A daily calorie target you can actually trust
Plug in your age, sex, weight, height, and how active you are during a typical week. The calculator returns three numbers that matter and one set of macros to start with. BMR is what your body burns to keep you alive if you stayed in bed all day. TDEE is BMR multiplied by an activity factor, the actual number of calories you burn on a real day. Target is TDEE adjusted up or down based on whether you want to lose fat, hold steady, or put on size.
The calculator uses the Mifflin, St Jeor equation. It’s not the only formula in use, but it’s the one nutritionists default to because it tracks reality better than the older Harris, Benedict equation, especially for people outside the “average” demographic the older formula was built around.
Why three numbers, not one
A lot of calorie tools just spit out a single “you need 2,200 calories” answer. That’s misleading. Your BMR doesn’t change much day to day, it’s a function of body composition. Your TDEE swings with what you actually do. Target moves based on your goal. Showing the chain of reasoning makes it obvious where to look when the math feels off. If your “target” looks too aggressive, you can verify it’s because the calculator picked the right activity level, not because the formula is broken.
The cut/maintain/bulk presets use the deltas most coaches recommend: −500 kcal for fat loss (~1 lb per week target), 0 for maintenance, +350 for a lean bulk. Aggressive bulks (+700 or more) tend to put on more fat than muscle and aren’t worth it unless you’re a bodybuilder counting weeks before a show.
About the macros
Protein lands on 1.8g per kilogram of body weight, solid number for anyone training, slightly above the casual recommendation of 1.6g/kg. Fat sits at 25% of total calories, which is enough for hormone health without crowding out the carbs you need to lift heavy or run hard. Carbs fill in whatever’s left.
You can override these manually if your nutritionist prescribed something different, or if you’re on a specific protocol like keto (high fat) or carnivore (low/zero carb). The formula is just a sane starting point.
Activity multipliers explained
- Sedentary (1.2): desk job, no formal workouts, maybe a walk on weekends. Most office workers fall here even if they “feel” busy.
- Lightly active (1.375): 1-3 workouts a week, mostly cardio or light lifting. Or a job that involves walking but not heavy labor.
- Moderately active (1.55): 4-5 workouts a week of meaningful intensity. Most lifters fall here.
- Very active (1.725): daily intense training, often a physical job on top of formal workouts.
- Athlete (1.9): training twice a day, or a job with significant physical labor (construction, farming).
People consistently pick a multiplier one notch above where they actually live. If your weight isn’t moving in the direction you expect after two weeks, drop your activity level by one tier.
Frequently asked questions
Why is my number different from MyFitnessPal? MyFitnessPal often uses Harris, Benedict, which gives slightly higher BMR for the same inputs. Mifflin, St Jeor is more accurate for most modern bodies. A 100-150 kcal gap between calculators is normal.
Should I trust this for medical purposes? No, see a registered dietitian if you have diabetes, an eating disorder history, or are post-surgical. Online calculators give population averages, not individual prescriptions.
My weight isn’t moving on the target. What now? After two weeks of consistent eating, adjust the target by ±200 kcal in the direction you want and reassess. Bodies adapt. Calorie targets need recalibration every 5-10 lbs of weight change.
What about water and fiber? Out of scope here, but a useful baseline: 30-35 ml/kg of water and 14g of fiber per 1,000 kcal eaten.