My husband and I can’t agree on a nickname for our daughter who is due in [name_u]July[/name_u]. We love the name [name_f]Mercedes[/name_f]. We would call her [name_f]Mercedes[/name_f] at home and on occasion but for the most part we want to use a nickname, so each of us calling her something different does not solve the problem! He wants family, friends and teachers to call her [name_f]Mercy[/name_f] and I want her to go by [name_f]Sadie[/name_f]. I’m willing to compromise but I don’t know how I feel about [name_f]Mercy[/name_f]. What do you think of [name_f]Mercedes[/name_f] nicknamed [name_f]Mercy[/name_f]?
I have to admit neither nickname seemed obvious until I kept reading. I was thinking the nickname would just need to be M (emm)
I much prefer [name_f]Sadie[/name_f] over [name_f]Mercy[/name_f]. Much much much!
But neither was immediately obvious, so unless she was introduced thst way and used that name all the time, i dont think itd be a natural nickname
[name_f]Mercy[/name_f] seems a lot more intuitive than [name_f]Sadie[/name_f] to me. If I were picking between the nicknames on their own I would choose [name_f]Sadie[/name_f], but it seems like a stretch from [name_f]Mercedes[/name_f] to me, and I tend not to like stretch nicknames. [name_f]Mercy[/name_f] is pretty cute I think.
[name_f]Sadie[/name_f] is by far my preferred nickname. [name_f]Mercy[/name_f] is a word name with a very strong heavy meaning, and I think the lighter, brighter [name_f]Sadie[/name_f] is much better suited to a little girl.
Both nicknames make sense to me. I think I prefer [name_f]Sadie[/name_f] over [name_f]Mercy[/name_f]. Maybe you could wait till she’s born to see which one you think suits her better. [name_m]Even[/name_m] if you pick [name_f]Mercy[/name_f] though, it’s not like you can’t call her [name_f]Sadie[/name_f], and when she gets older she might decide she prefers whichever nickname you don’t choose to use primarily. So I think it’s okay to take your time deciding on her nickname and getting a sense for what feels more fitting for your [name_f]Mercedes[/name_f].
I don’t see why you can’t use both, honestly. I grew up with 3 different nicknames (given to me by various family members) and it’s never been confusing to me.
But, if you want to use just one, I much prefer [name_f]Sadie[/name_f]. 
[name_m]How[/name_m] about [name_f]Merry[/name_f] or [name_u]Desi[/name_u]?
I think both [name_f]Mercy[/name_f] and [name_f]Sadie[/name_f] work well for [name_f]Mercedes[/name_f]. I agree with 2 pps: why not wait til she’s born and see which nickname develops naturally and seems to suit her? Also I see nothing wrong with having 2 (or more) nicknames. A little one in my life has 3 different nicknames used in the family and also uses her full name. It’s all easy, cute and fun!
Our top girls name is [name_f]Mercedes[/name_f], and our nn is [name_f]Mercie[/name_f]. I think using “ie” looks nicer than “y”, and more nicknamey. 
This is a really good point.
I had multiple nn’s (and still do) - most people call me [name_u]Kay[/name_u]; my Dad calls me [name_u]Red[/name_u]; my Mum calls me [name_f]Karri[/name_f]; my baby sis calls me Kaybee or Kazzy…
I don’t feel confused or annoyed by it. In fact, I think it’s cute that each person shows their connection in a different way. And the nn’s that get used specifically by one person end up being even more special.