Convert any calorie target to grams of protein, fat and carbs. Diet presets (keto, balanced, high-protein, custom), per-meal breakdown and body-weight protein recommendations.
Built and maintained by Paul Clark, Redmoon Software · Checked against what this tool computes on
| Macro | % | Daily g | Per meal g | kcal |
|---|
Calories per gram: protein 4, carbs 4, fat 9. Grams = (calories × split%) / kcal-per-gram.
Protein recommendation: 0.8 g/kg sedentary, 1.6 g/kg active, 2.2 g/kg cutting (per body weight).
Custom percentages must sum to 100%; otherwise the result shows "—".
The split is pure arithmetic on Atwater factors: protein and carbohydrate at 4 kcal per gram, fat at 9. Grams of each macro equal your calorie target times that macro's percentage, divided by its kcal per gram. So 2200 kcal on the balanced 50/30/20 preset gives 275 g carbs, 73 g fat and 110 g protein. The table then repeats each figure divided by your meals per day and converts back to kcal so you can check the three rows sum to your target.
The preset dropdown is the main lever: Balanced 50C/30F/20P, Keto 5C/65F/30P, Low-carb 20C/40F/40P, High-protein 40C/30F/30P, High-carb 60C/25F/15P, or Custom %. Custom entries must sum to exactly 100 or the result collapses to dashes. Separately, the Protein target selector — Sedentary 0.8 g/kg, Active 1.6 g/kg, Cutting 2.2 g/kg — multiplies your bodyweight to produce an advisory line telling you how far over or under target your chosen split lands.
This tool splits a calorie number you supply; it does not work out what that number should be. There is no BMR, TDEE, activity or goal calculation anywhere in it, so bring a target from elsewhere. The protein recommendation is advisory only — it never rewrites your percentages, so a keto split at low bodyweight can sit well under the suggested grams without any warning. The per-meal column divides evenly, which no real eating pattern does, and Atwater factors are population averages that ignore fibre and alcohol.
165 grams. Protein carries 4 kcal per gram, so 2200 times 0.30 gives 660 kcal, divided by 4. Split across the default four meals that is roughly 41 grams of protein per sitting.
Because your three custom percentages do not add up to 100. The tool allows half a percentage point of slack and then refuses to calculate rather than silently normalising your numbers. Adjust carbs, fat or protein until the three total exactly 100.
The Keto preset uses 5% carbs, 65% fat and 30% protein. On a 2200 kcal target that works out to about 28 g of carbs, 159 g of fat and 165 g of protein per day, before you adjust for your own bodyweight.
The Protein target dropdown offers 0.8 g/kg for sedentary, 1.6 g/kg for active and 2.2 g/kg while cutting. At 80 kg those come to 64, 128 and 176 grams. The note under the table compares your split against whichever you pick.
No. It takes a calorie target as an input — anything from 500 to 10,000 — and divides it into macros. Work out your maintenance calories and your deficit or surplus separately, then bring that figure here to split it.
The presets — balanced, keto, low-carb, high-protein, high-carb — are splits of a calorie target rather than independent recommendations, so the total is what you set and the presets decide only how it is divided. Protein and carbohydrate are about 4 kcal per gram and fat about 9, which is why fat-heavy splits produce much smaller gram figures for a given calorie count.
Keto in particular is defined by keeping carbohydrate low enough in absolute grams to shift metabolism, which is a threshold rather than a percentage — at a high enough calorie target, a percentage-based split can exceed it.
Every split is only as good as the target it divides, and calorie targets from any predictive equation carry meaningful error for an individual — several hundred calories either way is common. Activity multipliers are the least reliable part, since self-reported activity is systematically overestimated.
The practical approach is to treat the number as a starting point, hold it for two or three weeks, and adjust from what actually happens to bodyweight rather than from what the equation predicted. Protein is the macro worth hitting precisely; the fat-carbohydrate split within the remaining calories is largely a preference and adherence question.
The standard or formula behind this tool, so you can check it rather than take it on trust.
Mifflin, M.D. et al. (1990). "A new predictive equation for resting energy expenditure in healthy individuals." American Journal of Clinical Nutrition, 51(2), 241–247.
The Mifflin–St Jeor equation for resting energy expenditure. It predicts a population average; individual requirements vary well beyond its error bars, so treat the output as a starting point to adjust from.
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