Macro calculator — protein, carbs and fat in grams
Split a calorie target into protein, carbs and fat with balanced, low-carb, high-protein or keto presets, shown in grams, calories and percent.
- Runs in your browser
- Nothing you enter is sent
- Free, no account
Not sure? Switch to the estimate tab, or use the TDEE calculator.
The default for general health and mixed training. Enough carbohydrate to fuel hard sessions, enough fat for hormones and satiety.
Macro targets are a planning tool, not a prescription. Anyone with kidney disease, diabetes, or a history of disordered eating should agree a split with a clinician before following one.
30% of calories · 660 kcal · 4 kcal per gram
40% of calories · 880 kcal · 4 kcal per gram
30% of calories · 660 kcal · 9 kcal per gram
| Macro | Per meal | Per day | Calories / day |
|---|---|---|---|
| Protein | 55 g | 165 g | 660 |
| Carbohydrate | 73 g | 220 g | 880 |
| Fat | 24 g | 73 g | 660 |
The formula, with your numbers
- Protein
- 2200 kcal × 30% ÷ 4 kcal/g = 165 g
- Carbohydrate
- 2200 kcal × 40% ÷ 4 kcal/g = 220 g
- Fat
- 2200 kcal × 30% ÷ 9 kcal/g = 73 g
- Check
- (165×4) + (220×4) + (73×9) = 2197 kcal
The Atwater factors — 4 kcal per gram of protein and carbohydrate, 9 for fat — are what convert a percentage split into grams you can weigh.
What this means
165 g protein, 220 g carbs and 73 g fat make up your 2,200 kcal day on the balanced split.
In practice, treat protein as a floor and calories as a ceiling. Hitting protein protects muscle and keeps you full; carbs and fat can move around each other freely to fit real meals, because at matched calories and protein the ratio between them has little effect on fat loss.
Fat should rarely drop below about 0.5 g per kg of body weight — it carries fat-soluble vitamins and supports hormone production. Carbohydrate is the one that most affects how good hard training feels.
How to use the macro calculator
- Enter your daily calorie target, or switch to the estimate tab and let the calculator work one out from your body and activity level.
- Pick a preset — balanced, low carb, high protein or keto — or choose Custom and set the split yourself with the sliders.
- Read the grams. Each macro shows grams, calories and its share of the total, and the per-meal table divides it across however many meals you eat.
- Copy the summary if you want to paste it into a food tracker or a note.
Turning percentages into grams
Macros are usually quoted as percentages of calories, but you eat grams. The conversion uses the Atwater factors:
| Macronutrient | Calories per gram | Thermic effect |
|---|---|---|
| Protein | 4 kcal | 20 – 30% of its own calories burned digesting it |
| Carbohydrate | 4 kcal | 5 – 10% |
| Fat | 9 kcal | 0 – 3% |
| Alcohol | 7 kcal | 10 – 30%, and it suppresses fat oxidation while it is metabolised |
| Fibre | 0 – 2 kcal | Largely unavailable; counted as carbohydrate on most labels |
So 2,000 kcal at 30 percent protein is 2,000 × 0.30 = 600 kcal from protein, and 600 ÷ 4 = 150 g of protein a day.
The presets, and when each one earns its place
| Preset | Protein / Carb / Fat | Best for |
|---|---|---|
| Balanced | 30 / 40 / 30 | General health and mixed training. A sensible default if you are unsure |
| Low carb | 35 / 25 / 40 | People who find carbohydrate hard to moderate, or who prefer steadier energy |
| High protein | 40 / 35 / 25 | Cutting phases and body recomposition — protects muscle and controls hunger |
| Keto | 20 / 5 / 75 | Ketogenic diets; usually under 50 g of carbohydrate a day |
At matched calories and matched protein, the carb-to-fat ratio has very little effect on fat loss. Choose the split you can actually stick to and that fuels your training — that is the variable that decides outcomes.
How much protein?
Protein is the macro worth being deliberate about. The evidence clusters around these figures:
| Situation | Protein per kg of body weight | Per lb |
|---|---|---|
| Minimum to avoid deficiency (RDA) | 0.8 g | 0.36 g |
| Active adult, general health | 1.2 – 1.6 g | 0.55 – 0.73 g |
| Building muscle at maintenance or a surplus | 1.6 – 2.2 g | 0.73 – 1.0 g |
| Cutting while lean, preserving muscle | 2.0 – 2.4 g | 0.9 – 1.1 g |
| Older adults (65+), countering sarcopenia | 1.2 – 1.5 g | 0.55 – 0.68 g |
If you carry a lot of body fat, base the figure on your target weight or lean mass rather than your current weight, or the number gets unrealistically large.
Spread it out. Roughly 0.3 to 0.4 g per kg per meal, three or four times a day, maximises muscle protein synthesis better than the same total in one sitting.
Floors for carbs and fat
- Fat: about 0.5 g per kg minimum, ideally 0.8 to 1.0 g. Dietary fat carries vitamins A, D, E and K, supplies essential fatty acids, and supports sex hormone production. Very low fat intakes are miserable and rarely necessary.
- Carbohydrate: whatever is left, but note the effect on training. Carbs are the main fuel for anything above moderate intensity. If your sessions feel flat, take calories from fat and give them to carbs before you blame anything else.
- Fibre: about 14 g per 1,000 kcal. That is the US Dietary Guidelines figure and it is shown in your results. It helps satiety far more than the macro split does.
Tracking without losing your mind
Hitting three targets exactly, every day, is neither necessary nor realistic. A practical hierarchy:
- Calories set the direction — treat the target as a ceiling.
- Protein sets the composition of what you gain or lose — treat it as a floor.
- Carbs and fat can move freely against each other to fit real meals.
- Judge yourself on the weekly average, not any single day.
Weigh food raw where you can — cooked weights vary with how much water was driven off. And enter cooking oil: a tablespoon is 120 kcal and it is the single most commonly missed entry in a food diary.
Questions
How much protein do I actually need?
For general health, about 0.8 g per kg of body weight is the floor. For building or keeping muscle in a deficit, the evidence supports 1.6 to 2.2 g per kg — the calculator shows where your split lands on that scale.
How many calories are in a gram of each macro?
Protein and carbohydrate supply about 4 kcal per gram, fat about 9 kcal per gram, and alcohol about 7 kcal per gram. Those Atwater factors are what turn a percentage split into grams.
What macro split does keto use?
Roughly 70 to 75 percent of calories from fat, 20 to 25 percent from protein and 5 percent or less from carbohydrate — usually under 50 g of carbs a day, which is what tends to keep ketosis going.
Do I need to hit my macros exactly every day?
No. Weekly averages matter far more than any single day. Most people do well by treating protein as a floor to reach and calories as a ceiling, then letting carbs and fat move around to fit their meals.