Fourteen ping pong balls, 1,001 combinations and a 14.0% ceiling: the NBA draft lottery is a probability machine designed to make tanking a bad bet. Here is how it actually works — and what the numbers say.
The machine: how the drawing works
Fourteen numbered balls go into the drum. Four are drawn, and that four-ball combination — order does not matter — maps to one of 1,001 possible outcomes. One thousand of them are assigned to the 14 lottery teams in proportion to their odds; one combination is unassigned and triggers a redraw. The drawing happens off-stage, in a sealed room, before the television reveal.
The odds: flatter than you think
Since the 2019 reform, the three worst teams share identical 14.0% odds at the top pick, and the curve flattens slowly from there. Only the top four picks are drawn; the rest of the order follows inverse regular-season record. That structure produces two important effects: the worst team can fall as far as fifth, and a mid-lottery team jumps into the top four roughly every other year.
The reform did exactly what it was designed to do. Before 2019, the worst record carried a 25% chance at No. 1. The flattening cut the expected value of finishing last — a deliberate strike against tanking incentives, and the math says it worked: the league’s worst team has won the lottery just once since the change.
The history: chaos is the norm
Lottery night routinely ignores the standings. In 2026, Washington converted its position into the No. 1 pick — the franchise’s first top selection since 2010 — in a drawing held May 10 in Chicago. Recent history is full of louder shocks: teams with under 3% odds have walked away with the first pick multiple times since the format changed, which is precisely the volatility the 1,001-combination design encodes.
The full odds table, the combination math and the protected-pick rules are documented at the NBA’s official lottery explainer.
Why it matters in June
The lottery sets the draft’s entire chessboard. Trade-up packages are priced off the odds a team beat, protected picks convey or roll over based on where they land, and the war-room calculus on a franchise player changes completely between picks one and five. Understand the probability machine and the rest of draft season reads like a spreadsheet instead of a soap opera.
