luckadjusted
NFL Week 9 · 2026

Week 17 2025 · December 25, 2025

Broncos at Chiefs, Week 17 2025: who deserved to win?

The Broncos beat the Chiefs 20–13, but the replays call it close to a coin flip: with the way both teams played, the Broncos win 6 of 10. Luck ran their way: injuries alone were worth 13 points of win probability to the Broncos.

Before kickoff the Broncos were 84% favorites. The biggest swing (Q4, 5:52 left): the Broncos converted 3rd & 10, worth 15 points of win probability to the Broncos.

Final

Denver Broncos 20
Kansas City Chiefs 13

December 25, 2025 · GEHA Field at Arrowhead Stadium · Closing line: Broncos −13.5

Luck index +41 Broncos lucky · −41 Chiefs

Each team’s own plays from this game, resampled into new drives 4,000 times: with the way both teams actually played, how often does this performance win? How the replay works

Ten replays. Broncos win 6, Chiefs win 4.

  1. 1 DEN 26 KC 7
  2. 2 DEN 28 KC 14
  3. 3 DEN 34 KC 24
  4. 4 DEN 27 KC 20
  5. 5 DEN 21 KC 17
  6. 6 DEN 23 KC 21
  7. 7 DEN 10 KC 13
  8. 8 DEN 17 KC 23
  9. 9 DEN 13 KC 23
  10. 10 DEN 10 KC 27

Three other ways to ask

Each answers a different question, so none of them replaces the replay above.

The closing betting line, turned into a probability. What everyone knew before the game.

The line plus what this game showed, weighted by how much one game can tell. It stays close to the line because one game says little.

Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.

How 4,000 replays ended

Broncos win 59% of them, Chiefs 41%, counting the 3% still level after regulation as half each. The line is what actually happened: Broncos by 7.

Show as a table
Final margin in the replaysShare of replays
Broncos by 17+9.6%
Broncos by 9–1616.7%
Broncos by 1–833.0%
Level after regulation3.1%
Chiefs by 1–821.8%
Chiefs by 9–1612.1%
Chiefs by 17+3.7%

Where the luck was

What the luck was worth

Every lucky and unlucky play, weighted by the moment it happened: its swing in win probability, added up by kind. A missed kick in a decided game counts for nothing; the same kick at the end of a tie game can be most of a win.

Swings add up across a game, so in one that went back and forth they can pass 100%. On the scoreboard the same luck was worth +4.5 points to the Broncos: the final margin was Broncos by 7, without the luck Broncos by 2.5. Luck shares are the fitted ones (how much of each kind is luck).

The kicks

How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.

  • W. Lutz, 27 yds made · 96% expected
  • W. Lutz, 30 yds made · 95% expected
  • H. Butker, 53 yds made · 70% expected
  • H. Butker, 47 yds made · 80% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Broncos 5 for 57 yards, Chiefs 2 for 10 yards

Every accepted flag, in order, and what it did to the helped team’s chance of winning at that moment, including any play it wiped out (points on the scoreboard in grey). A flag in a decided game is worth nothing; one at the turn of a close game can be worth most of a win. Judgment calls count half toward luck; pre-snap fouls, which repeat, don’t count. How calls are valued

WhenFlagWin probability for
Q2 8:33 Offensive Holding on the Broncos (Kris Abrams-Draine), 10 yards +1% KC +0.9 pts
Q2 3:38 False Start on the Broncos, 5 yards · pre-snap +4% KC +0.5 pts
Q3 13:23 Defensive Pass Interference on the Broncos (Patrick Surtain II), 27 yards +4% KC +1.6 pts
Q3 8:02 Offensive Pass Interference on the Broncos (Evan Engram), 10 yards, wiping out the play +13% KC +2.2 pts
Q3 1:09 Neutral Zone Infraction on the Broncos (Nik Bonitto), 5 yards · pre-snap +2% KC +0.3 pts
Q4 2:00 Neutral Zone Infraction on the Chiefs (Chris Jones), 5 yards · pre-snap +12% DEN +1.6 pts
Q4 0:25 Delay of Game on the Chiefs, 5 yards · pre-snap +5% DEN +0.6 pts

Broncos penalties, every game · Chiefs penalties, every game · All teams, 2025

When it happened

Chiefs’ chance of winning

As low as 0% and as high as 75%. Numbers mark the biggest luck moments, listed below.

nflfastR’s in-game win probability. It ignores the betting line, so it starts near even. Shaded above the middle while the Chiefs were ahead in it, below while the Broncos were.
#WhenWhat happenedWin probability forNext drive
1 Q2 12:56 The Chiefs converted 3rd & 53rd & 4th downs · 33% expected +7% KC KC: Touchdown
2 Q3 8:47 The Broncos converted 3rd & 33rd & 4th downs · 54% expected +7% DEN DEN: Touchdown
3 Q3 8:02 Offensive Pass Interference on the Broncos (Evan Engram), 10 yards, wiping out the playJudgment calls · 12 flags in 4740 snaps before, position avg 1 per 278 +13% KC KC: Punt
4 Q4 12:00 The Broncos were stopped on 3rd & 43rd & 4th downs · 48% expected +8% KC DEN: Punt
5 Q4 8:08 H. Butker made a 47-yard field goalKicks · 80% expected for him, 54 of 73 from 45+ before +7% KC KC: Turnover on downs
6 Q4 5:52 The Broncos converted 3rd & 103rd & 4th downs · 30% expected +15% DEN DEN: Touchdown
7 Q4 2:00 Neutral Zone Infraction on the Chiefs (Chris Jones), 5 yardsPre-snap flags · 42 flags in 6089 snaps before, position avg 1 per 323 +12% DEN DEN: Touchdown
8 Q4 0:25 The Chiefs were stopped on 3rd & 83rd & 4th downs · 32% expectedDelay of Game on the Chiefs, 5 yardsPre-snap flags +9% DEN KC: Turnover on downs

Missing players

Key players (usually on the field for half the snaps or more) who missed this game or part of it, valued by position and quality. The same players are missing in every replay, so this counts as luck in points only.

  • Patrick Mahomes (KC QB), out (IR), replaced by c.oladokun · 7.1 pts
  • Trent McDuffie (KC CB), out (IR) · 1.4 pts
  • Jawaan Taylor (KC T), out (IR) · 0.9 pts
  • Josh Simmons (KC T), out (IR) · 0.7 pts
  • Rashee Rice (KC WR), out (IR) · 0.7 pts
  • Jaylen Watson (KC CB), out (IR) · 0.6 pts
  • Leo Chenal (KC LB), out (IR) · 0.2 pts
  • Jaylon Moore (KC OL), out · 0.1 pts
  • Brandon Jones (DEN S), out (IR) · 0.4 pts
  • Luke Wattenberg (DEN C), out (IR) · 0.3 pts
  • Pat Bryant (DEN WR), out · 0.3 pts
  • Dre Greenlaw (DEN LB), out · 0.2 pts
  • J.K. Dobbins (DEN RB), out (IR) · 0.2 pts

Adjust the assumptions

Disagree with how much of a fumble bounce or a pass interference call is luck? Change it and the coin-flip replay reruns in your browser.

Only coin-flips re-rolled

Broncos 98% · Chiefs 2%

Final margin
Broncos by 7
Luck in points
4.5 for the Broncos
Luck-adjusted margin
Broncos by 2.5
Replay with same day's form
Broncos 59% · Chiefs 41% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

None by default: our tests measured no carryover after a lucky break. Slide it up to count a break for more than its own swing. Why

Flip a play

Force the other outcome, in this game and in every replay: a made kick becomes a miss, a stop becomes a conversion, a flag goes the other way.

About these numbers

Play-by-play and win probability from nflfastR via nflverse; kicks valued against each kicker’s own record; drops and interception-worthy throws from FTN charting; injuries from snap counts and injury reports.

Methodology and validation · All Week 17 2025 games · Broncos · Chiefs

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