Free Macro Calculator for Fat Loss
Calculate Your Personalised Macros
Find out exactly how much protein, carbs, and fat you need to hit your goals. Takes 30 seconds.
How this macro calculator works
First it works out your calories. It estimates your basal metabolic rate (BMR) with the Mifflin-St Jeor equation, then multiplies it by your activity level to get your maintenance calories: 1.2 for sedentary, 1.375 for light, 1.55 for moderate, 1.725 for very active and 1.9 for extra active.
Then it adjusts for your goal. Lose Body Fat sets your calories 20% below maintenance, and never below 1,500 kcal for men or 1,200 kcal for women. Build Lean Muscle adds 7%, and Bulk adds 17%.
Then it splits those calories, protein first, fat second, carbs from what's left:
- Protein comes from your estimated lean mass (the Boer formula), not your total weight. For fat loss that's 2.55 g per kg of lean mass for men and 2.25 g for women.
- Fat is a share of your calories: 27.5% for men losing fat or building lean muscle, 32.5% for women and for anyone bulking.
- Carbs fill the rest of your calories.
- Nothing goes below 50 g of protein, 30 g of fat or 50 g of carbs a day.
What are macros?
Macros, short for macronutrients, are the three nutrients that give you energy: protein, carbohydrate and fat.
- Protein (4 kcal per gram) builds and repairs muscle and keeps you full. It's the one to protect in a deficit.
- Carbohydrate (4 kcal per gram) fuels training and your brain, and refills the glycogen in your muscles.
- Fat (9 kcal per gram) supports hormones, helps you absorb some vitamins and makes food taste good.
- Alcohol isn't a macro, but it still counts at 7 kcal per gram, which matters for business dinners.
How to set your macros for fat loss
- Set your calories. Our calorie deficit calculator gives you maintenance, a safe fat loss target and an estimated weekly loss.
- Set protein at about 1.6–2.2 g per kg of bodyweight. This calculator works from lean mass instead, which lands inside that range for most men.
- Set fat at about 0.6–1.0 g per kg of bodyweight. Don't go much lower for long: very low fat tends to hurt energy, mood and hormones.
- Fill the rest with carbs, and put most of them around your training.
Worked example
Take a 40-year-old man, 180 cm and 95 kg, lightly active, who picks Lose Body Fat. His maintenance is about 2,585 kcal, so his target is about 2,068 kcal a day. Here's how the calculator splits it:
| Macro | Grams | Calories | Share |
|---|---|---|---|
| Protein | 172 g | 688 kcal | 33% |
| Carbs | 203 g | 812 kcal | 39% |
| Fat | 63 g | 567 kcal | 28% |
| Total | 2,067 kcal | 100% |
The total is 1 kcal off the 2,068 target only because the grams are rounded. His protein works out at about 1.8 g per kg of bodyweight and his fat at about 0.66 g per kg, both inside the ranges above.
How to calculate calories from macros
Multiply each macro by its energy value and add them up: calories = protein (g) × 4 + carbs (g) × 4 + fat (g) × 9.
For example, 150 g of protein, 200 g of carbs and 60 g of fat is 150 × 4 + 200 × 4 + 60 × 9 = 600 + 800 + 540 = 1,940 kcal.
Australian food labels list energy in kilojoules. To turn kilojoules into calories, divide by 4.184: a 1,000 kJ snack is about 240 kcal.
The best macro ratio for cutting
Grams per kilogram beat fixed percentages. A 30% protein split gives a big man on high calories far more protein than he needs, and a smaller woman on low calories too little. Setting protein and fat from your body, then letting carbs move with your calories, keeps the important numbers right whatever your size.
If you do want ratios, most cutting diets land around 30–40% protein, 25–35% fat and the rest carbs. The worked example above comes out at about 33% protein, 39% carbs and 28% fat.
You can also shift carbs towards training days: a bit more on the days you lift, a bit less on rest days, with the weekly total the same.
Macros for men over 35
After 35, holding on to muscle takes more deliberate effort, so protein matters more, not less. Spread it across three or four meals so every meal does some of the work for recovery.
Sleep and stress change how hungry you are and how well you train. When work is flat out, keep protein and calories steady and let the rest slide rather than cutting harder.
Work functions are part of the job. Count the drinks: a glass of wine is roughly 120 kcal and a schooner of full-strength beer about 170 kcal, and most of that should come out of your fat and carbs for the day, not your protein.
Tracking your macros
Enter these numbers as your daily goals in MyFitnessPal or any tracking app, then log what you eat. Weigh the foods you eat most for the first couple of weeks so you learn what a portion really looks like.
In a busy week, simplify: hit your protein and your calories, and don't worry if carbs and fat are a little off. That's enough to keep fat loss moving.
Macro calculator FAQs
How accurate is this macro calculator?
It's a solid starting point, not a lab test. The Mifflin-St Jeor equation is one of the most reliable ways to estimate calories without equipment, but individual people can sit a few hundred calories either side. Follow your numbers for two to three weeks, watch your weekly average weight, and adjust by 100–200 kcal if the trend isn't heading where you want.
How often should I recalculate my macros?
Every 4–5 kg of weight lost, whenever your activity changes a lot (a new job, a new training program), or when your weekly average has stalled for three weeks. As you get lighter, your maintenance calories drop, so the same numbers slowly stop working.
Should I eat back exercise calories?
Usually not. The activity level you chose is already in your calories, so adding back what a watch says you burned counts the same exercise twice. Fitness trackers also tend to overestimate. After an unusually big session, like a long ride or a half marathon, a little extra food is fine.
Is this better than the MyFitnessPal macro calculator?
They do different jobs. This calculator sets protein from your estimated lean mass and fat as a share of calories, which suits fat loss without losing muscle. MyFitnessPal is a good place to log your food. Use this calculator to set the targets, then enter them as your goals in MyFitnessPal or whichever app you prefer.
Do I need to hit my macros exactly every day?
No. Aim to land within about 5–10 grams on protein and keep your calories close, and let carbs and fat move around. What matters is your weekly average. One day over is fine as long as most days are close.
What if I'm not losing weight?
First check your tracking: weekend meals, drinks, cooking oils and sauces are the usual gaps. If your logging is honest and your weekly average hasn't moved in three weeks, drop your calories by 100–200 kcal, mostly from carbs and fat, and keep protein where it is.
Related
Not sure how many calories to start from? The calorie deficit calculator gives you a fat loss target with safe floors. If you want a coach to adjust your numbers every week, take the 2-minute quiz or book a call with Ryan.
Built by Ryan Spiteri, NewU head coach. Last reviewed October 2026.
This calculator gives general estimates for healthy adults and isn't medical advice. If you're pregnant or breastfeeding, under 18, have a medical condition or a history of disordered eating, talk to your GP or an Accredited Practising Dietitian before changing how you eat.