How long will this tattoo take to complete?

On average, a guesstimate.

http://www.tattooartists.org/Img223440_Cross_-_forearm.asp

Sent from my iPhone

3- maybe 5 hour depending on how well you want it done and if you add more to it

In all honesty, I would agree with maybe 4-5 hours. But the only way to know is ask your artist… Only they will know how fast they work.