weight loss calculator
Professional weight loss calculator: estimate BMR, TDEE, safe calorie deficit, weekly loss, and goal-date timeline. Includes formulas, methodology, worked example, and FAQs.
weight loss calculator
Full original guide (expanded)
Plan a realistic, safe weight‑loss path. Enter your stats to estimate BMR and TDEE, select your target (weekly loss or goal date/weight), and get a daily calorie range with a week‑by‑week projection.
Calculator
Results
BMR
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TDEE
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Calorie target
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Weekly loss (proj.)
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Goal ETA
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Protein (guide)
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Show 16‑week projection
| Week | Weight (kg) | Deficit (kcal/day) |
|---|
Data source & methodology
AuthoritativeDataSource: Mifflin MD, St Jeor ST, et al. "A new predictive equation for resting energy expenditure in healthy individuals." Am J Clin Nutr. 1990;51(2):241‑247. doi:10.1093/ajcn/51.2.241. NIH/NIDDK Body Weight Planner for adaptive dynamics; and USDA/HHS Dietary Guidelines for Americans for safe rates and protein guidance. NIDDK BWP, Mifflin–St Jeor, DGA.
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.
We compute BMR using Mifflin–St Jeor and multiply by an activity factor to estimate TDEE. For weight‑change projections we show a linear model using \(7{,}700\,\text{kcal} \approx 1\,\text{kg}\) of body fat and an adaptive model that modestly tapers the deficit over time (simple dynamic factor), acknowledging real‑world metabolic adaptation.
The formula explained
Mifflin–St Jeor (BMR)
Female: $\text{BMR}=10w+6.25h-5a-161$ Male: $\text{BMR}=10w+6.25h-5a+5$
where $w$ (kg), $h$ (cm), $a$ (years).
TDEE: $\text{TDEE}=\text{BMR}\times AF$ where $AF\in\{1.2,1.375,1.55,1.725,1.9\}$.
Linear weight change: With daily deficit $D$, weekly loss $\Delta w = \dfrac{7D}{7700}$ (kg/week).
Adaptive taper (heuristic): $D_t = D\,\big/\,(1+0.02t)$ with $t$ in weeks.
Glossary of variables
| Symbol/Field | Meaning |
|---|---|
| Sex | Biological sex used by Mifflin–St Jeor. |
| Age | Years; influences BMR. |
| Height (h) | Body height in centimeters. |
| Weight (w) | Current body mass in kg. |
| Activity factor (AF) | Multiplier converting BMR to TDEE. |
| BMR | Basal metabolic rate (kcal/day at rest). |
| TDEE | Estimated maintenance calories (kcal/day). |
| Calorie target | Daily intake to reach goal given chosen rate/date. |
How it works: a step‑by‑step example
Example: Female, 30 years, 175 cm, 80 kg, moderately active. BMR = $10\cdot80 + 6.25\cdot175 - 5\cdot30 - 161 = 1614$ kcal/day. TDEE = $1614\times1.55 \approx 2501$ kcal/day. If the weekly loss goal is 0.5 kg/wk, the required deficit is $\dfrac{7700\cdot0.5}{7} \approx 550$ kcal/day, so calorie target $\approx 2501-550=1951$ kcal/day. Goal ETA for losing 8 kg is roughly 16 weeks with adaptive taper slightly lengthening the timeline.
Frequently asked questions
What deficit should I choose?
Common choices are 300–750 kcal/day depending on current weight, activity, and patience. Larger deficits increase fatigue and risk of lean mass loss.
Why do results differ from smartwatches?
Devices estimate energy with different models and sensor inputs. Use one consistent method for trends and adjust using 2–3 weeks of real weight data.
Do I need higher protein?
For active dieters, 1.6–2.2 g/kg/day is often recommended to preserve lean mass; we display a mid‑range suggestion.
Can I mix goal date and weekly rate?
Yes—pick Target weight by date. We compute the implied weekly rate and calorie target. If it exceeds safe bounds, we flag it.
Why show an adaptive projection?
Human metabolism adapts to energy deficit; the simple taper models that your initial deficit becomes slightly less effective over time.
Formula (LaTeX) + variables + units
Mifflin–St Jeor (BMR) Female: $\text{BMR}=10w+6.25h-5a-161$ Male: $\text{BMR}=10w+6.25h-5a+5$ where $w$ (kg), $h$ (cm), $a$ (years). TDEE: $\text{TDEE}=\text{BMR}\times AF$ where $AF\in\{1.2,1.375,1.55,1.725,1.9\}$. Linear weight change: With daily deficit $D$, weekly loss $\Delta w = \dfrac{7D}{7700}$ (kg/week). Adaptive taper (heuristic): $D_t = D\,\big/\,(1+0.02t)$ with $t$ in weeks.
- No variables provided in audit spec.
- NIDDK BWP — niddk.nih.gov · Accessed 2026-01-19
https://www.niddk.nih.gov/health-information/weight-management/body-weight-planner - Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/ - Health & Fitness — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/health-fitness - Diet & Nutrition — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/subcategories/diet-nutrition - Mifflin–St Jeor — academic.oup.com · Accessed 2026-01-19
https://academic.oup.com/ajcn/article-abstract/51/2/241/4695423 - DGA — dietaryguidelines.gov · Accessed 2026-01-19
https://www.dietaryguidelines.gov/ - Calorie Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/calorie - Protein Intake Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/protein-intake-calculator
Last code update: 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.