Enter your details to estimate how long it will take to reach your goal weight based on your calorie intake and activity level.
This calculator estimates your TDEE (Total Daily Energy Expenditure) using the Mifflin-St Jeor equation, then calculates your daily calorie deficit or surplus to estimate weight change timeline. One pound of fat is approximately 3,500 calories (7,700 per kg).
Formula: Daily deficit = TDEE - Daily calories. Days to goal = (Weight to lose x 7700) / Daily deficit.
Weight management is fundamentally about energy balance -- the relationship between calories consumed and calories expended. When you eat fewer calories than your body burns, it taps into stored energy (fat) to make up the difference, resulting in weight loss. Conversely, eating more than you burn leads to weight gain. While this principle is simple, the execution involves understanding your unique metabolic rate, choosing the right calorie target, and sustaining the plan over time.
Your Total Daily Energy Expenditure (TDEE) consists of several components. Basal Metabolic Rate (BMR) accounts for 60-75% of total calories burned and represents the energy your body needs for basic functions like breathing, circulation, and cell repair. The thermic effect of food (TEF) accounts for about 10% -- the energy used to digest and process food. Physical activity accounts for the remaining 15-30%, including both structured exercise and non-exercise activity thermogenesis (NEAT) like fidgeting, walking, and standing.
A safe and sustainable rate of weight loss is generally 0.5-1 kg (1-2 lbs) per week, which requires a daily calorie deficit of 500-1000 calories. Deficits larger than this can lead to muscle loss, nutritional deficiencies, metabolic adaptation (your body lowering its metabolic rate to conserve energy), and are difficult to maintain long-term. This calculator provides a realistic timeline based on your inputs so you can set achievable expectations.
It is important to note that weight loss is rarely perfectly linear. Water retention, hormonal fluctuations, muscle gain from exercise, and digestive contents can cause the scale to fluctuate by 1-3 kg day to day. Focusing on the weekly or monthly trend rather than daily weigh-ins provides a more accurate picture of progress. Many experts recommend weighing yourself at the same time each day and tracking a 7-day moving average.
A deficit of 500 calories below your TDEE will result in approximately 0.5 kg (1 lb) of weight loss per week. Most health professionals recommend not eating below 1,200 calories/day for women or 1,500 for men without medical supervision.
This provides an estimate based on the Mifflin-St Jeor equation, which is accurate to within 10% for most people. Individual metabolism, genetics, body composition, and adherence to the calorie target all affect actual results.
Yes, for most people 0.5-1 kg per week is considered safe and sustainable. Faster rates may lead to muscle loss and nutritional deficiencies. People with more weight to lose can safely lose at a slightly faster rate initially.
As you lose weight, your body requires fewer calories to maintain its smaller mass. Your TDEE decreases, reducing your calorie deficit even if you eat the same amount. This is called metabolic adaptation. Recalculating periodically and adjusting intake or exercise helps overcome plateaus.