Grandad or Granddad?

[LoopyLoops]

Making Christmas mugs, mind has gone blank... is it Grandad or Granddad?

Granddad

I think.

the first-well that's what i did!

I think you can actually use either.

Granddad makes more sense, but Grandad looks better. More tidy. Heh.

Grandad

oxford dictionary says first, but either acceptable

Grandad

I think it should be Granddad, but everyone I know spells it Grandad.

Grandpa