Macro Calculator: Protein, Carbs and Fat Targets
Enter your daily calorie target and choose a macro split. The calculator shows your protein, carbohydrate, and fat targets in grams, the calorie contribution of each macro, and how those grams break down across four meals. Select a preset or enter custom percentages that add up to 100.
Targets are estimates based on calorie density factors (4/4/9 kcal/g). Not medical or nutritional advice.
Daily grams
Calorie breakdown
Calorie share
Per meal (÷ 4)
How it works
Each macronutrient supplies a fixed number of calories per gram: protein and carbohydrates each provide 4 kcal/g, while fat provides 9 kcal/g. These are called the Atwater factors and are the basis of all nutrition labels. The calculator multiplies your daily calorie goal by each macro's percentage share to get its calorie contribution, then divides by the relevant factor to produce the gram target. Because fat is more than twice as calorie-dense as protein or carbs, a 30% fat allocation produces far fewer grams than a 30% protein allocation at the same calorie level.
The three presets represent common starting-point splits. Balanced (30/40/30 P/C/F) suits most people eating a moderate mixed diet and mirrors general public-health guidance. Low-carb (40/20/40) reduces carbohydrate to roughly half the balanced level and raises protein and fat proportionally — it is often used in ketogenic-adjacent approaches or by people who find lower carbohydrate intake beneficial for satiety. High-protein (40/30/30) keeps carbohydrate moderate while pushing protein to the upper end of common recommendations, which is popular in body-composition and strength-training contexts where muscle-protein synthesis is a priority.
Working in grams rather than percentages makes tracking practical. Percentages shift with every change in total calories, so a target of '30% protein' means different gram amounts on a 1600-calorie day versus a 2400-calorie day. Grams are fixed, which makes label-reading, food-logging, and meal planning straightforward. The per-meal column assumes four equal meals and is a convenience reference — it is not a prescription for meal frequency.
Frequently asked questions
How much protein do I really need?+
Common research-based ranges are 0.8 g/kg of bodyweight per day for sedentary adults (the approximate RDA), rising to 1.6–2.2 g/kg for people doing regular resistance training who want to support muscle retention or growth. Some studies suggest intakes up to 3.1 g/kg may be safe and beneficial in specific athletic contexts. Individual needs vary substantially based on age, training status, total calorie intake, and health status. This calculator does not know your bodyweight, training load, or health history, so it cannot give you a personalised target. These figures are informational only and are not medical or nutritional advice — if you have health conditions, consult a registered dietitian before making significant changes to your diet.
Do macros matter more than calories?+
For bodyweight change, total calorie balance is the dominant factor — the macronutrient split affects how those calories are partitioned (muscle vs fat) rather than whether weight goes up or down. That said, protein has a meaningful effect on satiety and muscle retention, and different macro distributions can influence how easy a calorie deficit is to sustain. In practice, hitting a reasonable calorie target with adequate protein covers the majority of body-composition goals; obsessive precision over every carbohydrate gram is rarely necessary for non-competitive contexts.
How strict should I be?+
Most nutrition researchers suggest aiming within roughly 5–10 g of your protein and fat targets and within 10–15 g for carbohydrates on a day-to-day basis. Perfect daily adherence is neither realistic nor necessary; what matters is consistency over weeks and months. Sustainable tracking is better than precise tracking that you abandon after two weeks. If logging every gram causes stress, focusing on protein alone — hitting your protein target and eating intuitively otherwise — is a simpler approach that works well for many people.