How are the macros calculated?

Your daily calories are divided across protein, carbs and fat by the percentage split you choose. Protein and carbs provide 4 kcal per gram and fat provides 9 kcal per gram, so we convert each share of calories into grams.

Which macro split should I use?

Balanced (30/40/30) suits most people. Higher protein helps preserve muscle when losing weight, while keto (very low carb) shifts most calories to fat. Pick the one that matches your diet and goals.

Do you store my numbers?

No — the calculation happens entirely in your browser and nothing is uploaded or saved.

How many calories are in protein, carbs and fat?

Protein and carbohydrate each provide 4 kcal per gram; fat provides 9 kcal per gram (more than double). That is why a high-fat keto split produces far fewer total grams of food than a balanced or high-carb split at the same calories.

What are the keto macros?

This tool uses a 25/5/70 split for keto — 25% of calories from protein, 5% from carbs and 70% from fat. On 2,000 kcal that is about 125 g protein, 25 g carbs and 156 g fat, keeping carbs low enough to support ketosis.

How much protein should I eat to keep muscle?

A common target is 1.6–2.2 g of protein per kg of body weight. The high-protein (40/40/20) split here gets most people into that range; check the gram figure against your weight and nudge the split if needed.

Why do the gram totals change when I switch splits but calories stay the same?

Because fat is 9 kcal/g while protein and carbs are 4 kcal/g, shifting calories toward fat lowers total grams and shifting toward carbs/protein raises them. The calorie total is fixed; only how it is divided changes.

What is the Macro Calculator?

Free macro calculator — turn your daily calorie target into protein, carbohydrate and fat goals in grams using balanced, low-carb, high-protein or keto splits. Runs entirely in your browser, nothing is uploaded. It runs free in your browser on Gera Tools, with nothing uploaded.

Macro Calculator — Gera Tools

Name: Macro Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

Macro calculator

Once you know your daily calorie target, this macro calculator turns it into grams of protein, carbohydrate and fat — the numbers you actually track in a food app. It is for anyone following IIFYM (“if it fits your macros”), keto, or a high-protein cut who needs concrete daily gram goals rather than a vague calorie figure. Pick a preset split and read off your targets.

How it works

Each preset assigns a percentage of your total calories to each macro. The tool multiplies your calories by each percentage to get calories-per-macro, then divides by the energy density of that macro to get grams: 4 kcal/g for protein and carbs, 9 kcal/g for fat.

Split	Protein	Carbs	Fat
Balanced	30%	40%	30%
Low carb	40%	20%	40%
High protein	40%	40%	20%
Keto	25%	5%	70%

Example

A 2,000 kcal day on the balanced (30/40/30) split:

Protein: 2,000 × 0.30 = 600 kcal ÷ 4 = 150 g
Carbs: 2,000 × 0.40 = 800 kcal ÷ 4 = 200 g
Fat: 2,000 × 0.30 = 600 kcal ÷ 9 = 67 g

Set your daily calories with the TDEE or calorie-deficit calculator first, then split them here. Everything runs in your browser — nothing is uploaded.

Getting your calorie target first

Before splitting macros, you need a daily calorie number. Common approaches:

TDEE (total daily energy expenditure): multiply your BMR by an activity factor. Use a TDEE calculator for this step.
Calorie deficit for weight loss: a deficit of roughly 500 kcal/day below TDEE tends to produce about 0.5 kg of weight loss per week, a commonly cited rate that preserves muscle better than aggressive cuts.
Calorie surplus for muscle gain: a modest surplus of 200–300 kcal/day above maintenance is a typical recommendation for minimizing fat gain while building muscle.

Once you have a target, this tool splits it into concrete gram goals.

How to choose your split

The four presets each suit different goals:

Balanced (30/40/30) is a sensible all-round starting point with adequate protein and a moderate carbohydrate level. Suitable for general fitness, maintenance, or anyone not following a specific protocol.

Low carb (40/20/40) reduces carbohydrate enough to moderate insulin response and shift the body toward fat oxidation, without going as low as keto. Popular for fat loss phases and metabolic health.

High protein (40/40/20) maximizes protein to support muscle preservation during a calorie deficit. The extra protein also has the highest thermic effect (the body burns more calories digesting protein than carbs or fat) and tends to increase satiety.

Keto (25/5/70) drops carbs to around 25 g/day on a 2,000 kcal target — low enough to push most people into ketosis, where the liver produces ketone bodies from fat as the primary fuel source. The high fat percentage supplies the calories that carbs no longer provide.

Protein: the most important macro to get right

Protein drives muscle protein synthesis and is also the hardest to overeat because it is highly satiogenic. A widely cited range in sports nutrition is 1.6–2.2 g per kg of body weight per day for people doing resistance training. For someone weighing 75 kg that is 120–165 g of protein per day. Check the gram output from this tool against your body weight to see whether your chosen split puts you in that range — if not, shift the protein percentage up.

Fat is not the enemy

Fat had a poor reputation for decades due to flawed research and dietary guidelines since revised. Dietary fat provides fat-soluble vitamins (A, D, E, K), supports hormone production (including testosterone and estrogen), and makes food palatable. The minimum healthy intake is roughly 0.5–1 g per kg of body weight. On a keto split, fat becomes the primary calorie source, not an enemy — the body adapts to oxidize it as fuel when carbohydrate is very low.