Not sure of you particular variety, but the common callas I've come across did well in 6" pots... in fact I had 3 bulbs in one pot and 2 of them blossomed.
I really should go back to pots for the callas because they are lost in the garden anyways, being so close to the ground and often flopping over.

Thank you. I have 3 bulbs and was hoping to put 2 outside in a 10'' pot and 1 indoors in a 6''. Awesome.

I never thought of callas getting enough sunlight indoors. It will be fun to see how it turns out. :)

:D I will keep you updated. My South facing balcony has a glass door , so it pretty much gets sun all day .
Freak snow storm has completely covered my balcony and every thing is cold and white . :(
Will start my call lilies when it gets warmer here.

Around here we've gotten a 'freak' sunny day on occasion too.
Hopefully we're both enjoying a green and colorful view outside our windows soon. :)