daily calorie needs · maintenance, loss & gain targets · macro breakdown
Your details
If you know your body fat %, we'll use the Katch-McArdle formula instead of Mifflin-St Jeor — it's more accurate because it's based on your lean body mass rather than a population average.
BMI
—
—
Ideal weight range
—
avg. of 4 formulas
Maintenance
0
no change
Weight Loss
0
−500 cal · ~0.5 kg/wk
Weight Gain
0
+500 cal · ~0.5 kg/wk
Calories by activity level
Your BMR stays the same — only the multiplier changes. Here's how your maintenance calories would shift at each activity level, so you can double-check you picked the right one.
Level
Cal/day
Ideal body weight
—
Estimated range across 4 classic formulas — these predate BMI and are population averages, not individual targets, especially if you carry significant muscle.
Macro Calculator
Based on — calories/day
Protein
30%
0g
Carbohydrates
40%
0g
Fat
30%
0g
How it works
We calculate your BMR. If you enter your body fat %, we use the Katch-McArdle formula (based on your lean body mass) — the more accurate option when body composition is known. Otherwise we use Mifflin-St Jeor (age, gender, height, weight), the most validated formula for the general population.
We factor in your activity level. BMR × an activity multiplier gives your TDEE (Total Daily Energy Expenditure) — your maintenance calories. The activity comparison table shows how each level would change your number, so you can sanity-check your pick.
Three targets appear. Maintenance (your TDEE), Weight Loss (−500 cal/day, roughly 0.5 kg/week), and Weight Gain (+500 cal/day).
You also get BMI and ideal weight range. Calculated from the same height/weight, using four classic ideal-body-weight formulas (Hamwi, Devine, Robinson, Miller) averaged together.
Pick a macro style. Choose which target to build macros around, then a split (Balanced, High Protein, or Low Carb) to see exact grams of protein, carbs, and fat.
Push it to your tracker. "Use as my goal" sends your chosen calories and protein straight to the Calorie Tracker's daily goal.
These are population-level formulas, not individualized prescriptions — actual metabolism varies by individual, even with body fat % factored in.
Frequently asked questions
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest. TDEE (Total Daily Energy Expenditure) adds your activity level on top of that — TDEE is your actual maintenance calorie number.
A common approach is eating around 500 calories below your TDEE per day, which typically leads to about 0.5kg (1lb) of weight loss per week — shown as the "Weight Loss" target above.
If you don't enter body fat %, it uses Mifflin-St Jeor, one of the most widely validated formulas for estimating calorie needs. If you do enter body fat %, it switches to Katch-McArdle, which is generally more accurate since it's based on your actual lean body mass rather than a population average. Either way, individual metabolism can still vary by 10–15% from the estimate.
Katch-McArdle calculates BMR from your lean body mass (total weight minus fat mass) instead of age and gender averages. Two people with the same height, weight, age, and gender can have very different metabolisms if one carries more muscle — Katch-McArdle accounts for that difference, which is why it's considered more accurate when you know your body fat percentage.
It's an estimated healthy weight range based on your height, calculated using four classic medical formulas (Hamwi, Devine, Robinson, and Miller) that predate BMI. They're population averages from decades-old studies, not individual targets — someone with more muscle mass than average will reasonably weigh more than these ranges suggest.
A higher-protein split (like the "High Protein" option here) is often recommended during a calorie deficit, since it helps preserve muscle mass while losing fat.
Yes — the "Use as my calorie & protein goal" button sends your chosen target directly to the Calorie Tracker's daily goal.
Yes — your age, height, weight, gender, and activity level are saved privately in your browser, so they're pre-filled the next time you visit. Nothing is sent to a server.
Yes — TDEE shifts as your weight changes, since it's partly based on body weight. It's worth recalculating every few weeks, especially during active weight loss or gain, to keep your targets accurate.
Estimates use the Mifflin-St Jeor equation for BMR (or Katch-McArdle if body fat % is provided) and standard 500-calorie deficit/surplus conventions for loss/gain (roughly 0.5 kg or ~1 lb per week). Ideal body weight uses four population-average formulas (Hamwi, Devine, Robinson, Miller). Macro splits are general presets, not personalized prescriptions. Not medical advice — consult a professional for individualized guidance, especially with significant calorie deficits.