Double or nothing, known in the UK as double or quits, is a follow-up bet that either doubles the result of a previous wager or cancels it. The phrase is far older than online casinos and is just as common in friendly bets as at the tables.
Say you bet a friend $10 that you will sink a basketball shot, and miss. You now owe $10, so you offer double or nothing: $20 on the next shot. Make it and you are even; miss it and you are $30 down in total. The same idea works after a win, when the winner risks the profit to double it or walk away with nothing. Many slots and video poker games build this into a gamble feature: after a win, the player can guess a card’s colour to double the prize or lose it.
Gamble features and volatility
A double-up option raises volatility on every win. Check how each game implements it, and whether the rules of your target markets allow it, before enabling it. See also the Martingale system.