How to set protein, carb, and fat goals

Start with a calorie estimate and convert your chosen macro percentages to grams. This guide explains the math and shows how MACROS calculates and saves targets.

This guide is for generally healthy adults. It is not medical advice. Talk to a qualified health professional about medical conditions, pregnancy, or an eating disorder before setting diet targets. These adult ranges and the app’s calculator are not a plan for children.

Start with adult reference ranges

The National Academies’ Acceptable Macronutrient Distribution Ranges, or AMDRs, describe shares of total daily calories. For adults, they are:

Nutrient	Share of daily calories
Protein	10–35%
Carbohydrate	45–65%
Fat	20–35%

These are population reference ranges, not a personalized prescription. The National Academies’ AMDR report, Table 3-1 lists these adult values and explains their use in dietary planning. Choose percentages that add to 100%. A 20% protein, 50% carbohydrate, and 30% fat split is one example within all three ranges.

The adult protein Recommended Dietary Allowance, or RDA, is 0.8 grams per kilogram of body weight per day. The National Academies’ DRI summary tables, protein footnote b state this figure. It is a reference intended to meet the needs of nearly all healthy adults, not an upper limit or a sports-performance target. Individual needs can differ.

At 70 kg, the calculation is 70 × 0.8 = 56 g of protein per day. In pounds, 154.3 lb ÷ 2.20462 ≈ 70 kg, so the same calculation gives about 56 g. Do not confuse grams per kilogram with grams per pound.

Turn calories into grams

For planning, protein and carbohydrate each provide 4 calories per gram. Fat provides 9. These are the general factors in FDA nutrition-labeling rules, 21 CFR 101.9(c)(1)(i)(B).

Protein grams = daily calories × protein percentage ÷ 100 ÷ 4.
Carb grams = daily calories × carb percentage ÷ 100 ÷ 4.
Fat grams = daily calories × fat percentage ÷ 100 ÷ 9.

For an illustrative 2,000-calorie day with a 20/50/30 split, that gives 100 g protein, 250 g carbs, and about 66.7 g fat. This is a math example, not a calorie recommendation. Food-label calories may not match 4/4/9 exactly because of rounding, fiber, sugar alcohols, and permitted calculation methods.

From a calorie share to grams

An illustrative 2,000-calorie day with a 20/50/30 split
Macro	Calorie share	Divide by	Grams
Protein	2,000 × 20%	÷ 4	100 g
Carbs	2,000 × 50%	÷ 4	250 g
Fat	2,000 × 30%	÷ 9	66.7 g

Multiply daily calories by the macro's share, then divide by 4 for protein or carbs and 9 for fat. This is a math example, not a calorie recommendation. Fat rounds to about 66.7 g.

How the MACROS calorie estimate works

MACROS uses the Mifflin–St Jeor equation to estimate resting energy needs:

Resting calories = 10 × weight in kg + 6.25 × height in cm − 5 × age in years + a sex constant.

The constant is +5 for Male and −161 for Female. For Unspecified, MACROS uses their midpoint, −78. That midpoint is an app convention, not a separately validated equation. The original Mifflin–St Jeor study studied healthy adults. An estimate cannot measure your individual metabolism.

The app multiplies resting calories by the activity factor you select:

Activity	App description	Multiplier
Sedentary	Mostly sitting, little planned exercise	1.2
Light	Light exercise 1–3 days per week	1.375
Moderate	Moderate exercise 3–5 days per week	1.55
Active	Hard exercise 6–7 days per week	1.725
Very active	Very hard training or a physical job	1.9

These factors are the app’s estimation settings. They are not part of the original resting-energy equation. Maintain uses that total unchanged. Lose subtracts 250, 500, or 750 calories per day for the selected 0.25, 0.5, or 0.75 kg weekly pace. Gain adds 250 or 500 calories for 0.25 or 0.5 kg per week. The pound equivalents are about 0.55, 1.10, and 1.65 lb. These settings do not guarantee a particular weight change.

The calculator clamps its result to at least 1,500 calories for Male or 1,200 for Female and Unspecified. It flags a requested target below that floor. These are software limits, not proof that a calorie target is safe or adequate for you.

The age field starts at 30. If you clear it, the app uses 30 and shows a notice. Weight converts between kg and lb; height converts between centimeters and feet/inches. Changing units retains the underlying metric measurements.

What the app’s macro presets mean

MACROS offers these starting splits before rounding:

Preset	Protein	Carbs	Fat
Balanced	30%	40%	30%
High protein	40%	30%	30%
Low carb	35%	20%	45%

The preset names are product labels, not dietary guidelines. None of these presets falls within all three adult AMDRs. Balanced puts carbs below 45%. High protein also puts protein above 35%. Low carb puts carbs below 45% and fat above 35%. Choose manual goals if you want a split within the reference ranges or targets agreed with a professional.

App presets against adult reference ranges

The shaded bands mark adult AMDRs. Markers show each preset before rounding.

Adult AMDRs compared with MACROS preset calorie percentages
Macro	Adult AMDR	Balanced	High protein	Low carb
Protein	10–35%	30%	40%	35%
Carbs	45–65%	40%	30%	20%
Fat	20–35%	30%	30%	45%

No app preset meets all three adult AMDRs. The ranges come from the National Academies' Table 3-1 cited above. Presets are app settings, not dietary guidelines.

The calculator rounds protein and fat to the nearest 5 g. It first rounds carbs to 5 g too. It accepts a calorie total between the requested total and 2% above it. Outside that range, the app replaces carbs with the smallest 5 g step that reaches the target. That adjustment can raise or lower carbs. It then calculates the displayed calorie goal from the final grams with 4/4/9. The saved goal can therefore differ from the initial calorie estimate.

A worked calculator example in kg and lb

Take a hypothetical 30-year-old adult using Male, 70 kg, 175 cm, Moderate activity, Maintain, and Balanced. This is an explanation of the software, not advice to use these settings.

The resting estimate is 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,648.75 calories.
The activity estimate is 1,648.75 × 1.55 = 2,555.56 calories.
Maintain adds zero. The result is above the app’s calorie floor.
The 30/40/30 split gives about 191.67 g protein, 255.56 g carbs, and 85.19 g fat before rounding.
The app rounds to 190 g protein, 255 g carbs, and 85 g fat. That totals 2,545 calories, below the estimate.
It raises carbs to 260 g. The final goal is 2,565 calories, 190 g protein, 260 g carbs, and 85 g fat.

How this example reaches 2,565 kcal

Resting estimate1,648.75 kcal
10 × 70 + 6.25 × 175 − 5 × 30 + 5
Moderate activity2,555.56 kcal
1,648.75 × 1.55
Maintain+0 kcal
No goal offset. The result is above the calorie floor.
Balanced split30% / 40% / 30%
Protein 191.67 g, carbs 255.56 g, fat 85.19 g before rounding.
Round and adjust2,565 kcal
190 g protein, 260 g carbs, 85 g fat. Carbs rise from 255 g to reach the estimate.

Male, age 30, 70 kg, 175 cm, Moderate, Maintain, Balanced. The app calculates the final calories from rounded grams with 4/4/9.

In imperial units, 70 kg is about 154.3 lb and 175 cm is about 5 ft 8.9 in. Entering those rounded imperial values gives nearly the same estimate and the same rounded macro goals. The app displays height conversions to a whole inch, so switching units may show 5 ft 9 in while retaining the original centimeters internally.

Sources and scope

I am the developer of MACROS, not a medical reviewer. I checked the sources below on November 4, 2026, and compared the calculator explanation with this version of the app.

National Academies, 2024 AMDR report, chapter 3 and Table 3-1: adult percentage ranges and their limits.
National Academies, 2019 DRI summary tables, protein footnote b: adult protein RDA of 0.8 g/kg.
FDA, 21 CFR 101.9(c)(1): general 4/4/9 calorie factors and other labeling methods.
Mifflin et al., 1990, original resting-energy equation: the adult equation used by the app.

Set your daily goals in MACROS

Open Settings and find Daily Goals. Enter your calorie, protein, carb, and fat targets, then tap Save Goals.

MACROS Settings with editable Daily Goals and Recalculate Targets. — Settings > Daily Goals. These demo values show the controls, not the worked example or a recommended diet.

For a calculated starting point, tap Recalculate Targets. Enter your body profile.

Enter the body profile. This example uses Male, age 30, 175 cm, and 70 kg.

Choose your activity and goal direction, then tap Review targets.

Calculator with Moderate activity and Maintain selected under Your goal, above Review targets. — Choose Moderate activity and Maintain for this example. Scroll down in the form to find Your goal.

Check the macro balance and targets before applying them. These calculator screenshots use the worked example above, not a recommended diet.

Your targets review with Balanced macro balance, 2,565 kcal, 190 g protein, 260 g carbs, and 85 g fat. — Review the targets and Macro balance. This Balanced example matches the calculation above.

Revisit your targets with a professional if they do not fit your needs. A macro total alone does not tell you whether your diet provides enough fiber, vitamins, or minerals.

Read how MACROS handles your food diary data or contact the developer for app help. The MACROS calorie counter and food diary homepage lists the app’s features.