This is another common question from mothers who breastfeed, as they can not easily measure the amount of milk the baby is getting. But try not to worry about that. You baby will tell you when he/she is satisfied, as well as the amount of dirty nappies and passing of urine!
Your baby will feed for at least 10 minutes, during the first few days this may mean him/her taking both breasts. You will be able to tell that it is a good feed as your baby's lower jaw will move steadily with only brief pauses to rest. He/she will feed continuously on their own, at a pace that is comfortable for them. When your baby is full, he/she will release the nipple by itself, fall asleep or be contentedly awake. You should not break the feed, even to change breasts. Generally, when a baby is full, they do not cry after a feed. You may experience a sense of your breasts feeling softer, less tense and more relaxed as a result of the feed.
If you think that your baby is not satisfied after a feed, discuss this with your midwife or health visitor before using formula milk or bottles.
Ref: Ref; Expecting everything you need to know about pregnancy labour and birth 2004.
McGrail A, Metland D