Weight Loss Calculator
Plan weight loss from your TDEE and target weight: daily calorie target, weekly deficit and the weeks to your goal.
Your goal weight — must be below your current weight.
0.25-1 kg per week is a sustainable, commonly recommended pace.
Daily calories to reach target
2,345 kcal
TDEE 2,895 − deficit 550 kcal
Estimated time to goal
20 weeks
≈ 140 days at 0.5 kg/week
Total to lose
10 kg
7,700 kcal per kg
Calorie-balance model using the Mifflin-St Jeor equation. Estimates only — real losses vary with adherence, muscle changes and metabolic adaptation. Talk to a doctor before starting any weight-loss plan.
Weight Loss Calculator on True Calculator gives you an instant, accurate answer with no sign-up and no app install. Plan weight loss from your TDEE and target weight: daily calorie target, weekly deficit and the weeks to your goal. Every result shows the formula and a worked example so you can verify the calculation yourself, and all values are computed in your own browser — your numbers never leave your device.
Popular uses: weight loss calculator · calorie deficit calculator · weight loss timeline
Reviewed by the True Calculator team · Last updated: August 2026
How We Calculate
This calculator uses medically reviewed formulas verified by our team. All calculations are performed instantly in your browser using JavaScript — no data is sent to any server.
We use WHO-recommended formulas and medical standards for health calculations. Results are estimates, not medical advice — always consult a doctor for health decisions.
When to Use This Calculator
The weight loss calculator turns the calorie-balance model into a personal plan: a daily target, a deficit and a realistic horizon. People preparing for events, weddings or medical targets use it to see whether their goal is achievable at a healthy pace or needs more time. Those starting a fitness programme use it alongside the protein and macro calculators to make sure the deficit does not cost them muscle. Dietitians and trainers use the timeline to set expectations and recheck points, since the model assumes steady adherence. Because the tool refuses targets below 1,000 kcal, it quietly steers extreme dieters toward a safer pace. Like all estimates it assumes the activity factor is honest — over-reporting activity is the most common reason real results lag the plan, so most users learn to trust the scale trend over several weeks.
How to Use This Calculator
- Step 1: Select your sex and enter your current weight, height and age.
- Step 2: Choose the activity level closest to your typical week.
- Step 3: Enter a target weight below your current weight and a weekly loss rate between 0.25 and 1 kg.
- Step 4: Read your daily calorie target, weekly deficit, total weight to lose and the estimated timeline to goal.
Worked Example
A moderately active 30-year-old man weighing 90 kg at 178 cm has a Mifflin-St Jeor BMR of about 1,868 kcal, giving a TDEE of about 2,895 kcal at the 1.55 factor. Targeting 80 kg at 0.5 kg per week means a deficit of 550 kcal a day — 3,850 kcal a week, since 1 kg of body fat holds about 7,700 kcal. His daily target is therefore about 2,345 kcal. With 10 kg to lose, the plan estimates roughly 140 days, or about 20 weeks, to reach the goal at the planned pace.
Tips and Common Mistakes
- •Tip 1: Aim for 0.5-1 kg per week — faster rates usually shed water and muscle, not fat.
- •Tip 2: Eat 1.6-2.2 g of protein per kg of body weight to protect muscle during the deficit.
- •Tip 3: Recalculate every 3-4 kg lost, since TDEE falls as you shrink.
- ✗Mistake 1: Drastically cutting below the suggested target; very low intakes invite muscle loss and rebound hunger.
- ✗Mistake 2: Chasing the timeline too literally — plateaus are normal, so judge progress on weekly averages.
Frequently Asked Questions
How is my daily calorie target calculated?
The calculator estimates BMR with the Mifflin-St Jeor equation, multiplies it by your activity factor to get TDEE, then subtracts the deficit implied by your weekly loss rate — about 550 kcal per day for 0.5 kg per week, since 1 kg of body fat holds roughly 7,700 kcal.
Is 0.5 kg per week a safe rate of weight loss?
Yes — 0.5-1 kg per week is the commonly recommended sustainable range for most adults. Faster loss often comes from water and muscle rather than fat, and sharply restricted diets are harder to maintain and more likely to rebound.
Why do I need to eat more than 1,000 kcal even when dieting?
Very low intakes risk muscle loss, nutrient deficiencies and a slowing metabolism. The calculator refuses targets below 1,000 kcal — if your numbers go that low, a slower loss rate or a modest increase in activity is the healthier adjustment.
How accurate is the estimated timeline to my goal?
The timeline assumes the deficit is achieved every day and that all weight lost is fat, which is never perfectly true. Plateaus, water shifts and metabolic adaptation mean real timelines run longer — treat the estimate as a minimum, not a promise.
Should I focus only on calories, or also on what I eat?
Calories set the direction, but food quality decides how you feel while losing. A higher-protein, fibre-rich diet preserves muscle, keeps you full and protects micronutrients. Losing weight on empty calories leaves you hungry and prone to quitting.
When should I see a doctor before dieting?
If you have diabetes, heart or kidney disease, are pregnant or nursing, take regular medication, or plan to lose a large amount of weight, check with a doctor first. The same applies if you are under 18 or have a history of disordered eating.
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