Hey dear in one month babies should gain 400 to 700 gms weight normally but in the beginning for 10 days after birth they will loose some weight 10%of birth weight then they will start gaining weight

I agree with everyone.

You bBy will loose its birth weight which is called lowest weight, check it its written in the file. By 20 days your bBy should gain the birth weight.

at starting days after born, babies loose weight dear..after 1 month baby will get atleast 1 kg per month ..depends on health..breastfeed him at every 2 hours..

Well after few days baby will loose some weight.
And then start gaining and it all depends on baby. Understanding Baby Weight Gain
Normal Newborn Baby Weight Gain Trajectory And Milestones