Louis' or Louis's

[jimjamjoo]

I need to get this right! Thank you.

I think either is correct

Louis's - the rule is "s'" when a) it's a plural noun or b) the noun has already got a 'ses' sound in it - so Jesus' not Jesus's, for instance.

Either is correct, but just make sure you stick to the same rule throughout the document.

Are you writing for a particular publisher / using citations and references in any named style?

I'd write Louis's but Lucius' - Hart's Rules / Oxford style. Agree other systems fine with Louis'. It annoys me when people "correct" this kind of thing - consistency matters but either is acceptable.

Thanks all. It's actually my new nephew's name and I'm making him a present with his name on. Appreciate your help!

I bet he'll have a lifetime of conflicting instructions! I think I'd just ask the parents their thoughts, for a baby gift

I think in the US, they only use Louis' but in the UK, either is ok.

I'd ask the parents which they prefer.