I've been telling people 000 unless bub is very little, but I guess that only applies to Bonds wondersuits.

Angus was 8lb 5oz & wore 000 Bonds, little long in the arms, & 000 nighties & singlets too (Bonds)

Ruth was 7lb 10oz. I thought she wore the same, but back then I used to buy pure cotton only, & she had stuff left from Lola & some borrowed things.

Lola was 8lb 10oz, & I thought she wore 000, but reading above maybe it was 0000 at first.

This time I thought I'll need some 0000 to start with for littler babies, as twins surely will be smaller than my other babies, but reading above it sounds like 5 lb or so needs smaller. Will have to have a look what's around. I think Bonds make a 00000? Target sizes seem consistent with Bonds, but Pumpkin Patch do tend to be very generous. (They last though, I still have some Pumpkin Patch stuff from Lola).