“Smiths” is the plural of the last name “Smith”. “Smith’s” is the singular possessive of the name “Smith”. The plural possessive of the name Smith is Smiths’. The plural possessive is used when we want to talk about something The Smith family own such as “The Smiths’ house”.
The Smiths is the plural of the Smith family name. We use this when we are talking about all the members of the family.
The Smiths are a lovely family.
The Smiths live at the top of the road.
We use “The Smith’s” when we are describing something that is owned by a singular person named Smith.
This is Patti Smith’s guitar.
That is Jade Smith’s house.
The Smiths’ when we are describing something that is owned by a plural group such as the Smith family.
The Smiths’ house is huge!
The Smiths’ car is an Audi.
Smiths or Smith’s for a house sign?
You should write “The Smiths” for a house sign.
There is no need for an apostrophe because you are not saying that this is “the Smiths’ house” but rather “The Smiths live here”.
If you include the word “house” then you should use “The Smiths’ house” if more than one member of the family lives there.
Other Phrases with the Smiths
Here are the correct forms of phrases connected with the last name “Smith”
Welcome to the Smiths
Christmas at the Smiths
The Smiths’ residence
The Smiths’ house