Questions & Answers

It is very hard to go by sizes for babies because it also depends on the brand of clothing. You can usually find on the cardboard tags before you buy it the weight and length for each size for that brand. They do very quite a bit sometimes. And like Lyssa said it also depends on the baby for how long they will be in that size. My son was 8lb 1oz when he was born but dropped to 7lb 4oz before we left the hospital. He was 21 inches long at birth. He wore newborn for about to weeks and by 3 months he was in 9-12 month clothes because he was so long. Almost 26 inches. I learned quick to go by length and weight and not months!

3-6 is generally longer than 3 and 6-9 is longer than 6. It tooooootally depends on the kid how long they can wear each thing. Some babies start off in 0-3 but not newborn, some grow faster than others and are out of 0-3 and into just 3 at 2 months.
My son is very tall and leggy, but not chubby, so he stayed in Newborn for 2 months, 0-3 until about 3 months, then 3 month stuff he wore til around 4 1/2 months. I generally keep out 3 sizes at once, then rotate up a size when the smallest one no longer fits. Like for my daughter I'm pregnant with now I keep newborn, 0-3 and 3 out. When newborns don't fit I'll bring out the 3-6 and so on. Good luck!