Question: how much can you win in vegas before taxes?
Answer: The IRS doesn't care about jackpots less than $1,200. If you win $1,200 - $4,999: Now you've entered the tax threshold. You must fill out a W-2G form to report your winnings to the feds, but casinos aren't obliged to take out withholdings. It will be up to you to pay the taxes later.