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Macro Calculator

Splits a daily calorie target into grams of protein, carbohydrate and fat using a preset ratio (balanced, low-carb, high-protein, keto) or custom percentages.

When to use

You have a calorie target (from tdee) and want gram targets for each macronutrient.

Do not use when: Medical diets (renal, diabetic, PKU) are involved; those need individualised prescriptions.

Formula

grams = calories × percent / (4 kcal/g for protein and carbohydrate, 9 kcal/g for fat)

Inputs

Parameter	Type	Unit	Required	Description
`calories_per_day`	number	kcal/day	yes	Daily calorie target. Range: ≥ 500, ≤ 10000
`preset`	enum: balanced \| low_carb \| high_protein \| keto \| custom		default balanced	Macronutrient ratio preset. Choose custom to supply your own percentages.
`protein_percent`	number	%	no	Only for preset=custom. Range: ≥ 0, ≤ 100
`carbs_percent`	number	%	no	Only for preset=custom. Range: ≥ 0, ≤ 100
`fat_percent`	number	%	no	Only for preset=custom. Range: ≥ 0, ≤ 100

Outputs

Output	Type	Unit	Description
`protein_g`	number	g/day	Protein grams (4 kcal/g).
`carbs_g`	number	g/day	Carbohydrate grams (4 kcal/g).
`fat_g`	number	g/day	Fat grams (9 kcal/g).
`ratio`	string		Protein/carbs/fat percentages applied.

Example

2000 kcal balanced: {"calories_per_day":2000,"preset":"balanced"} → {"protein_g":150,"carbs_g":200,"fat_g":67,"ratio":"30/40/30"}

2200 kcal custom 35/35/30: {"calories_per_day":2200,"preset":"custom","protein_percent":35,"carbs_percent":35,"fat_percent":30} → {"protein_g":193,"carbs_g":193,"fat_g":73}

GET https://tttkmbb.com/api/v1/calculate/macros?calories_per_day=2000&preset=balanced

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/macros (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/macros · Markdown: https://tttkmbb.com/health/macros.md · JSON definition: https://tttkmbb.com/health/macros.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="macros"
OpenAPI operationId: calculate_macros
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

Which preset should I use?

Balanced suits most people; high-protein helps preserve muscle in a deficit; keto requires carbs below ~50 g/day and is not suitable for everyone.

Do the percentages have to sum to 100?

Yes for custom ratios; the calculator returns an error otherwise.

Related calculators

TDEE Calculator — Get the calorie target first.
Protein Intake Calculator — Check protein against body-weight based recommendations.