Use a macro calculator to estimate daily calories and divide them into protein, carbohydrate, and fat targets. The output is a starting point based on your inputs, not a measurement of your exact needs.
After keeping a consistent record, compare intake with bodyweight and training. That review helps you decide whether to retain or adjust the targets.
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TDEE calculator
Estimate maintenance calories with the Mifflin-St Jeor equation. Change any input to update the result instantly.
Estimated maintenance
2,760 kcal/day
Estimated resting energy
1,783 kcal/day
This is a population-based starting estimate, not a diagnosis or a guarantee. Activity multipliers are especially rough; compare the result with two to four weeks of consistent intake and bodyweight data.
Step one: a starting point, stated as one
The calculator above uses the Mifflin-St Jeor resting-energy equation and an activity multiplier. The same estimate the TDEE calculator guide walks through in detail, including why the activity dropdown is where most of the error lives. Pick the activity level you honestly average across a normal month rather than the one that describes your best week.
Every macro split starts from that calorie total. Tell the coach your goal, height, weight, age, activity, and training schedule, and it produces a starting calorie target and macro split with the reasoning attached: a protein target worth hitting, a deliberate surplus or deficit sized to the goal, and the rest allocated by preference. The number is explicitly an estimate, because that is what it is.
“Set starting macros for a slow cut. Protein first, moderate deficit, and tell me exactly what we're watching over the next two weeks to know if the numbers are right.”
How to calculate macros, in four steps
This is the whole method, and it runs in one direction. Each step takes the previous number as its input.
- Estimate maintenance. The calculator above, or better, the back-calculation from your own logs in the TDEE calculator guide.
- Adjust for the goal. Subtract a deficit to lose, add a small surplus to gain, or stay put to maintain. The calorie deficit calculator sizes the subtraction from your bodyweight and the rate you want rather than defaulting to a flat 500.
- Set protein as a fixed number. Commonly 1.6–2.2 g per kg of bodyweight for people who lift, and toward the top of that or above while dieting. The protein calculator scales the published bands to your weight and goal.
- Divide what is left between carbs and fat. That is the step below, and it is the one most macro split calculators hand you as a fixed percentage without explaining where it came from.
How much protein, carbs, and fat should you eat?
Protein and calories are settled by the first three steps. What remains is a pool of calories to divide, and the arithmetic is simple once you know that protein and carbohydrate provide about 4 calories per gram and fat about 9.
Work it in this order:
- Set a fat floor first. Fat is not optional. It carries fat-soluble vitamins and supports hormone production. A common floor is roughly 0.5–0.6 g per kg of bodyweight, or about 20% of calories, whichever is higher. Going far below that for months is where people start feeling flat and miserable rather than merely hungry.
- Give the rest to carbohydrate. Carbs are the fuel for hard training, and for most lifters the remaining calories are better spent there than on extra fat.
- Then move the line to suit you. Someone who trains hard five days a week usually feels better with more carbs; someone who trains twice a week and prefers larger, richer meals usually feels better with more fat. Neither choice changes the calorie total, so neither changes the direction of the scale.
A worked example, so the division is concrete. Say the steps above landed you at 2,200 calories and 160 g of protein at 80 kg:
| Step | Calculation | Result |
|---|---|---|
| Protein | 160 g × 4 | 640 kcal |
| Fat | Floor is 80 kg × 0.6 = 48 g; this example sits above it at 60 g × 9 | 540 kcal |
| Remaining for carbs | 2,200 − 640 − 540 = 1,020 ÷ 4 | 255 g |
| Starting split | 160 P / 255 C / 60 F |
Prefer richer food? Move 20 g of carbs to about 9 g of fat and the total barely moves. That is the entire flexibility of a macro split: the calorie line holds, and the composition follows your appetite and your training.
Macros for cutting are the same arithmetic with a smaller total and one change in emphasis: protein goes up, not down, because in a deficit it is the number protecting the muscle you are trying to keep. Fat and carbs both give ground. In a surplus the reverse applies: carbs usually absorb most of the extra, since that is what fuels the training the how to build muscle guide says has to keep getting harder. If you are chasing both directions at once, the body recomposition guide covers what that actually asks of these three dials.
Precision beyond this rarely changes a decision. Set the right effort level for tracking each number in the macro tracking guide: for many people, calories and protein tracked well beat all three tracked badly.
Step two: let reality grade the estimate
Log meals for a couple of weeks with the low-friction calorie workflow and log your weight most mornings. Now the question “are my macros right?” has an empirical answer: if intake averaged near target and the weight trend moved as intended, the estimate was good. If not, the coach adjusts the target by what the trend showed. No new formula required.
This adjust-from-evidence loop is the same idea behind dedicated adaptive nutrition apps, which is exactly the comparison drawn in the MacroFactor alternative guide: except here the loop runs inside the same logbook as your training, sleep, and coaching history, so a stalled cut can be read next to a stalled squat.
The logging is what makes step two possible, and it is deliberately unremarkable: describe the meal in a sentence, photograph it, or send a photo of the barcode and ChatRPE looks the product up rather than estimating it. The food barcode scanner guide covers that precision ladder.
Ask for daily intake and bodyweight over the same period, with a moving average where useful. Numeric summaries use a bounded set of entries, so check the included dates. The reported trend compares the first and second halves of the period; it is not a statistical test.
If intake tracked the target and the weight did not move as planned, the target was wrong, not you. If the weight moved for six weeks and then stopped, the weight loss plateau guide covers which of the usual suspects to check before cutting calories again.
If you are managing a medical condition, pregnant or postpartum, taking medication that affects appetite or weight, or have a history of disordered eating, set your intake with a clinician and use the calculator as a reference rather than a prescription.
Frequently asked questions
How do I calculate my macros?
Start from an estimated maintenance calorie level, adjust it toward your goal (a moderate deficit to cut, a small surplus to gain), set a protein target, and split remaining calories between carbs and fat by preference within a sensible fat floor. Then (most importantly) correct the numbers against your real intake and weight trend after a couple of weeks.
How much protein, carbs, and fat should I eat a day?
Protein first: commonly 1.6–2.2 g per kg of bodyweight if you lift. Fat next, with a floor around 0.5–0.6 g per kg or roughly 20% of calories. Carbohydrate takes whatever calories are left. That order matters more than the exact percentages, because it puts the two numbers with real physiological floors ahead of the one that is mostly fuel and preference.
What is the best macro split for cutting?
The one that keeps protein high and calories where you set them. In a deficit, protein is the number protecting your muscle, so it goes up rather than down while carbs and fat share the reduction. Beyond that, the split that works is the one you can actually eat for twelve weeks. A "perfect" ratio you abandon in February is worse than an imperfect one you keep.
Do I need my exact maintenance calories to set macros?
No. A starting estimate is enough, because the split you build on top of it is corrected by the same two-week review either way. If you want the maintenance number itself to be right first, the TDEE calculator covers how to recover it from your logged intake and weight trend instead of trusting a formula.
How much of my calories should be protein?
Set protein as a fixed target first, then build carbs and fat around what is left. Most people who lift land between 1.6 and 2.2 g/kg of bodyweight, and higher while dieting. The protein calculator scales that band to your weight and goal and explains where the numbers come from.
How many calories should I eat to lose weight?
Take your estimated maintenance from the calculator above and subtract a deficit sized to the rate you want rather than a flat 500 kcal. The calorie deficit calculator does that step and explains how big a deficit is workable; come back here to split the resulting target into protein, carbs, and fat.
Does the timing of my macros matter?
Far less than the daily and weekly totals. Getting protein spread reasonably across the day helps a little, and eating something you digest comfortably before training helps your session. The pre-workout food guide covers that without the folklore. None of it competes with hitting the numbers consistently.
What is the best macro calculator?
Any of them will produce a similar first estimate, because they all run the same equations. What separates a useful macro split calculator from a forgettable one is what happens next: whether the number gets checked against what you actually ate and what your weight actually did, or whether you close the tab and re-run it in six weeks. That second half is the part ChatRPE keeps.
Should my macros change over time?
Yes. Bodyweight changes, training changes, and life changes all move the target. Because ChatRPE holds the ongoing log, updating targets is a conversation, not an annual visit to a calculator website.