Is "stuff" countable?

[Yourjones]

Hello,

Can I say "I have a lot of stuffs in my backpack", and "There is only one stuff on the table, which is my phone"?

Thanks.

 

[Tdol]

I only use it uncountably.

 

[emsr2d2]

I have a lot of stuff in my backpack.
There isn't a lot of stuff on the table. In fact, there is only one thing - my phone.

As you can see, "stuff" is used uncountably.

 

[JMurray]

Can I say "I have a lot of stuffs in my backpack"…?

not a teacher

You can say, "I have a lot of different stuff in my backpack", if you want to emphasise that you have various types of things.