This roulette calculator will work out what to bet on next based on the previously spun numbers. Just select. Roulette Calculator calculates probability of the next spin in Roulette. So it is a kind off roulette prediction (not roulette cheating). And you do not need to. Free Download Ultimate Roulette Bet Calculator 1 - Simple utility created to offer the user an educated guess when it comes to roulette betting.