TDEE Calculator for Weight Loss — Convert Maintenance Into a Deficit

What TDEE Represents

Your Total Daily Energy Expenditure (TDEE) is the total amount of energy your body uses in a complete 24-hour period. It combines the energy needed to keep your body running at rest (BMR) with the additional energy burned during digestion, movement, exercise, standing, walking, and all other activity. TDEE is the number that, when matched by calorie intake, leads to stable body weight over time. Every calorie-based goal — intentional loss, maintenance, or intentional gain — starts from this anchor number.

The Two-Part Formula

Understanding the 6 Activity Bands

The six activity bands correspond to the widely cited Mifflin-St Jeor scaling levels. Sedentary (1.2) describes a largely seated day with no structured exercise and limited walking. Lightly Active (1.375) adds 1–3 days of light exercise or daily walking and steps over roughly 5,000–7,000. Moderately Active (1.55) corresponds to 3–5 days per week of structured exercise — a common baseline for many regular gym-goers and active commuters. Active (1.725) implies 6–7 days of exercise or a job that keeps you on your feet most of the day. Very Active (1.9) combines daily hard training with a physical role or frequent movement, and Athlete (2.0) reflects elite volume, often two daily sessions.

How the Rate Grid Is Built

From your maintenance TDEE, the eight-card grid applies standard weekly rate adjustments. Each pound per week of weight change is converted to per-day calorie shifts using the 3,500 kcal/lb convention: 0.25 lb/week ≈ ±125 kcal/day, 0.5 lb/week ≈ ±250 kcal/day, 1.0 lb/week ≈ ±500 kcal/day, 1.5 lb/week ≈ ±750 kcal/day, and 2.0 lb/week ≈ −1,000 kcal/day (loss-side only). Gain-side rates are capped at 0.5 lb/week in the default grid because faster gains tend to disproportionately increase fat storage rather than lean tissue for most natural non-elite trainees.

Why Prefill via ?bmr=

The optional URL prefill from the BMR Calculator lets you compare formulas on the BMR page, pick the one that best matches your context (for example, using Katch-McArdle if you know body composition), and then carry that specific BMR value forward to the TDEE page. In prefill mode, gender / age / height / weight inputs still update on-screen BMR for reference, but the core TDEE anchor comes from the URL value you brought in. This gives you flexibility to work with your own BMR estimate, indirect calorimetry reading, or wearable-device estimate of daily burn.

Known Limitations of TDEE Math

Population-level equations miss individual variation. Muscle mass, genetics, thyroid function, hormonal cycles, caffeine and stimulant intake, sleep quality, gut absorption, Rx items, body composition adaptations, and even minor unplanned fidgeting can shift real daily burn by hundreds of calories in either direction. The calculator is a reference starting point, not a measured truth. Validating against 2–3 weeks of actual weight data while tracking intake is the most reliable way to refine the number for your unique body.

Why TDEE Is the Right Starting Point for Weight Loss

Total Daily Energy Expenditure (TDEE) is the number of calories your body burns in a typical day, accounting for basal metabolism, activity, the thermic effect of food, and adaptive thermogenesis. TDEE equals your maintenance level — the intake at which body weight stays stable. To lose weight, you subtract a controlled daily deficit from TDEE. The advantage of starting from TDEE rather than a generic calorie chart is that TDEE reflects your actual body size, age, sex, and activity level, producing a personalized deficit that matches your real energy budget. A deficit that works for a sedentary 60 kg woman will not work for an active 90 kg man, and vice versa.

From TDEE to Weight Loss Target

The chain from TDEE to weight loss is simple: subtract a controlled deficit. A daily deficit of 500 kcal tends to produce roughly 0.5 kg (about 1 pound) of scale weight loss per week. A deficit of 1000 kcal tends to produce roughly 1 kg (about 2 pounds) per week. Most adults do best with a 500 to 700 kcal daily deficit, which balances rate of loss with muscle preservation and adherence. Aggressive deficits above 700 to 1000 kcal per day should be reserved for higher starting weights and used with close monitoring. A practical floor for most adults is to never eat below 1200 kcal per day for women or 1500 kcal per day for men without qualified supervision.

Protein and Training During the Cut

During a TDEE-based deficit, your body breaks down both fat and lean tissue for energy. To tilt the balance toward fat loss and preserve muscle, prioritize protein intake and resistance training. A practical baseline is roughly 1.6 to 2.2 grams of protein per kilogram of body weight per day, spread across 3 to 4 meals. Add two strength sessions per week using bodyweight, dumbbells, resistance bands, or machines. Muscle is metabolically active tissue and supports long-term weight stability; preserving it during a fat-loss phase makes maintenance far easier afterwards. Endurance athletes in a cut should keep carbohydrate around training sessions and never drop below 3 g/kg/day or performance suffers.

Handling Weight Loss Plateaus

Weight loss plateaus are common after 4 to 8 weeks on a fixed deficit. As you lose weight, your BMR drops because there is less body mass to maintain; the same calorie target that produced a 500 kcal deficit initially may now only produce a 300 kcal deficit. Subconscious reductions in non-exercise activity (fidgeting, walking, taking stairs) also occur as the body adapts to lower intake. Water shifts can mask fat loss for 1 to 3 weeks at a time. To restart progress, recalculate TDEE with your new weight, slightly increase activity (10 to 15 minutes of daily walking is highly effective), or reduce calories by 100 to 200 per day. Avoid the temptation to slash calories further — small adjustments based on observed trend work better than dramatic cuts.

Practical Tracking Tips

• Weigh yourself 3 mornings per week under consistent conditions and use the weekly average. Daily readings are noisy due to hydration, sodium, and digestive contents.
• Re-calculate TDEE every 4 to 8 weeks as body weight shifts. As weight drops, TDEE drops too, and the original deficit stops producing results.
• Track daily steps as a simple proxy for spontaneous activity. Aim for 7000 to 10000 steps per day to support the deficit without added cardio.
• Pair scale weight with waist circumference, progress photos, and how your clothes fit. Fat loss often shows in these markers before the scale moves.
• Sleep 7 to 9 hours per night. Chronic sleep disruption alters hunger hormones and undermines adherence to any deficit.