NFL and NBA game simulations: how they work

How the simulation plays a game 10,000 times

Each run draws one final margin and one final total for the game. The margin and the total always share an odd or even parity, so every run ends in a real final score.

NFL: the margin comes from a normal curve around the consensus home margin, reweighted by how often each final margin has really happened in the NFL since 2016, so 3 and 7 come up far more often than a smooth curve says and ties almost never. The total works the same way around the consensus total. The curves are fitted only on games played before the one being simulated.

NBA: the same method on the NBA consensus line, with curves as wide as real NBA finals have landed around their closing lines. A tied final is impossible, because NBA games go to overtime, and there are no key-number weights.

The draws are seeded by the game, so the page shows the same numbers every time. Without a posted spread and total, or without enough past games to fit the curves, there is no simulation; nothing is filled in.

Whose number is it? The market's, not KarmaEdge's

Every run is centered on the sportsbooks' consensus line: the median spread and the median total across the books on the board. The simulation shows how the game plays out the way the market has priced it. It is not a KarmaEdge pick, and it is not the KarmaEdge AI projection.

KarmaEdge's own AI game projections are a separate product: the AI Models pages show each projected spread and total next to the posted line. Those projections are not simulations.

• NFL AI predictions →
• College football AI predictions →
• NBA AI predictions →

What the simulation shows

• Win chance: each team's share of the 10,000 simulated games.
• The result: the middle of the 10,000 simulated finals.
• A chart of the final margin across every run, and the most common finals.
• Every spread and total on the board, with how often each side covers or goes over, and the pushes.
• A download of the simulation as two CSV files: the page's numbers and one row per simulated game.

The replay: one example game, not the result

Beside the numbers, the X-Ray plays one simulated game out so you can watch it. NFL games are played snap by snap: every snap is a real NFL play, picked for the down, distance, field position, score and clock and for how both teams have played: one the offense ran or the defense allowed this season, otherwise a league play from this season or last. Each team plays its latest lineup, with this week's injury report. NBA games are played possession by possession from each team's real rates over its last 30 games, newest weighted most (early in a season, many of them are from last season): turnovers, free throws, three-point share, make rates, offensive rebounds and pace, with each player's share of the team's last five games; injuries are not known to the NBA engine.

These play-by-play runs are reweighted to the books' line before a game is picked, and the engines' own win chances never set a number on the page. A replay is labelled the most typical game only when it ends on the middle final; otherwise it is labelled an example game. The underdog's upset and a shootout can be watched too.

When no snap-by-snap NFL game is ready, the replay tells one of the 10,000 runs with each team's own real drives from this season. In every replay the order, the clock and the game itself are simulated; the players drawn on the field and the shot spots on the court are illustrative.

What is free and what needs Premium or Elite

• The Matchup X-Ray needs a free KarmaEdge account; no card is needed.
• Every signed-in member gets the simulation for the next game on the slate.
• Premium and Elite open every game's simulation and its download.

• Compare Premium and Elite →

College football

There is no college football simulation. The Matchup X-Ray and its simulation cover the NFL and the NBA. College football has KarmaEdge AI game projections for spreads and totals on the CFB AI Models page.

• College football AI predictions →