im not sure there is a limit other than how much memory your phone has at the time your adding the contacts. i see ppl saying they heard of people adding 1200.
i run a business and i decided i wanted to add everyone to my business phone, ive only tried one run at this and i managed to upload 5000 contacts at once....... im aiming to upload 44'000 lol, but thought id do in small steps... the iPhone accepted the 5000 contacts, but it was more problematic than i imagined..
them being on your phone is no problem, it was more the process in which to add..... one site tells you to add a Vcard to upload, others say CSV.....
i tried uploading via itunes also without success..
in the end, i got my 5000 contacts, added them to my outlook contact book. next i used the icloud desktop app and told it to sync my outlook address book with my icloud. it then sync all the contacts into my icloud account. from here i just plugged the iPhone into my pc and clicked the sync button. JOB DONE......... bit of a messy process for something that's quite simple lol, but that's apple for you...
so to summarise:
1. create csv of your contacts
2. upload csv to outlook address book
3. download icloud desktop app
4 once you have all teh contacts in outlook, simply click sync button on icloud desktop app and itll copy all teh contacts across to icloud.
5. once in icloud, simply sync your phone with your pc.
make sure your iphone settings are set to use icloud and you have input the credentials via your phone settings.
to summarise, i believe the amount of contacts is based on your phones disk space..... i have 5000 so far and it dosent make a dent on my iphone 5 16gb
ill let you know if i maek the 44'000 mark lol... i work on that later now i know i can upload 5000