luckadjusted

Week 18 2025 · January 3, 2026

Seahawks at 49ers, Week 18 2025: who deserved to win?

The Seahawks beat the 49ers 13–3, but it was a coin flip: replayed with the way both teams played, the Seahawks win 4 of 10. Luck ran their way: 3rd & 4th downs alone were worth 3.4 points to the Seahawks.

Before kickoff the Seahawks were 57% favorites. The biggest swing (Q4, 10:27 left): the 49ers were intercepted on a well-placed throw, worth 12 points of win probability to the Seahawks.

Final

Seattle Seahawks 13
San Francisco 49ers 3

January 3, 2026 · Levi's Stadium · Closing line: Seahawks −2.5

Luck index +55 Seahawks lucky · −55 49ers

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. Seahawks win 4, 49ers win 6.

  1. 1 SEA 29 SF 13
  2. 2 SEA 16 SF 7
  3. 3 SEA 29 SF 24
  4. 4 SEA 19 SF 17
  5. 5 SEA 14 SF 16
  6. 6 SEA 19 SF 24
  7. 7 SEA 6 SF 14
  8. 8 SEA 3 SF 13
  9. 9 SEA 10 SF 25
  10. 10 SEA 6 SF 28

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

Seahawks win 45% of them, 49ers 55%, counting the 7% still level after regulation as half each. The line is what actually happened: Seahawks by 10.

Show as a table
Final margin in the replaysShare of replays
Seahawks by 17+7.2%
Seahawks by 9–1612.4%
Seahawks by 1–823.8%
Level after regulation7.2%
49ers by 1–824.8%
49ers by 9–1615.7%
49ers by 17+8.9%

Where the luck was

Take the luck out

The final margin was Seahawks by 10. Remove the luck, one kind at a time, and it becomes Seahawks by 8.2.

Each row takes one kind of luck out of the margin. Color shows which team it helped. Luck shares are the fitted ones (how much of each component is luck).

The kicks

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

  • J. Myers, 47 yds missed · 80% expected
  • J. Myers, 45 yds made · 83% expected
  • E. Pineiro, 48 yds made · 79% expected
  • J. Myers, 31 yds made · 96% expected
  • J. Myers, 26 yds missed · 99% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

49ers’ chance of winning

As low as 0% and as high as 59%. 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 49ers were ahead in it, below while the Seahawks were.
#WhenWhat happenedWin probability forNext drive
1 Q1 7:27 The Seahawks were stopped on 4th & 43rd & 4th downs · 37% expected +9% SF SEA: Touchdown
2 Q1 4:37 The Seahawks converted 3rd & 23rd & 4th downs · 60% expected +9% SEA SEA: Touchdown
3 Q2 12:32 J. Myers missed 47-yard field goalKicks · 80% expected for him, 63 of 83 from 45+ before +7% SF SEA: Field goal
4 Q2 4:00 The 49ers converted 3rd & 113rd & 4th downs · 26% expected +7% SF SF: Field goal
5 Q3 5:22 The 49ers were stopped on 3rd & 23rd & 4th downs · 60% expected +6% SEA SF: Punt
6 Q3 4:31 The Seahawks fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +7% SEA SEA: Field goal
7 Q3 3:48 The Seahawks converted 3rd & 173rd & 4th downs · 19% expected +9% SEA SEA: Field goal
8 Q4 10:27 The 49ers were intercepted on a well-placed throwInterceptions · 0% expected to stay out of the defense's hands +12% SEA SF: 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.

  • Trent Williams (SF T), out · 1.1 pts
  • Ricky Pearsall (SF WR), out · 0.6 pts
  • Curtis Robinson (SF LB), out · 0.3 pts
  • Charles Cross (SEA T), out · 1.0 pts
  • Coby Bryant (SEA S), out · 0.4 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

Seahawks 95% · 49ers 5%

Final margin
Seahawks by 10
Luck in points
1.8 for the Seahawks
Luck-adjusted margin
Seahawks by 8.2
Replay with same day's form
Seahawks 45% · 49ers 55% unchanged: why
How much of each is luck?

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

What counts

We tested momentum on 19,000 lucky breaks and found none, so it's off by default. 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 18 2025 games · Seahawks · 49ers

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