Diet Calorie & Macro Calculator
Pick your sex, age, height, weight, activity, and goal — get a daily calorie target plus protein, fat, and carb grams in one shot. Free, all in your browser.
※ BMR uses the Mifflin-St Jeor equation; the target multiplies TDEE by 0.80 (lose) / 1.00 (maintain) / 1.10 (gain). Macros use 1.6g protein/kg and 25% fat, with carbs as the remainder. Individual needs vary; this is not medical or nutritional advice.
🔒 Your inputs are calculated in the browser and never sent to a server.
What this calculator does
Unlike a maintenance-only calculator, this tool turns your stats into an action plan. From your sex, age, height, weight, and activity level it estimates your total daily energy expenditure (TDEE), applies your chosen goal — lose, maintain, or gain — to produce a daily calorie target, and then splits that target into grams of protein, fat, and carbohydrate. It answers not just 'how much do I burn?' but 'what and how much should I actually eat?' Hit your calorie target and your protein target and most of your diet planning is done; adjust every few weeks based on the scale.
The formula behind the numbers
BMR uses the Mifflin-St Jeor equation: 10×weight(kg) + 6.25×height(cm) − 5×age, then +5 for men or −161 for women. Multiplying BMR by an activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 active, 1.9 very active) gives TDEE — your maintenance calories. A goal factor finishes the job: 0.80 to lose (about a 20% deficit, roughly 400–600 kcal a day), 1.00 to maintain, and 1.10 to gain. Choose your activity level honestly, since an over-optimistic pick inflates every number downstream.
How the macros are split
Protein defaults to 1.6 g per kg of body weight — inside the ISSN's 1.4–2.0 g/kg range for active people and high enough to protect lean mass in a deficit. Fat takes 25% of goal calories (within the 20–35% AMDR band), divided by 9 for grams. Whatever calories remain go to carbohydrate, divided by 4. Raise protein and carbs fall so total calories stay fixed. These are planning estimates, not a medical prescription — and nothing you type ever leaves your browser.
Frequently asked questions
How is this different from a BMI or body calculator?
A body/BMI calculator tells you your current shape and your maintenance calories. This one adds a goal-based calorie target (lose, maintain, or gain) and breaks it into protein, fat, and carb grams, so you can actually build a daily menu instead of just reading a maintenance number.
Why 1.6 g of protein per kg? Can I go higher when cutting?
The ISSN recommends 1.4–2.0 g/kg for active people to build and keep muscle, and 1.6 g/kg is a defensible default. During a calorie deficit or heavy resistance training, 1.8–2.2 g/kg is reasonable to preserve lean mass — the extra protein simply comes out of your carbohydrate allowance.
Is a 20% deficit safe, and how fast will I lose?
A roughly 20% cut (often 400–600 kcal/day) is a moderate deficit for most people. Aim for 0.5–1% of body weight per week and keep your target from dropping far below your BMR. These are estimates for planning, not a medical prescription — see a professional if you have health conditions.
Does my data get uploaded anywhere?
No. Every calculation runs entirely in your browser. Your sex, age, height, and weight are never sent to a server and are not stored.