Selling a stock at a loss, but then buying back can cancel the loss? How many days must I wait to claim the loss?

I read something on here about selling a stock at a loss, but then if you buy back in within a certain amount of days, you lose your ability to claim the loss.
How many days do I have to wait after selling at a loss to be able to claim the loss?
Couldn't figure it out with google, because everything was about 'how to claim a loss on tax returns'
Thanks!

Submitted April 05, 2017 at 08:42AM by ghpkhg http://ift.tt/2oIceyU