How to Calculate Your Macros (2026): Protein, Carbs, Fat
Most macro advice stops at a number: “eat 150g of protein.” Nobody explains where that number came from, so the second your goal changes, your weight changes, or you just want to try a different split, you’re back to guessing. That’s backwards. The math behind macros is five minutes of arithmetic, and once you actually understand it, you can recalculate for any goal in your head.
This post walks through that math, compares the four diet styles people actually use, and points you at a free macro calculator that does the whole thing for you — from your stats straight to grams, no spreadsheet required.
Enter your stats, pick cut, maintain, or bulk, pick a diet style, get protein, carb, and fat grams instantly.
Open Macro Calculator →- Calories decide the scale. Macros decide the rest.
- The macro math, step by step
- The four diet styles, compared
- How much protein you actually need
- Macros for weight loss, specifically
- What a macro calculator can’t see
- Tools that pair with this one
- FAQ
Calories Decide the Scale. Macros Decide the Rest.
Calories are still the whole ballgame for whether you gain, lose, or hold weight. That part doesn’t change. What macros control is everything a bathroom scale can’t show you: whether the weight you lose is mostly fat or partly muscle, how hungry you are by 3pm, and whether you have the energy to get through a workout or a double shift. Two people eating the identical 2,000 calories a day can end up in very different places after a few months if one of them is eating mostly protein and vegetables and the other is eating mostly bread and soda. Same calorie math. Different results.
The Macro Math, Step by Step
Protein and carbs each supply 4 calories per gram. Fat supplies 9 calories per gram. That difference is the entire reason a "30% fat" diet and a "75% fat" diet (keto) don’t look nearly as different on a plate as the percentages suggest — fat is more than double the energy density of the other two macros.
The calculation itself is four steps:
- Get a daily calorie target (your TDEE, adjusted for cutting, maintaining, or bulking).
- Pick a split: what percent of those calories should be protein, carbs, and fat.
- Protein grams = (calories × protein%) ÷ 4. Carb grams = (calories × carb%) ÷ 4.
- Fat grams = (calories × fat%) ÷ 9.
Worked example: a 2,075-calorie target (a 20% cut from a 2,594 TDEE) on a Balanced split (30% protein / 40% carbs / 30% fat). Protein = (2,075 × 0.30) ÷ 4 = 156g. Carbs = (2,075 × 0.40) ÷ 4 = 208g. Fat = (2,075 × 0.30) ÷ 9 = 69g. Multiply back out and you land within a couple calories of the original target — the rest is just rounding.
The Four Diet Styles, Compared
| Style | Protein | Carbs | Fat | Best for |
|---|---|---|---|---|
| Balanced | 30% | 40% | 30% | General health, sustainable long-term |
| High Protein | 40% | 30% | 30% | Cutting, preserving muscle on a deficit |
| Low Carb | 35% | 20% | 45% | Steadier energy, fewer appetite swings |
| Keto | 20% | 5% | 75% | Strict carb restriction, ketosis |
None of these is objectively correct. Balanced is the easiest one to actually stick to for years, which counts for more than people give it credit for. High Protein earns its keep specifically on a cut. Low Carb and Keto trade flexibility for appetite control, and in keto’s case, a real metabolic shift toward burning fat for fuel — harder to sustain, not required for fat loss, but a legitimate option if it works for you.
Pick a diet style and watch the grams update live as you change your stats or goal.
Launch Macro Calculator →How Much Protein You Actually Need
Protein gets singled out for a reason: your body can’t manufacture it efficiently from the other two macros, and your muscles depend on it directly. Sports nutrition research generally supports 0.7 to 1 gram per pound of bodyweight for people trying to build or keep muscle, with some benefit up to roughly 1.2g/lb during an aggressive cut, when your body is more likely to break down muscle for energy alongside fat.
That bodyweight number is worth keeping in your back pocket, because percentage splits can drift away from it at unusual calorie levels. On a very low-calorie target, even a 40% protein split might land under the bodyweight-based floor. On a large surplus, even 20% can land well above it. When the two disagree, the bodyweight number is the one with research behind it.
Macros for Weight Loss, Specifically
A calorie deficit is what drives fat loss. No macro split changes that. What the split changes is how the deficit feels and what, specifically, you lose along with the fat. A higher-protein split (35 to 40% of calories) is the most consistently supported choice for cutting: protein is the most filling macro gram for gram, and it gives your body a reason to protect muscle instead of burning it for fuel right alongside the fat. If you only adjust one macro while cutting, protein is the one worth protecting.
What a Macro Calculator Can’t See
Any macro calculator inherits the same honest limits as the TDEE calculation underneath it: the starting calorie number runs 10 to 20% off for a given person, since it’s built from population averages, not your actual metabolism. The percentage splits above are common, well-documented starting points — not a prescription from a dietitian who knows your labs, your medications, or a condition like kidney disease or diabetes that changes the macro math entirely. Treat the output as a two-to-three-week starting point. Track how you feel and what the scale does, then adjust the calories or the split — not both at once, so you can actually tell what moved the needle.
Tools That Pair With This One
Run these in sequence, all free, all client-side:
- Macro calculator — protein, carb, and fat grams for your goal and diet style.
- TDEE calculator — the calorie target the macro calculator builds on.
- BMI calculator — a quick check on where you're starting from.
FAQ
Is the CyberScryb macro calculator really free?
Yes. No signup, no account, no paywall. It runs entirely in your browser.
Do I need to know my TDEE before using a macro calculator?
No. The CyberScryb macro calculator computes your TDEE for you from the same inputs (sex, age, height, weight, activity), then splits it into macros, so you only fill out one form.
Which diet style should I pick?
Balanced if you just want a sustainable everyday split. High Protein if you’re cutting and want to hold onto muscle. Low Carb or Keto if you specifically want lower carbs for appetite control or a ketogenic diet.
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