What this calculator does
The Postpartum Weight Loss Calculator estimates how long it may take to return to your goal weight after having a baby, based on a safe, gradual rate of weight loss. It assumes about 0.5 kg per week while breastfeeding and about 0.7 kg per week otherwise. This is general guidance, not medical advice — always check with your doctor, midwife, or a registered dietitian before starting a postpartum weight-loss plan.
How to use it
Enter your current weight and your goal weight in kilograms, then select whether you are breastfeeding. The calculator shows the total weight to lose, the estimated number of weeks and months to reach your goal, and the approximate daily calorie deficit that corresponds to your safe weekly rate.
The formula explained
The core calculation is simple: $$\text{Weeks} = \frac{\text{Current weight} - \text{Goal weight}}{\text{Weekly safe loss}}$$. Because roughly 7,700 kcal is stored in 1 kg of body fat, a 0.5 kg/week loss corresponds to about a 550 kcal/day deficit, and 0.7 kg/week to about 770 kcal/day. While breastfeeding, a smaller deficit is recommended to protect milk supply and energy levels.
Worked example
Suppose you weigh 75 kg, your goal is 65 kg, and you are breastfeeding. You need to lose 10 kg. At 0.5 kg/week that is $$10 \div 0.5 = \mathbf{20 \text{ weeks}},$$ or about 4.6 months, with a daily deficit near 550 kcal.
FAQ
Is it safe to diet while breastfeeding? Most experts suggest waiting until milk supply is established (around 6–8 weeks) and keeping loss gradual (\(\leq 0.5\) kg/week). Adequate calories and hydration are essential.
Why is my estimate slower than expected? Postpartum loss is intentionally conservative to protect recovery and, if applicable, milk supply. Rapid loss is not recommended.
Does this replace professional advice? No. It is an estimate only; individual needs vary with health, activity, sleep, and feeding.
