Every NBA Draft Lottery Rule Change, From 1966 Coin Flips to the 2027 3-2-1 Overhaul

Weighted Lottery (1990)

In 1990, the NBA introduced its first system that differentiated odds based on record. A pool of 66 ping-pong balls was used. The worst team received 11 balls, giving it a 16.7% chance at the No. 1 pick, the second-worst received 10, and the odds decreased incrementally down to a single ball for the best lottery team . This was the first attempt to give the truly bad teams a slight edge without guaranteeing them a top pick.

1994 Odds Revision

Approved in November 1993, this reform steepened the weighting significantly. The league switched to a format using 14 ping-pong balls numbered 1 through 14, and the four-number combination system that remains in spirit today. The worst team saw its odds of winning the No. 1 pick jump from 16.7% to 25%, while the best lottery team's odds plummeted from 1.5% to 0.5% . This core structure remained largely intact through expansion cycles and into the 2010s.

2019 Odds Flattening

In response to the Philadelphia 76ers' brazen multi-year "Process" tanking strategy, the NBA flattened the odds dramatically starting with the 2019 draft. The bottom three teams were each given an equal 14% chance at the No. 1 pick, a steep drop from the previous 25% for the worst team. The lottery also began determining the first four picks instead of just the first three, further reducing the penalty for being the league's worst team .

The 3-2-1 Lottery (Effective 2027 Draft)

On May 28, 2026, the NBA Board of Governors passed the most radical anti-tanking measure in league history by a 29-1 vote . The new system, termed the 3-2-1 Lottery, will take effect with the 2027 NBA Draft and represents a complete philosophical reversal from the previous 25% era. The key changes are:

• Expansion to 16 teams — The lottery no longer includes only non-playoff teams. It now encompasses the 10 teams that miss the play-in tournament, the four No. 9 and No. 10 play-in seeds, and the losers of the No. 7 vs. No. 8 play-in games .
• The Relegation Zone — The bottom three teams are now penalized with a "relegation zone" and receive worse odds than better teams. Each of the three worst teams will have only a 5.4% chance of winning the No. 1 pick .
• Flattened Odds for the Middle Tier — Teams that finish with the fourth-worst record through the tenth-worst record will all have an equal 8.1% chance at the top pick .
• Play-in Losers — The losers of the 7/8 play-in games will have a 2.7% chance at the No. 1 pick .
• Ball Allocation — As the name implies, each lottery team receives three, two, or one ping-pong balls based on its tier, rather than a complex combination system, simplifying the draw and ensuring no team has an outsized mathematical advantage .

The league's explicit goal with the 3-2-1 system is to eliminate the incentive for any team to prioritize its draft position over winning games. For the first time in history, finishing with one of the very worst records is a significant mathematical disadvantage rather than an advantage .