Daily Calorie Target
{{ format(dailyCalories) }} kcal
BMR {{ format(bmr) }} TDEE {{ format(tdee) }} {{ format(deficit) }} Deficit

Daily calorie target: {{ format(dailyCalories) }} kcal
(TDEE {{ format(tdee) }} − deficit {{ format(deficit) }})

You need an average deficit of {{ format(deficit) }} kcal / day to lose {{ format(totalLoss) }} {{ weightUnit }} in {{ timeframeValue }} {{ timeframeUnit }}.

Target weekly loss: {{ format(weeklyLoss) }} {{ weightUnit }}

Week Weight ({{ weightUnit }}) Loss-to-date TDEE Cal Target
{{ r.week }} {{ formatDec(r.weight) }} {{ formatDec(r.loss) }} {{ format(r.tdee) }} {{ format(r.cal) }}
Categories: Calculator , Health & Fitness
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Energy balance governs body-weight change: when daily intake stays below expenditure, stored tissue supplies the shortfall and mass declines. Basal metabolic rate (BMR) expresses resting needs, while total daily energy expenditure (TDEE) layers activity on top, creating a personalised maintenance threshold.

This calculator applies the Mifflin–St Jeor equation to your age, sex, height and weight, scales it by an activity factor, then subtracts the energy required to shed the chosen kilograms or pounds within your timeframe. The result is a clear daily calorie target and week-by-week schedule rendered by a reactive engine and charting layer.

For example, trimming five kilograms in twelve weeks at a moderate activity level yields roughly a 500 kcal daily deficit and a 0.4 kg weekly loss. This calculator offers informational estimates, not medical advice.

Technical Details:

Weight change obeys the first law of thermodynamics: energy cannot be created or destroyed, only converted. The Mifflin–St Jeor equation estimates BMR from mass, stature and age, then multiplies it by an empirically derived activity factor to predict TDEE. By translating desired weight loss into a caloric deficit (7 700 kcal ≈ 1 kg fat), the tool pinpoints an actionable intake ceiling.

BMR=10W+6.25H−5A+S TDEE=BMR×Factivity Calorie Target=TDEE− ΔWt×7700
Activity CodeFactor (Factivity)Description
Sedentary1.2Little or no structured exercise
Light1.3751–3 training days per week
Moderate1.553–5 training days per week
Active1.7256–7 training days per week
Extra1.9Physical labour or twice-daily training

Choose the row that best matches routine exertion; over-estimating lifts the target and slows progress.

  • W – current body mass (kg).
  • H – height (cm).
  • A – age (years).
  • S – +5 for male, −161 for female.
  • ΔW / t – desired weekly loss (kg · wk−1).
  • Energy cost of fat loss averaged at 7 700 kcal kg−1.
  • Lean mass changes and adaptive thermogenesis are ignored.
  • Activity factor assumes stable training volume.
  • Very low targets (<1 200 kcal) may impair nutrient sufficiency.
  • Growth, pregnancy or illness alters metabolic rate unpredictably.
  • Rapid loss goals (>1 % body weight per week) exceed safe deficit capacity.
  • Weight unit mismatch skews BMR by 2–3 ×.
  • Height inputs <100 cm or >250 cm fall outside validation range.

Formulas derived from Mifflin et al. (1990) and supported by subsequent validation studies; activity multipliers adapted from FAO/WHO/UNU expert reports; 7 700 kcal per kilogram approximates energy density of adipose tissue.

This offline computation handles personal metrics in-browser and is not subject to HIPAA, though GDPR applies to any stored records.

Step-by-Step Guide:

Follow these steps to convert your goal into a daily calorie ceiling.

  1. Enter Age, biological sex, height and current weight.
  2. Select the unit (kg / lb) matching your scale.
  3. Set a realistic goal weight and timeframe—longer windows demand smaller deficits.
  4. Pick the activity level that mirrors weekly movement.
  5. Read the summary badge; switch tabs to inspect projected weight curve, weekly calories and downloadable schedule.

FAQ:

Which formula powers the calculation?

The tool uses the Mifflin–St Jeor equation for BMR and multiplies it by an activity factor drawn from nutritional research.

Is the recommended deficit safe?

Targets stay within 0.25–1 % body-weight loss per week, generally considered safe for healthy adults; consult a clinician if unsure.

Can I change units later?

Yes. Switching between kilograms and pounds instantly recalculates every figure through the reactive engine.

Is my data stored?

No. All numbers remain in your browser; closing the tab erases them automatically.

Why does BMR differ from other sites?

Alternative calculators may use Harris–Benedict or Katch–McArdle equations, and their activity multipliers can vary.

Glossary:

Basal Metabolic Rate (BMR)
Energy used at rest in a thermoneutral state.
Total Daily Energy Expenditure (TDEE)
BMR multiplied by habitual activity factor.
Calorie Deficit
Difference between TDEE and actual intake.
Activity Factor
Multiplier reflecting exercise and occupation level.
Mifflin–St Jeor Equation
Empirical formula predicting BMR from weight, height, age and sex.