Macro Calculator – Protein, Carbs and Fat
Estimate daily calories and protein, carb, and fat targets from your age, sex, height, weight, activity, goal, and preferred calorie split.
Set Your Daily Protein, Carb and Fat Targets
Macros Formula
Where:
- \(w\) — weight in kilograms; \(h\) — height in centimeters; \(a\) — age in years.
- \(b\) — \(-161\) for Female or \(+5\) for Male, as used by the Mifflin–St Jeor equation.
- \(A\) — selected activity multiplier, from 1.2 to 1.9.
- \(\Delta\) — goal adjustment: \(-500\), 0, or \(+300\) kcal/day for loss, maintenance, or gain.
- \(F\) — calculator minimum: 1,200 kcal/day for Female or 1,500 kcal/day for Male.
- \(E\) — target calories per day; \(p_m\) — a macro’s percentage of calories; \(g_m\) — its daily grams.
- \(k_m\) — 4 kcal/g for protein and carbs, or 9 kcal/g for fat.
The calculator estimates maintenance calories from basal metabolic rate (BMR) and activity, applies the goal adjustment, then enforces its calorie minimum. It converts each macro’s share of target calories into grams.
Macros – Calculation Example
Example: using the default settings—a 30-year-old female, 165 cm tall and 70 kg, moderately active, maintaining weight, with a balanced 30% protein, 40% carbs, and 30% fat split across three meals.
\[ \begin{aligned} \mathrm{BMR} &= 10(70)+6.25(165)-5(30)-161=1{,}420.25\ \mathrm{kcal/day} \\ E &= 1{,}420.25(1.55)=2{,}201.3875\ \mathrm{kcal/day} \\ \text{Protein} &= \frac{2{,}201.3875(0.30)}{4}=165.1\ \mathrm{g/day} \\ \text{Carbs} &= \frac{2{,}201.3875(0.40)}{4}=220.1\ \mathrm{g/day} \\ \text{Fat} &= \frac{2{,}201.3875(0.30)}{9}=73.4\ \mathrm{g/day} \end{aligned} \]
Result: approximately 2,201 kcal/day, with 165.1 g protein, 220.1 g carbs, and 73.4 g fat. Divided equally among three meals, that is about 55.0 g protein, 73.4 g carbs, and 24.5 g fat per meal.
How to use the calculator
- Select Sex and enter Age. The sex selection determines which constant the BMR equation uses.
- Choose Height format. Enter Height in centimeters, or use Height: feet and Height: inches. Enter Weight and choose kg or lb under Unit.
- Choose the Activity level that best represents both your usual exercise and daily movement. Then set Goal to weight loss, maintenance, or gain.
- Select a Diet split. If you choose Custom percentages, enter Custom protein, Custom carbs, and Custom fat; they must total 100%.
- Choose Meals per day to see an equal-meal breakdown. Read Target calories, Macros per day, Macros per meal, and Calorie split in the results.
What your macro targets mean
Macronutrients—protein, carbohydrates, and fat—supply most of the calories in food. This calculator starts with an estimate of the energy your body uses at rest, called BMR. Multiplying BMR by your selected activity factor gives an estimate of total daily energy expenditure (TDEE), or maintenance calories. Your goal changes that estimate by −500 kcal/day for weight loss, 0 for maintenance, or +300 kcal/day for gain.
A diet split describes percentages of calories, not percentages of grams. Protein and carbs each contribute about 4 kcal per gram, while fat contributes about 9 kcal per gram. Consequently, a 30% protein and 30% fat split produces different gram targets. The preset options are ways to distribute the calorie target; they are not requirements for achieving a particular goal.
Use the daily figures as starting targets rather than exact amounts you must hit at every meal. The per-meal figures simply divide each daily target by the selected number of meals. You can distribute food differently across the day while keeping the same daily totals. Displayed calorie and gram values are rounded, so calculating calories back from the displayed grams may give a slightly different total.
Assumptions and practical limits
TDEE is an estimate, not a measurement. People with the same height, weight, age, and reported activity may use different amounts of energy. An activity level that overstates or understates your usual movement can meaningfully change the result. If you are tracking your intake, compare your weight trend over several weeks with your goal before deciding whether to adjust calories.
The calculator will not set a target below 1,200 kcal/day for Female or 1,500 kcal/day for Male. If your selected loss goal falls below that minimum, the result shows the raised target; it no longer represents the full 500 kcal/day reduction. These floors are calculator rules, not a guarantee that a target is appropriate or nutritionally adequate for every person. The stated rate of weight loss and any weight gain are estimates, not promises.
The Mifflin–St Jeor calculation uses a Female or Male constant and does not account for individual differences in body composition or circumstances that can change energy needs. For pregnancy, breastfeeding, a medical condition, or a history of disordered eating, seek individualized guidance rather than relying on this estimate alone.
The carb target here is based on total carbohydrate grams; it does not subtract fiber or other components. If you track those separately, the net carbs calculator and daily fiber intake calculator can help you interpret food labels. For an exercise-specific carbohydrate estimate, use the daily carbohydrate intake calculator.
Frequently Asked Questions
How can I calculate macro grams by hand?
Start with your daily calorie target and multiply it by each macro’s share of calories. Then divide protein and carbohydrate calories by 4, and fat calories by 9. For example, at 2,000 kcal with a 25% protein, 45% carb, and 30% fat split, the targets are 125 g protein, 225 g carbs, and about 67 g fat per day.
What is a good protein, carb, and fat ratio?
There is no single best ratio for everyone. A useful split depends on your food preferences, training, health needs, and whether you can sustain it. Protein needs are often more helpful to consider in grams per kilogram of body weight than as a fixed percentage. Treat any preset as a starting point, and seek individualized advice if you have a medical condition or dietary restrictions.
How much protein do I need per kilogram or pound of body weight?
For generally healthy adults, the recommended dietary allowance is 0.8 g per kilogram of body weight per day, or about 0.36 g per pound. People doing regular resistance training often aim higher; roughly 1.2–2.0 g/kg (0.55–0.91 g/lb) is a commonly used range. More is not automatically better. Ask a clinician about your target if you have kidney disease or another relevant condition.
How do I convert pounds and feet to the metric units used in the formula?
Multiply pounds by 0.45359237 to get kilograms. For height, multiply total inches by 2.54 to get centimeters; total inches equal feet times 12, plus any remaining inches. For example, 5 ft 6 in is 66 in, or 167.64 cm. If you enter pounds or feet and inches in the calculator, it performs these conversions before estimating your calorie target.
Should I add exercise calories to my macro target?
Usually not if your chosen activity level already reflects your typical workouts and daily movement. Adding all the calories reported by a watch or exercise machine could count that activity twice, and those estimates can be inaccurate. If your training changes substantially, reassess your activity level and compare your intake with your weight trend over time rather than automatically eating back each workout estimate.
Will choosing the keto split put me in ketosis?
Not necessarily. Ketosis depends on your actual carbohydrate intake, individual response, and other factors—not simply the name of a preset. Because this calculator sets carbs as a percentage of calories, a higher calorie target also gives a higher carb allowance in grams. If you follow a ketogenic diet for a medical reason, use a plan supervised by an appropriate healthcare professional.
Why don't the calories on food labels exactly match my tracked macros?
Food labels round serving sizes, macro grams, and calories, so the numbers may not reconcile exactly. Fiber, sugar alcohols, alcohol, and differences in how foods are measured or entered in a tracking app can also affect the comparison. Check whether your entries use cooked or uncooked weights and whether you logged the amount you actually ate. Small discrepancies are normal.