Question: how long does it take for kittens to gain weight?
Answer: Kitten Weight Gain and Developmental Milestones. Kittens should gain about ½ ounce (14 grams) every day or 4 ounces (113 grams) per week. Weigh them at the same time every day with a kitchen or small postal scale. Lack of weight gain in a 24 hour period is cause for concern.