Macronutrient Calculator
Calculate the right protein, carbs and fat for your body and goal. Uses the Mifflin-St Jeor equation for BMR, multiplies by activity for TDEE, then splits calories by an evidence-based ratio for your chosen goal.
How to use this calculator
- Pick your goal at the top — Daily Macros for general use, then Weight Loss, Muscle Gain or Keto.
- Enter your stats — gender, age, weight and height. Switch units if you prefer pounds and inches.
- Choose activity honestly. Overestimating is the single most common reason people don't see results.
- Pick the deficit, surplus or carb limit that matches the aggressiveness you want.
- The result panel updates live. Track your intake against these numbers in any food-logging app and review weekly.
Real-world examples
Sarah — sustainable weight loss
35-year-old female · 170 lb · 5'5" · gym 3×/week
| Daily calories | ≈ 1,550 kcal (500 kcal deficit) |
|---|---|
| Protein | 170 g · 1 g per lb of bodyweight |
| Carbs | 116 g · 30% of calories |
| Fat | 52 g · 30% of calories |
Mike — lean muscle gain
25-year-old male · 165 lb · 5'11" · lifts 5×/week
| Daily calories | ≈ 2,850 kcal (+350 kcal surplus) |
|---|---|
| Protein | 165 g · 1 g per lb |
| Carbs | 356 g · 50% of calories |
| Fat | 79 g · 25% of calories |
Lisa — strict keto
42-year-old female · 180 lb · 5'6" · light activity
| Daily calories | ≈ 1,450 kcal |
|---|---|
| Fat | 113 g · 70% of calories |
| Protein | 90 g · 0.5 g per lb |
| Net carbs | 20 g · strict keto cap |
Macro split reference
Recommended ratios by goal. These are starting points — adjust by 5% in either direction based on real-world results after 2–3 weeks.
| Goal | Protein | Carbs | Fat | Notes |
|---|---|---|---|---|
| Maintenance | 25–30% | 40–50% | 25–30% | Balanced approach |
| Weight loss | 35–40% | 25–35% | 25–30% | Higher protein preserves muscle |
| Muscle gain | 25–30% | 45–55% | 20–25% | Carbs fuel hard training |
| Keto | 20–25% | 5–10% | 70–75% | Very low carb, fat-dominant |
| Low carb | 30–35% | 15–25% | 40–50% | Moderate restriction |
Calories per gram
| Macro | Calories / g | Primary function |
|---|---|---|
| Protein | 4 | Muscle repair, satiety, thermic effect |
| Carbohydrate | 4 | Energy, brain function, exercise fuel |
| Fat | 9 | Hormones, vitamin absorption, satiety |
| Alcohol | 7 | No nutritional value |
Fat is more than twice as calorie-dense as protein or carbs — that is why a tablespoon of olive oil or peanut butter has such an outsized impact on your daily total.
Tips for hitting your macros
Prioritise protein
Plan protein first at every meal. It is the hardest macro to hit and the most important for body composition.
Track everything
Use MyFitnessPal, Cronometer or MacroFactor. Weigh food on a scale — eyeballing is off by 20–50%.
Meal-prep
Prepare 2–3 days at a time. Hitting macros is far easier when you control the ingredients.
Aim for ±5 g
You don't need to be exact. Within five grams of each macro is close enough to drive the same outcome.
Adjust over time
Recalculate every 10–15 lb gained or lost. Your needs change as your body changes.
Don't forget water
Hydration influences performance and hunger. Aim for half your bodyweight in ounces daily.
Understanding macronutrients
Macronutrients are the three nutrients your body needs in large amounts: protein, carbohydrate and fat. Together they account for 100% of your dietary energy. Micronutrients — vitamins and minerals — are required only in milligram or microgram quantities.
Protein — the building block
Protein is built from 20 amino acids, nine of which your body cannot produce. Adequate protein supports muscle protein synthesis after training, drives the immune system through antibody production, makes most of your enzymes and is by far the most satiating macro. Roughly 20–30% of protein calories are burned in digestion (the thermic effect of food) — for carbs it's 5–10% and for fat just 0–3%.
For most active people, 0.7–1.0 g per pound of bodyweight per day is the practical target. During an aggressive cut, push toward 1.0–1.2 g per pound to better preserve lean mass.
Carbohydrates — your primary fuel
Carbs break down to glucose, which fuels your brain and powers high-intensity exercise. Excess glucose is stored as muscle and liver glycogen. Three useful sub-categories:
- Simple carbs — sugars in fruit, honey and processed food. Rapidly absorbed.
- Complex carbs — starches and fibre in whole grains, legumes and vegetables. Slower release, steadier energy.
- Fibre — indigestible carbohydrate. Vital for gut health, satiety and blood-sugar control. Most adults should target 25–38 g/day.
Fat — essential, not the enemy
Dietary fat was unfairly demonised for decades. It is essential for hormone production (testosterone, oestrogen), absorption of fat-soluble vitamins (A, D, E, K) and structural integrity of every cell membrane.
- Monounsaturated — olive oil, avocados, most nuts. Heart-healthy.
- Polyunsaturated — omega-3 and -6, found in oily fish, flaxseed, walnuts. Anti-inflammatory.
- Saturated — meat, dairy, coconut oil. Moderate intake is fine for most people.
- Trans fats — industrially produced. Avoid entirely.
Most guidelines recommend 20–35% of calories from fat. Going below 20% for long stretches risks hormonal disruption.
How the Mifflin-St Jeor equation works
This calculator uses Mifflin-St Jeor — the most accurate BMR formula for healthy adults, validated across hundreds of studies since its publication in 1990 and within ±10% for most people.
The formula
Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
BMR is then multiplied by an activity factor to get TDEE — your Total Daily Energy Expenditure.
Worked example
30-year-old male, 170 lb (77.1 kg), 5'10" (177.8 cm), moderately active, maintaining weight:
- BMR = (10 × 77.1) + (6.25 × 177.8) − (5 × 30) + 5 = 1,737 kcal
- TDEE = 1,737 × 1.55 = 2,692 kcal
- Maintenance split (30 / 40 / 30): Protein 202 g · Carbs 269 g · Fat 90 g
Activity-level guide
Pick honestly. The most common error in macro calculation is overestimating activity — when in doubt, drop one tier. You can always add food later.
| Level | × | Description | Steps / day |
|---|---|---|---|
| Sedentary | 1.2 | Desk job, no exercise | < 5,000 |
| Lightly active | 1.375 | Light exercise 1–2 days / week, walks, yoga | 5,000–7,500 |
| Moderately active | 1.55 | Gym 3–5 days, recreational sport, active job | 7,500–10,000 |
| Active | 1.725 | Hard training 6–7 days, weights + cardio, manual job | 10,000–12,500 |
| Very active | 1.9 | Two-a-day training, military boot camp, athlete | 12,500+ |
Weekly calorie targets
Looking at the week rather than the day gives you flexibility — a higher day can be offset by a lower one. Projections assume consistent adherence; weight loss is rarely linear in week-to-week reality.
| Goal | Daily adjustment | Weekly | Weekly change | Monthly |
|---|---|---|---|---|
| Aggressive fat loss | −750 kcal | −5,250 kcal | ~1.5 lb lost | ~6 lb |
| Moderate fat loss | −500 kcal | −3,500 kcal | ~1.0 lb lost | ~4 lb |
| Slow fat loss | −250 kcal | −1,750 kcal | ~0.5 lb lost | ~2 lb |
| Maintenance | 0 | 0 | No change | — |
| Lean bulk | +200 kcal | +1,400 kcal | ~0.4 lb gained | ~1.5 lb |
| Moderate bulk | +350 kcal | +2,450 kcal | ~0.7 lb gained | ~3 lb |
| Aggressive bulk | +500 kcal | +3,500 kcal | ~1.0 lb gained | ~4 lb |
Macro counting vs other approaches
| Factor | Macro counting | Calorie counting | Keto | Intuitive eating |
|---|---|---|---|---|
| Precision | High — all 3 macros | Moderate — total only | Moderate — carb-focused | Low — no tracking |
| Flexibility | High — any food fits | High | Low — many foods restricted | High |
| Learning curve | Moderate | Low | Moderate | Low |
| Body composition | Excellent | Good (may lose muscle) | Good (initial water loss) | Variable |
| Sustainability | Moderate — tracking effort | Moderate | Low long-term | High |
| Best for | Athletes, optimisers | General weight management | Therapeutic, rapid initial loss | History of disordered eating |
High-protein foods reference
Hitting protein is usually the hardest part. Memorise a few of these as reliable building blocks.
| Food | Serving | Protein | Calories |
|---|---|---|---|
| Chicken breast (skinless) | 6 oz / 170 g | 54 g | 280 |
| Greek yogurt (non-fat) | 1 cup / 245 g | 22 g | 130 |
| Egg whites | 1 cup / 243 g | 26 g | 126 |
| Salmon (Atlantic) | 6 oz / 170 g | 40 g | 350 |
| Lean ground turkey (93%) | 6 oz / 170 g | 48 g | 320 |
| Cottage cheese (1%) | 1 cup / 226 g | 28 g | 160 |
| Whey protein isolate | 1 scoop / 30 g | 25 g | 110 |
| Canned tuna (in water) | 1 can / 142 g | 33 g | 140 |
| Shrimp | 6 oz / 170 g | 36 g | 170 |
| Tofu (extra firm) | ½ block / 200 g | 22 g | 180 |
| Lentils (cooked) | 1 cup / 198 g | 18 g | 230 |
| Sirloin steak | 6 oz / 170 g | 46 g | 340 |
Protein sources by quality
Bioavailability matters. The Digestible Indispensable Amino Acid Score (DIAAS) is the FAO's recommended measure of protein quality — higher scores mean your body absorbs and uses more of what you eat. Plant proteins generally score lower; combining them strategically (rice + beans, hummus + bread) raises overall quality to near-animal levels.
| Source | Protein / serving | DIAAS | Bioavailability | Complete? |
|---|---|---|---|---|
| Whey isolate | 25 g / scoop | 1.09 | ~99% | Yes |
| Whole eggs | 6 g / egg | 1.13 | ~98% | Yes |
| Chicken breast | 31 g / 100 g | 1.08 | ~97% | Yes |
| Whole milk | 8 g / cup | 1.14 | ~95% | Yes |
| Lean beef | 26 g / 100 g | 1.10 | ~94% | Yes |
| Cod | 23 g / 100 g | 1.05 | ~93% | Yes |
| Soy isolate | 22 g / scoop | 0.90 | ~91% | Yes |
| Quinoa | 8 g / cup cooked | 0.84 | ~83% | Yes |
| Chickpeas | 15 g / cup cooked | 0.83 | ~78% | No (low methionine) |
| Pea protein | 21 g / scoop | 0.82 | ~80% | No (low methionine) |
| Brown rice | 5 g / cup cooked | 0.60 | ~73% | No (low lysine) |
| Wheat gluten | 23 g / 100 g | 0.40 | ~64% | No (low lysine) |
Common mistakes when tracking macros
Not weighing food
Cups and eyeballs are off by 20–50%. A $15 kitchen scale is the single best investment in accurate tracking. A "tablespoon" of peanut butter is often double when scooped casually.
Ignoring oils and sauces
One tablespoon of olive oil is 120 kcal and 14 g of fat. Marinades, dressings and cooking sprays add 200–400 hidden kcal/day. Always log what you cook with.
Overestimating activity
A 30-minute gym session 3×/week with a desk job is "Lightly active", not "Moderate". Be brutally honest.
Not adjusting over time
As you lose weight, TDEE drops. Someone who loses 20 lb usually needs 150–200 fewer kcal/day. Recalculate every 10–15 lb or 6–8 weeks.
Macros over food quality
Hitting macros with only processed food leaves you nutrient-deficient. Aim for ~80% whole foods (lean meats, vegetables, whole grains, fruits) and 20% flexible.
Weekend overcompensation
Tracking Mon–Fri then a 3,000 kcal Saturday can erase the entire week's deficit in a single day.
Skipping protein at breakfast
A carb-heavy breakfast (cereal, toast, juice) leaves protein impossible to hit later. Front-load with eggs, yogurt or a shake.
Not tracking beverages
Lattes, smoothies, alcohol and "healthy" juices add up fast. A large Frappuccino is 60–80 g of carbs and 400+ kcal.
When to recalculate
- Every 10–15 lb of body-weight change — even a 10 lb shift moves your BMR by 50–70 kcal/day.
- After a 3-week plateau — if the scale hasn't moved while you've been consistent, drop carbs or fat slightly (not protein).
- When activity changes meaningfully — new job, new training programme, new sport.
- Every 6–8 weeks anyway — to compensate for metabolic adaptation.
- When switching goals — cut → bulk or vice versa needs a full reset, not a guess.
- After illness, injury or pregnancy — work with a healthcare provider and run the numbers fresh.
Frequently asked questions
What are macros?
Macros (macronutrients) are the three nutrients that supply calories: protein, carbohydrate and fat. You need them in gram quantities every day. See counting macros for beginners.
How accurate is this calculator?
It uses Mifflin-St Jeor, which is within ±10% for most healthy adults. Use the output as a starting point, then adjust after 2–3 weeks based on real-world results.
Should I count net carbs or total carbs?
For keto, count net carbs (total − fibre). For general macro tracking, either works — just be consistent.
How much protein do I really need?
0.7–1.0 g per pound of bodyweight for active people. Push to 1.0–1.2 g/lb during a cut to preserve muscle. Above 1.2 g/lb rarely adds benefit. See protein intake guide.
What's the best macro split for weight loss?
40 / 30 / 30 (P / C / F) is the standard. Higher protein preserves muscle and increases satiety. Calorie deficit is still the biggest lever. Read macros for weight loss.
Do I have to hit my macros exactly?
No. Within 5–10 g of each is plenty. Consistency over weeks beats daily perfection.
Should I eat back exercise calories?
Generally no — exercise tracker estimates are typically 30–50% inflated, and your activity multiplier already accounts for normal training. Only consider it for unusually long sessions (2 h+).
What's IIFYM?
"If It Fits Your Macros" — flexible dieting where any food is fair game as long as totals are met. It works best when 80%+ of food is nutritious.
BMR vs TDEE — what's the difference?
BMR is what you'd burn lying in bed all day. TDEE is BMR × an activity factor — what you actually burn including movement and exercise. Macros are based on TDEE, not BMR. Don't eat below your BMR for extended periods.
Can I build muscle and lose fat at the same time?
Yes — it's called body recomposition. Best results for beginners, returners and people with higher body fat. Eat at maintenance (or a tiny deficit), 1 g/lb protein, train hard. Progress is slower but visible.
What about restaurant meals?
Check chain nutrition info beforehand, choose simple grilled dishes, estimate portions visually (palm = ~4 oz protein), overestimate slightly (restaurants use more oil), and treat eating out as part of your 20% flexible allowance.
Is macro counting safe for everyone?
Generally yes for healthy adults. Not recommended for anyone with a history of disordered eating, children, or pregnant/breastfeeding women without medical guidance.
Why am I not losing weight even though I'm hitting my macros?
Verify scale weighing accuracy, log every drink and condiment, drop your activity tier, recalculate using current bodyweight, and look at non-scale wins (measurements, strength). If still stuck after 4 weeks, drop calories ~10%.
Are macros different for women?
The formula is the same, but women generally have lower BMR, slightly lower protein needs per pound (0.7–0.9 g/lb) and should not drop fat below 20% of calories — it can disrupt hormones and the menstrual cycle.
Can I drink alcohol while tracking?
Yes, but it's hard. Alcohol is 7 kcal/g with no nutritional value. Most trackers count it against carbs or fat. It also impairs muscle protein synthesis and lowers food-choice inhibitions. Limit to 1–2 drinks and choose lower-calorie options.
Related guides
Educational estimate only. For medical or competitive athletic programming consult a registered dietitian.