Free Macro Calculator: Your Daily Protein, Carbs & Fat
Get a personalized calorie target and macro split for losing fat, maintaining, or building muscle — plus what it looks like meal by meal.
Calculate Your Macros
What are macros?
Macronutrients are the three nutrients your body needs in large amounts. Enter your details to get a daily calorie target and the grams of each you should aim for.
- Protein4 cal per gram
- Carbohydrates4 cal per gram
- Fat9 cal per gram
New to this? Read our beginner's guide to macros.
These targets are estimates based on population formulas and are a starting point, not a prescription. Individual calorie needs vary. If you are pregnant, managing a medical condition, or have a history of disordered eating, speak with a doctor or registered dietitian before changing your intake.
What Are Macros, Quickly
Macronutrients — macros — are the three nutrients your body needs in large amounts: protein, carbohydrates, and fat. Protein and carbs each carry 4 calories per gram; fat carries 9. Every calorie you eat comes from one of them.
Counting macros means tracking grams of each rather than just a calorie total. The advantage is that it tells you where your calories come from, which matters: 2,000 calories weighted toward protein produces a very different result from 2,000 calories that are mostly refined carbs, even though the number on the app is identical.
That's the short version. For the full walkthrough — what each macro does, how to track without it taking over your life, and the mistakes most beginners make — read our beginner's guide to macros.
How to Calculate Your Macros
Every macro calculator, including this one, runs the same three steps. Knowing what's happening behind the button makes the output far more useful — and makes it obvious when a number looks wrong.
Step 1 — Find Your Maintenance Calories
First the calculator estimates your basal metabolic rate (BMR) — the energy your body burns at complete rest keeping your heart beating, lungs working, and brain running. The Mifflin-St Jeor equation is the modern standard and the default here:
Mifflin-St Jeor equation for men.
Mifflin-St Jeor equation for women.
BMR is then multiplied by an activity factor to get total daily energy expenditure (TDEE) — your actual maintenance calories, the amount that holds your weight steady.
1.2 sedentary · 1.375 lightly active · 1.55 moderately active · 1.725 very active · 1.9 extremely active.
The activity multiplier is where most of the error lives. People routinely overestimate how active they are — three gym sessions a week alongside a desk job is "lightly active," not "very active." If your results don't match what the scale does over a few weeks, this is the first input to revisit.
Step 2 — Adjust for Your Goal
Maintenance calories get adjusted up or down depending on what you're after:
- Fat loss: a 10–25% deficit. Around 20% is the usual sweet spot — fast enough to see progress, gentle enough to hold on to muscle and stick with it.
- Maintenance: no adjustment. Useful when you're happy with your weight and want to change body composition through training instead.
- Muscle gain: a 10–20% surplus. A roughly 10% surplus supports lean gains; larger surpluses add muscle marginally faster and fat considerably faster.
Bigger deficits are not better. Beyond about 25%, an increasing share of the weight you lose comes from muscle rather than fat, hunger and fatigue climb sharply, and adherence collapses. This calculator also holds targets at a floor of 1,500 calories for men and 1,200 for women, because below those levels it becomes genuinely difficult to meet basic nutrient needs.
Step 3 — Split Calories Into Macros
Finally the calorie target is divided across the three macros by percentage, then converted to grams using the calories-per-gram value for each:
Protein and carbs: 4 calories per gram. Fat: 9 calories per gram.
Worked example: at a 2,200 calorie target with 35% protein, that's 770 calories from protein, and 770 ÷ 4 gives 193 grams per day.
Macro Ratios for Your Goal
There's no single correct macro split. Total calories drive weight change; the split determines how well you hold muscle, how full you feel, and how much energy you have to train. These are sensible starting points, not rules.
Macros for Fat Loss
A reasonable starting split is 30–40% protein, 30–40% carbs, 20–30% fat. This calculator defaults to 35 / 35 / 30 for fat loss.
Protein does the heavy lifting in a deficit for two reasons. It's the most filling of the three macros per calorie, which makes the deficit easier to hold. And it signals your body to preserve muscle while you're losing weight, so more of what comes off is fat. Keeping carbs moderate rather than cutting them to the floor keeps training quality up, and fat stays high enough to support hormone production.
Macros for Muscle Gain
Shift toward carbs: 25–35% protein, 40–50% carbs, 15–25% fat. The default here is 30 / 45 / 25.
Carbs fuel hard training sessions and replenish the muscle glycogen you burn through them, which is why they take the largest share when the goal is growth. Protein stays high in absolute grams — it just represents a smaller percentage because total calories have gone up. Spreading protein across the day rather than loading it into one meal appears to modestly improve the muscle-building response.
Macros for Maintenance
A balanced 30% protein, 40% carbs, 30% fat works well for most people holding steady. It's flexible enough to live with long term and leaves room to shift in either direction when your goal changes.
Maintenance is underrated. Cycling between fat loss phases and maintenance phases is usually more sustainable — and often produces better long-run results — than staying in a deficit indefinitely.
How Much Protein Do You Actually Need?
Percentage splits are convenient but they scale protein to your calorie target, which isn't quite how protein needs work. A more direct check: most evidence supports 0.7–1.0 grams per pound of body weight (roughly 1.6–2.2 g/kg) for people training regularly, with the upper end favoured during a fat loss phase.
The calculator shows your protein target in grams per pound and per kilogram alongside the percentage, so you can sanity-check it against that range. If a split pushes protein below about 0.7 g/lb, nudge the protein percentage up.
How to Actually Hit Your Macros
Calculating macros takes thirty seconds. Hitting them consistently is the part that decides whether any of it works. A few things that make the difference:
Build Meals Around Protein First
Protein is the macro people most often miss, and it's the one that matters most for body composition. Decide the protein source for each meal first, then fill in carbs and fat around it. Carbs and fat tend to take care of themselves; protein rarely does.
A practical target: roughly a quarter to a third of your daily protein at each main meal. The per-meal breakdown in the results above does this math for you.
Aim for Close, Not Exact
Landing within about 10 grams of each target is fine. Chasing exact numbers turns eating into a maths problem and is the fastest route to abandoning the whole approach. Consistency across a week beats precision on any single day.
It's also worth being honest about the underlying accuracy: food labels are permitted meaningful margins of error, database entries vary, and the formulas behind your targets are population estimates. False precision on top of approximate inputs isn't precision at all.
Reduce the Number of Decisions
Most people fail on macros not from lack of knowledge but from friction — the gap between knowing what to eat and having it ready when you're hungry at 7pm. Anything that shrinks that gap helps: batch-cooking protein at the weekend, keeping a short rotation of meals you know the numbers for, or using pre-portioned meals with the macros already on the label.
The point is to make the right choice the easy one. Willpower is a poor substitute for having food ready.
When to Recalculate
- After every 10–15 pounds of weight change — your calorie needs move with your body weight
- If your activity level changes meaningfully, such as starting or stopping a training block
- Every 4–6 weeks during an active fat loss or muscle gain phase
- If progress stalls for 2–3 weeks while you're hitting your targets consistently
To fill in the rest of the picture, our other free calculators cover BMI, body fat percentage, lean body mass, and heart rate training zones.
Common Questions About Macros
How do I calculate my macros?
Three steps. Estimate your maintenance calories from your height, weight, age, gender, and activity level. Adjust that number up or down for your goal — typically a 20% deficit for fat loss or a 10% surplus for muscle gain. Then split the result into protein, carbs, and fat by percentage and convert to grams, dividing by 4 for protein and carbs and by 9 for fat. The calculator above does all three steps at once.
What is the best macro split for weight loss?
A common starting point is 30–40% protein, 30–40% carbs, and 20–30% fat. Higher protein helps you stay full in a calorie deficit and protects muscle while you lose weight. That said, total calories determine whether you lose weight at all — the split determines how much of the loss is fat rather than muscle, and how sustainable the process feels.
What macros should I eat to build muscle?
Aim for roughly 25–35% protein, 40–50% carbs, and 15–25% fat, paired with a calorie surplus of about 10–20% above maintenance. Carbs take the larger share because they fuel training and restore muscle glycogen. A smaller surplus around 10% supports leaner gains; larger surpluses add fat considerably faster than they add muscle.
How much protein do I need per day?
Most evidence supports 0.7–1.0 grams per pound of body weight (about 1.6–2.2 g/kg) for people who train regularly, with the higher end favoured during fat loss. For a 170 pound person that's roughly 120–170 grams daily. Sedentary adults need less, though there's little downside to the higher range for healthy kidneys.
Do I have to hit my macros exactly?
No. Landing within about 10 grams of each target is fine. Food labels carry meaningful margins of error, nutrition database entries vary, and your calorie target is itself an estimate — chasing exact numbers adds stress without adding accuracy. Consistency across a week matters far more than precision on any single day.
Should I count calories or macros?
Macros include calories — if you hit your macro targets, you've hit your calorie target automatically. Counting macros gives you more information, particularly around protein intake, which is the variable that most affects whether weight loss comes from fat or muscle. If tracking three numbers feels like too much to start with, tracking protein and total calories captures most of the benefit.
What is IIFYM?
IIFYM stands for "If It Fits Your Macros" — an approach where no food is off-limits as long as it fits within your daily targets. Its strength is flexibility and sustainability, since you're not banning entire food groups. Its weakness is that macros say nothing about micronutrients or fibre, so a diet that technically fits your numbers can still be short on the things that keep you healthy.
How often should I recalculate my macros?
Every 4–6 weeks during an active fat loss or muscle gain phase, or after every 10–15 pounds of weight change. Your calorie needs shift as your body weight changes, so a target set at 200 pounds won't be right at 180. Also recalculate if your training volume or daily activity changes meaningfully.
Why am I not seeing results even though I'm hitting my macros?
The most common cause is an overestimated activity level, which inflates your calorie target. The second is untracked intake — cooking oils, drinks, and portions eyeballed rather than measured add up quickly. Give any change 2–3 weeks before judging it, since water weight can mask fat loss entirely in the short term. If everything looks consistent and nothing has moved, reduce your target by about 10% and reassess.
Are macro calculators accurate?
They produce a well-informed starting point, not a precise prescription. The formulas behind them are built on population averages, and individual metabolic rates vary by 10% or more in either direction from the estimate. Treat the output as your opening hypothesis: follow it for a few weeks, watch what actually happens to your weight and energy, then adjust.
