Hit frequency. Independent math-model data gives Sweet Bonanza 1000 and 2500 a hit frequency of 1 in 2.33 spins, so about 42.9% of spins return something. Review-site estimates of a 50-55% base-game hit rate circulate widely, but those sources publish no counting methodology and should be read as approximations rather than measurements. Requires official provider confirmation. Note also that "a hit" includes sub-stake returns: a 0.25x cluster on a $2 bet returns $0.50 and is recorded as a win while costing you $1.50.
Bonus frequency. The free spins round triggers approximately once every 450 spins (0.22%) in Sweet Bonanza 1000, and once every 450.57 spins in Sweet Bonanza 2500. These figures come from independent slot-math databases; the provider does not publish trigger frequency in its public game sheets, so the exact denominators require official confirmation. Practically: at 500 spins per hour, an average player triggers the bonus slightly less than once per hour of continuous play.
Big-win frequency. One frequently repeated figure holds that wins of at least 1,000x stake occur roughly once every 261,097 spins. The originating source does not disclose its calculation method, so we flag it as unverified but directionally plausible: it implies a 1,000x event roughly once per 520 hours of play at typical spin speeds.
Max-win probability. For Sweet Bonanza 1000, the probability of reaching the 25,000x ceiling is quoted at about 1 in 71,428,571 spins; for Sweet Bonanza 2500, about 1 in 66,722,269 spins. Reformulated for accuracy: these are figures published by independent review databases derived from math-model documentation, not statements issued by Pragmatic Play in a public certificate. Treat them as best-available estimates. To put 1 in 66.7 million into human terms: at 600 spins per hour, eight hours a day, every day, you would expect one max win roughly every 38 years.
Bigwinboard makes the pointed observation that the original's 21,100x cap "appears not to be achievable", whereas the 1000's 25,000x cap is structurally reachable, because x1,000 multiplier bombs give the math model enough firepower to actually assemble the number. That is the real upgrade in the sequels: not the headline cap, but the multiplier ceiling that makes the cap reachable.