50 overs per side. Powerplay restrictions apply. Two new balls used. DLS method for rain interruptions. 10 fielders outside 30-yard circle restrictions vary by phase.
Details
One-Day Internationals are played with 50 overs per side. Each bowler can bowl a maximum of 10 overs. Fielding restrictions apply in three phases: Powerplay 1 (overs 1-10, max 2 fielders outside circle), middle overs (11-40, max 4 outside), and death overs (41-50, max 5 outside).
Two new white balls are used — one from each end — to ensure the ball remains visible and in good condition throughout the innings. This replaced the single ball system in 2012.
If rain interrupts, the DLS method recalculates targets. A minimum of 20 overs per side is required for a result.
Historical Evolution
The first official ODI was played between Australia and England at the MCG on January 5, 1971, after a Test was washed out. The format grew rapidly and the first World Cup was held in 1975.
ODI rules have changed significantly over the decades — from 60-over matches to 50, from white clothing to colored, from one ball to two, and from the old fielding restrictions to the current powerplay system.
Current Rule
50 overs per side, 10 overs max per bowler, 3-phase fielding restrictions, 2 new balls, DLS for rain, 20 overs minimum for result.