Free Calorie & TDEE Calculator — Daily Calories + Macro Split with AI

What Is TDEE and Why It Is the Foundation of Every Weight Goal

Total Daily Energy Expenditure (TDEE)is the total number of calories your body burns across a full 24-hour period — everything from the energy cost of pumping blood and maintaining body temperature, to the thermogenic effect of digesting food, to the calories burned during deliberate exercise and incidental movement. If you eat exactly your TDEE, your weight stays flat. Eat less, you lose weight. Eat more, you gain. Every evidence-based nutrition plan is, at its core, a negotiation with this one number.

Most calorie trackers and fitness apps skip directly to a target number without explaining how it was derived. That creates a fragile plan: when a plateau arrives — and it always does — users have no framework to diagnose which variable shifted and which dial to adjust. This calculator exposes all four layers — BMR, TDEE maintenance, goal-adjusted calorie target, and macro split— so that each can be recalculated independently when body weight, activity, or goal changes.

The engine is the Mifflin-St Jeor equation, which the American Dietetic Association recommends as the most accurate BMR predictor for the general adult population. The activity multiplier converts resting metabolism into a daily total, and the goal offset converts the total into an actionable target. The whole chain is transparent and reversible — you can work backward from a calorie target to see what assumptions it rests on.

The Mifflin-St Jeor BMR Formula

Basal Metabolic Rate (BMR)is the number of calories your body needs at complete rest — lying still, fasting, in a thermoneutral environment. It represents roughly 60–70% of most people’s TDEE. Every other calorie expenditure stacks on top of this floor.

BMR = (10 × W) + (6.25 × H) − (5 × A) + 5
W = weight in kg · H = height in cm · A = age in years

BMR = (10 × W) + (6.25 × H) − (5 × A) − 161
Identical structure; the constant changes from +5 to −161 to account for average sex-based metabolic differences

The Mifflin-St Jeor equation was validated against indirect calorimetry (the gold-standard measurement of actual oxygen consumption) in the original 1990 study and in the landmark Frankenfield et al. 2005 meta-analysis(Journal of the American Dietetic Association, n = 2,528) that compared it against Harris-Benedict, Owen, and WHO/FAO equations. Mifflin predicted measured BMR within 10% for 82% of non-obese adults and 70% of obese adults — outperforming all competing equations. That paper is what cemented Mifflin-St Jeor as the clinical default.

From BMR to TDEE: The Activity Multiplier

BMR is what you burn at rest. Real daily life adds non-exercise activity (NEAT), the thermogenic effect of food (TEF, roughly 10% of calories), and exercise activity thermogenesis (EAT). The combined multiplier is applied to BMR to produce TDEE. Five standard multipliers cover the adult activity spectrum:

Three Worked Examples

Three realistic individuals, three different goals. Copy any of these into the calculator above to reproduce the full result card and macro split, then experiment with your own numbers.

Why Protein Is Anchored to Bodyweight, Not Calorie Percentage

Most macro templates distribute protein as a percentage of total daily calories — a common structure is 30% protein / 40% carbs / 30% fat. The problem is that protein’s functional role is tied to your body’s lean mass, not to your caloric intake. Cutting calories by 500 kcal while keeping protein at 30% of intake reduces protein by 37.5 g per day — exactly when you need it most to prevent muscle catabolism.

Current evidence supports 1.6–2.2 g of protein per kg of body weight per day for adults engaged in resistance training. The landmark 2017 meta-analysis by Morton et al. in the British Journal of Sports Medicine (n = 1,803 subjects, 49 studies) found that increasing protein intake beyond 1.62 g/kg/day produced no additional gain in fat-free mass in resistance-trained individuals. This calculator uses 1.8 g/kg for maintenance and cutting phases and 2.0 g/kg for gaining phases, landing in the center of the evidence-supported range while preserving a realistic margin for day-to-day adherence.

For a 75-kg adult, 1.8 g/kg = 135 g of protein per day. In practice, that is: a 4-oz chicken breast (35 g) + 200 g Greek yogurt (20 g) + one scoop whey (25 g) + two eggs at breakfast (12 g) + a 4-oz salmon fillet at dinner (34 g) = 126 g. One high-protein snack fills the gap. Protein is the least mysterious macro to hit consistently, but only if the daily target is expressed in grams-per-kg, not as a calorie percentage.

Goal Offsets and the Rate of Change

The 3,500-kcal-per-pound-of-fat rule is a rough approximation based on the energy density of adipose tissue (~7,700 kcal/kg), but it is accurate enough for planning purposes at modest deficits. The calculator applies the following standard offsets:

• Gentle cut (−250 kcal/day):≈0.25 kg (0.5 lb) per week. The most sustainable pace; works indefinitely without meaningful performance or muscle-mass degradation for most people.
• Standard cut (−500 kcal/day):≈0.5 kg (1 lb) per week. The widely recommended maximum for sustained fat loss with adequate protein and resistance training. Endorsed by the American College of Sports Medicine.
• Aggressive cut (−750 kcal/day):≈0.75 kg (1.5 lb) per week. Appropriate for short phases (4–8 weeks) at higher starting body fat percentages (>25% men, >33% women). At lower body fat levels, a 750-kcal deficit consistently produces meaningful muscle loss even with adequate protein.
• Lean bulk (+300 kcal/day):≈0.25 kg per week, with better lean-to-fat accretion ratio than larger surpluses. The preferred approach for trained individuals.
• Standard bulk (+500 kcal/day):≈0.5 kg per week. Faster strength and size gains; more fat accumulation accompanies them.

These rates are starting points. Metabolic adaptation — the reduction in BMR and NEAT that occurs in response to a sustained deficit — is real and measurable. The practical fix is not to chase the formula; it is to measure weekly weight (7-day average), check progress against the expected rate, and adjust calories by ±100 kcal increments until the actual rate matches the goal.

When TDEE Directly Informs a Decision

1. Starting a cut or bulk.The failure mode of most diet plans is beginning with an arbitrary round number (“I’ll eat 1,800 kcal”) rather than a number derived from actual BMR and activity. A calculated TDEE gives you a defensible starting point and, crucially, a paper trail: when the weight trend stalls, you know whether to adjust the activity tier, the calorie total, or the protein anchor.
2. Breaking a weight-loss plateau.Body weight is a component of the Mifflin-St Jeor formula — every kilogram you lose reduces your BMR by roughly 10 kcal. A 500-kcal deficit at 80 kg becomes a 400-kcal deficit at 72 kg if the calorie target is not updated. Re-run the calculator every 5–7 kg of weight change to recalculate from your current baseline.
3. Adjusting for a change in training volume.Adding a second sport, starting a new training block, or recovering from an injury all shift the activity multiplier. A shift from moderate to very active (1.55 → 1.725) increases TDEE by roughly 300 kcal at a typical BMR — enough to create or erase a meaningful deficit if not recalculated.
4. Transitioning between phases.Moving from a cut to maintenance — or from a bulk to a maintenance/cut — is best handled by recalculating TDEE from the current body weight and sitting at that new maintenance number for 4–6 weeks. This “reverse diet” window lets leptin, ghrelin, and thyroid hormones normalize before the next phase begins, which is what separates people who keep their results from people who rebound.

When Mifflin-St Jeor Is Less Accurate

The equation was validated on healthy adults of typical body composition. Three groups where it is known to be less accurate:

• Very lean athletes (sub-10% body fat men, sub-18% women).These individuals carry more lean mass per kilogram of total body weight than the Mifflin validation sample, so the equation under-predicts their BMR. A 85-kg bodybuilder and a 85-kg sedentary office worker get the same Mifflin number despite very different metabolic rates. The Katch-McArdle equation, which inputs fat-free mass directly (BMR = 370 + 21.6 × FFM in kg), is superior for this group but requires a DEXA scan or reliable body-fat measurement first.
• Very obese individuals (BMI ≥ 40). Mifflin accuracy drops to ~70% in this population. Studies suggest it over-predicts BMR in some morbidly obese subjects because a higher proportion of mass is metabolically inactive fat tissue. Clinical dietitians often use measured indirect calorimetry for patients in this range.
• Older adults with significant sarcopenia.Loss of muscle mass after age 65 (3–8% per decade) progressively reduces real BMR while Mifflin’s age-correction term is only linear. An 80-year-old at the same weight as their 40-year-old self typically has lower actual BMR than the formula predicts. The two-week empirical test (eat at the calculated target, measure weekly weight, adjust) remains the most practical calibration regardless of formula accuracy.

Common Mistakes

• Treating the TDEE number as exact.The formula has ±10% individual-level error. Use it as a starting hypothesis, not a mandate. Measure your weight trend over two weeks and adjust ±100 kcal until the trend matches your goal.
• Inflating the activity multiplier.“Moderate” (1.55×) requires 3–5 genuine structured workouts per week. Three 30-minute walks and one gym session is “Light” (1.375×). Overestimating by one tier adds ~300 kcal to the target — enough to eliminate a 500-kcal deficit entirely. When in doubt, go one tier lower.
• Letting protein scale down with calories in a cut. This is the single most reliable way to lose lean mass alongside fat. Protein must stay anchored at 1.8 g/kg regardless of how aggressive the calorie reduction is. Carbs and fat are the flex macros.
• Counting calories but not liquid calories. A daily flat white (250 kcal), two glasses of wine (300 kcal), and a post-workout protein shake with milk (200 kcal) add 750 kcal that many people never log. A single honest week of tracking all liquids typically reveals the gap between reported intake and actual intake.
• Not recalculating after a significant weight change.Lose 8 kg and your BMR has dropped by approximately 80 kcal/day. Keep eating the same original target and the deficit shrinks by 80 kcal. After 10–12 kg of loss, a 500-kcal deficit can silently become a 350-kcal deficit. Re-run the numbers every 5–7 kg.
• Ignoring sleep debt as a diet-breaking variable. Sleep restriction raises circulating ghrelin (the hunger signal) and lowers leptin (the satiety signal), making adherence to any calorie target dramatically harder. Consistently sleeping less than 7 hours also impairs insulin sensitivity and blunts the anabolic response to resistance training. Fixing a 6-hour sleep habit may be a higher-leverage intervention than any macro adjustment. See the sleep calculator if sleep is the upstream variable undermining your plan.
• Skipping resistance training during a deficit.Without progressive resistance training, 25–40% of the weight lost in a calorie deficit comes from muscle tissue. Three sessions of resistance training per week, combined with adequate protein, typically reduces this to 5–15%. The training sessions do not need to add much direct calorie burn — their role is hormonal and structural, not thermodynamic.

TDEE and Nutrition Glossary

Related Tools

TDEE is the calories-in side of body composition. The BMI calculatorgives the weight-range context — where you currently sit relative to the WHO healthy band for your height. The body fat calculator provides the composition signal: what share of your weight is fat versus lean tissue, which determines how aggressive a deficit you can sustain without muscle loss. For days when hunger makes adherence hard, check whether sleep is the upstream variable with the sleep calculator— ghrelin and leptin normalization alone can reduce perceived hunger by 20–25%.