lower end of the range. If you train hard in a deficit and want maximum lean-mass retention, stay closer to the upper end.
Protein Calorie Share
How much of your calorie budget is taken by protein.
This helps you check whether the target still leaves enough room for carbs and fats. If the percentage gets very high, use leaner foods and a realistic meal structure.
What to Do With Your Protein Target
A number without a plan is just a number. Use this three-step sequence to turn your calculator result into daily action.
Know What 30-50g of Protein Looks Like
Your daily target is a number, but you need to know what that number looks like on a plate. The most common reason people miss their protein target is lack of calibration. Start by learning the protein content of the five to eight foods you eat most often.
See protein content of 40+ foodsBuild a Meal Structure That Hits the Target
Knowing your daily target is not enough. You need a meal structure that reliably delivers it. Most people naturally land at 60-80% of their target, with the gap usually at breakfast and snacks.
See the 7-day high protein meal planOptimise Timing Around Your Schedule
Once you are consistently hitting the daily target, timing becomes the next optimisation layer. Use morning protein, workout protein, and a planned evening serving to make the number easier to repeat.
Build your protein timing scheduleHow Accurate Is This Protein Calculator?
All BMR calculators are estimates. The Mifflin-St Jeor equation has a typical individual error range of roughly 10%, meaning a calculated calorie result can be meaningfully higher or lower than measured energy expenditure.
Protein targets are more stable because they are based on body weight rather than predicted metabolism. The 1.6-2.2g/kg range is appropriate for the vast majority of people pursuing fat loss, maintenance, or muscle gain with resistance training.
Protein Targets by Goal
The calculator adjusts your protein target based on your goal. Here is the reference for all three scenarios.
Fat Loss
1.8-2.2g / kg
Higher end of the ISSN range. A calorie deficit increases muscle breakdown risk, so a higher protein intake supports lean-mass retention and satiety.
Anyone in a 300-700 kcal/day deficit trying to lose fat while preserving as much muscle as possible.
If the deficit is very large, use the upper end of the range.
See protein and calorie deficit guideMaintenance / Recomposition
1.6-2.0g / kg
Standard ISSN recommendation for active adults. At maintenance, muscle breakdown risk is lower. For recomposition, use the upper end.
People near goal weight who want to maintain body composition or pursue slow recomposition.
Use 2.0g/kg when training hard at maintenance calories.
See body recomposition protein guideMuscle Building
1.6-2.2g / kg
Muscle protein synthesis research shows diminishing returns above roughly 1.6g/kg during a surplus. Advanced lifters may still prefer the upper end.
People in a 200-500 kcal/day surplus using progressive resistance training to build lean mass.
The main difference from fat loss is calories, not protein.
See protein calculator for cuttingMen's Fat Loss
1.8-2.5g / kg
Male fat loss has a dual target: maintain enough deficit to reduce visceral fat while keeping protein high enough to protect muscle as testosterone changes with age.
Men cutting body fat while trying to preserve strength, muscle size, and training performance.
Use the dedicated men's calculator for age-stage, body-type, and training-experience adjustments.
See men's weight-loss calculatorFrequently Asked Questions
Is this protein calculator really free?+
Yes. It is completely free, with no signup, no email, and no paywall. The calculator runs in your browser and uses the Mifflin-St Jeor formula plus evidence-backed protein guidelines.
How accurate is the protein calculator?+
The Mifflin-St Jeor equation predicts BMR within about 10% for many adults. Protein targets are based on body weight and the 1.6-2.2g/kg evidence-backed range. Use the calculator as a starting point and adjust after three to four weeks of tracked results.
How much protein do I need per day?+
The evidence-backed range for active adults pursuing fat loss is 1.6 to 2.2 grams per kilogram of body weight per day. For a 75kg person, that is 120 to 165 grams per day. The exact target depends on goal, activity, and deficit size.
What formula does this calculator use?+
The calculator uses the Mifflin-St Jeor equation for BMR, an activity multiplier for TDEE, a calorie adjustment based on goal pace, and protein guidelines in the 1.6-2.2g/kg range. The transparency panel shows every step.
Should I use current weight or goal weight?+
Use your current body weight. Protein targets are set relative to the body you are feeding now, not the body weight you plan to reach later. Recalculate every four to six weeks as weight changes.
Why is my result different from other calculators?+
Different calculators use different BMR formulas, activity multipliers, and protein ranges. Reputable calculators usually differ by 5-15%, which is within the normal range of individual metabolic variation.
Ready to Go Beyond the Number?
You have your protein target. Now use the resources below to turn it into a daily plan: meal structure, food choices, and timing strategy.