---
name: football-rules
description: Answers American football rules questions correctly for the NFL and NCAA FBS, keeping the two codes and their season-by-season changes apart — catch rule, down by contact, overtime, clock and two-minute rules, kickoff and touchback spots, onside kicks, pass interference, intentional grounding, targeting, fumble rules, safeties and touchbacks, untimed downs, replay challenges, tush push, NFL vs college differences, and passer rating vs NCAA passing efficiency. Use when explaining a call, settling a rules dispute, scoring a play, or reading sack and passing stats.
---

# Football rules: NFL and NCAA

Sources: 2026 Official Playing Rules of the NFL (cited "NFL r-s-a") and 2026 NCAA Football Rules and Interpretations, May 2026 (cited "NCAA r-s-a"). Both books change every year. Anything below marked with a season is the rule as of that season; for a play from an earlier year, apply that year's rule.

## Work every rules question in this order

1. **Level and season.** NFL or NCAA, and which year. If the user doesn't say, ask, or answer both. Never carry an NFL rule into a college game or the reverse. Kickoffs, overtime, the clock and targeting all changed between 2023 and 2026.
2. **Game situation.** Quarter and time, down and distance, ball spot, score. Before or after the two-minute warning (NFL) or Two-Minute Timeout (NCAA)? Fourth down? A try? Overtime?
3. **What happened, in order.** Who had possession; whether it was a catch, muff, fumble, backward pass or forward pass; where the ball became dead and why. For a goal-line play, decide which team provided the impetus.
4. **Fouls.** Live-ball or dead-ball; before or after a change of possession; one team or both (offsetting).
5. **Enforcement spot and distance.** Previous spot, spot of foul, or succeeding spot; then half-the-distance; then the automatic first down or loss of down.
6. **Result.** Next down, distance, spot, clock status (starts on the ready signal or on the snap), and whether the period is extended.
7. **Say how sure you are.** Cite the rule. For a play that turns on official judgment, a case-book ruling, or a rule outside this skill, say so and point to the current rulebook or case book.

## Differences models get wrong most often

| Topic | NFL | NCAA |
|---|---|---|
| Catch | Control, then **both feet** or another body part down inbounds, then a football act (or time to do one) (3-2-7) | Control, then **any part of the body** inbounds (one foot), then hold it long enough for an act common to the game (2-4-3) |
| Runner down | Only when **contacted by an opponent** and a knee, elbow or other body part (not hand or foot) touches the ground (7-2-1-a); he can also give himself up | **Untouched counts.** Dead when any part other than hand or foot touches the ground (4-1-3-b); holder or kicker on a place kick is the exception. A feet-first slide ends the play at the start of the slide (4-1-3-r) |
| Try spot | Kick snapped from the 15; two-point from the 2 (11-3-1) | All tries snapped from the 3 (8-3-2-c) |
| Defensive score on a try | 2 points (11-3-2-b) | 2 points; a safety on a try is worth 1 (8-1-1) |
| Kickoff touchback | 35 if it lands in or is downed in the end zone; 20 if it lands in the landing zone and then goes to the end zone (6-1-5, 2025+) | 25 (8-6-2). A fair catch of a free kick inside the 25 is placed at the 25 (6-5-1-a) |
| Onside kick | Must be declared to the Referee. Any team, any time, from 2026; 2025 required the kicking team to trail; 2024 required trailing and the fourth quarter (6-1-6) | No declaration. At least four kickers on each side of the kicker (6-1-2-c-3) |
| Defensive PI | Spot foul, first down; in the end zone, first down at the 1, or half the distance to the goal if the previous spot was inside the 2 (8-5) | Spot foul if under 15 yards beyond the previous spot; otherwise 15 yards from the previous spot; first down (7-3-8-c) |
| Offensive PI | 10 yards from the previous spot (8-5) | 10 yards from 2026; was 15 through 2025 (7-3-8-b) |
| Intentional grounding | Loss of down and 10 yards, or at the spot if that is farther; safety if thrown from the end zone (8-2-1) | Loss of down at the spot (7-3-2-h) |
| Throw-away exemption | Passer outside the **pocket area**; ball lands at or beyond the line of scrimmage extended (8-2-1 Item 1) | Passer outside the **tackle box**; ball crosses or lands beyond the neutral zone extended (7-3-2 Exc.) |
| Head contact | Use-of-helmet and defenseless-player fouls, 15 yards (12-2-9, 12-2-10); ejection only if flagrant; league discipline afterward | **Targeting** (9-1-3, 9-1-4): 15 yards plus disqualification, confirmed by replay. 2026 trial: first offense = rest of that game only |
| Horse-collar | 15 yards plus automatic first down; not a foul against a runner in the pocket area or in close-line play (12-2-16) | 15 yards; applies inside the tackle box too (9-1-15) |
| Fourth-down / late fumbles | On 4th down, and on **any down after the two-minute warning**, only the fumbler may recover and advance for his team (8-7-5, 8-7-6) | **Fourth-down rule only** (7-2-2-a Exc. 2). No two-minute fumble rule |
| First downs and the clock | Clock doesn't stop for a first down | Clock stops for a first down only after the Two-Minute Timeout of each half (3-3-2-e-1, since 2023) |
| Overtime | Timed periods from the 35; both teams get the ball once; regular season 10 min, can end tied (16-1-3) | Possessions from the opponent's 25; mandatory 2-point try from the second overtime; 2-point plays only from the third (3-1-3) |
| Challenges | 2, plus a third if one succeeds; none after the two-minute warning or in overtime (15-1) | 2, plus a third if either succeeds, from 2026; must have a timeout; replay official reviews every play (12-5-1) |
| Pushing the runner (tush push) | Legal. Pulling a runner is a foul (12-1-4); the 2025 ban proposal failed, and none was on the 2026 agenda | Pushing legal, pulling a foul, 5 yards (9-3-2; A.R. 9-3-2-I) |

Full table with more rows, and the change log by season: `references/nfl-vs-ncaa.md`.

## Rules that hold in both codes

- **Safety vs touchback depends on impetus**, not on who last touched the ball. If your own team's impetus puts the ball behind your goal line and it dies there or out of bounds, it's a safety. If the opponent's impetus put it there, it's a touchback (NFL 3-16, 11-5, 11-6; NCAA 8-5, 8-6, 8-7).
- **Fumble out of the opponent's end zone**, forward from the field of play, is a touchback for the defense (NFL 8-7-3 Item 4; NCAA 7-2-4-c with 8-6). A forward fumble out of bounds in the field of play comes back to the spot of the fumble (NFL 8-7-3; NCAA 7-2-4-b).
- **Muff vs fumble.** A muff is touching the ball without gaining possession. A receiver who muffs a kick that has crossed the line has not fumbled. The kicking team may recover it but may not advance it. Once a receiver gains possession and then loses it, it is a fumble and anyone may advance it.
- **Half the distance.** No distance penalty may move the ball more than half the distance to the offender's goal line (NFL 14-2-1; NCAA 10-2-6, with defensive PI as the exception).
- **Offsetting fouls** replay the down (NFL 14-5-1; NCAA 10-1-4). NFL exception: 15 yards against 5 yards (5 with no automatic first down, loss of down or runoff) enforces the 15 and ignores the 5. NCAA has no such exception.
- **Free kick after a safety** comes from the kicking team's 20 and may be a punt (NFL 6-1-1, 6-1-2; NCAA 8-5-2).
- **Fair catch kick.** After a fair catch, the receivers may try a field goal from the spot with a place kick (no tee) or drop kick, worth 3. Untimed if the catch ends the half. NFL: 10-2-4, 11-4-3. NCAA: new in 2026 (2-16-11, 6-5-1-e).

## A half or game can't end on

- **NFL:** an accepted defensive live-ball foul, plus specific offensive fouls at the defense's request, a fair catch, or a double foul. The period gets one untimed down (4-8-2).
- **NCAA:** any accepted live-ball foul by either team in the 2nd or 4th quarter (the offended team may decline the extension when the offense's foul carries loss of down), offsetting fouls, an inadvertent whistle, or a fair-catch-kick election (3-2-3).

## Stats conventions

- **Sacks:** NFL subtracts sack yards from **team passing** and leaves the quarterback's individual rushing alone. NCAA charges a sack as a **rushing** attempt and yards lost, for the player and the team. College rushing totals for quarterbacks and teams are lower because of it.
- **Kneel-downs** are scored as rushing attempts for negative yards in both. This is a stat convention, not a playing rule, and hasn't been checked against the current stat manuals.
- **NFL passer rating** (0 to 158.3): four components, each clamped to [0, 2.375]:
  `a = (Cmp/Att − 0.3) × 5`, `b = (Yds/Att − 3) × 0.25`, `c = (TD/Att) × 20`, `d = 2.375 − (Int/Att × 25)`; rating = `(a+b+c+d) / 6 × 100`.
- **NCAA passing efficiency** (uncapped): `(8.4·Yds + 330·TD + 100·Cmp − 200·Int) / Att`.
- Check numbers: 20 of 30, 250 yards, 2 TD, 1 INT gives NFL 100.7 and NCAA 152.0. The two scales aren't comparable; never convert one into the other.

Worked examples and stat-reading traps: `references/stats-and-scoring.md`.

## Reference files

- `references/nfl-vs-ncaa.md`: open for any side-by-side question, kickoff details (dynamic kickoff zones and spots), replay, and the season-by-season change log 2013–2026.
- `references/clock-and-overtime.md`: open for clock starts and stops, two-minute rules, 10-second runoffs, untimed downs, and every overtime format (NFL regular season vs postseason, NCAA by period).
- `references/edge-cases.md`: open for goal-line, impetus, fumble, muff, catch-process, tuck-rule, double-foul, and end-of-half scenarios, worked step by step.
- `references/stats-and-scoring.md`: open for scoring values, passer rating and efficiency math, and how sacks and kneels move rushing and passing totals.

## When to send the user to the book

- Questions that turn on official judgment: catch versus no catch, a football move, targeting indicators, a defenseless player. Explain the criteria; don't predict the call.
- Anything marked "unverified" in the reference files.
- Seasons before 2013. High school (NFHS), FCS-specific or Division II/III quirks. CFL, UFL and other leagues. These skills don't cover them.
- Current-season mid-year interpretations and points of emphasis. Check operations.nfl.com and ncaa.org/playing-rules.