totalizators

Totalizators, also known as parimutuel betting systems, are a class of wagering where all bets of a single event are pooled. Payouts are determined by the size of the pool and the distribution of bets among outcomes, after deductions such as operator commissions and taxes. Because payouts depend on the bets placed, odds are not fixed at the time of a wager; they are set only after the pool is closed, typically when wagering ends or the event begins. Early bettors influence the final odds, and late wagers can adjust potential returns.

The concept originated in the 19th century and was adopted broadly for horse racing and later for other racing and events. The system can be mechanical, electromechanical, or fully computerized; tote boards at venues display current pools and estimated payouts. In many jurisdictions, parimutuel pools are regulated and integrated with online platforms or simulcast networks. The operator may run a single pool for an event or separate pools by race, class, or distance. The term tote is often used for the operators running such pools, as in The Tote in the United Kingdom and Tote Ireland, though the underlying mechanism remains parimutuel.

Today totalizator systems are still used in many places, particularly at racetracks and regulated betting venues. They compete with fixed-odds bookmakers in some markets, especially online, but remain distinctive because payouts are determined by the aggregate betting pool rather than pre-set odds.