Baseball Game Length and Extra Innings Interpreter

How long a baseball game is, and what happens when the scores are level, are a competition’s rules rather than the sport’s. The automatic runner on second, the seven-inning doubleheader and the pitch timer all arrived on dates Major League Baseball’s own announcements give, and two of the three have already changed again.

Regulation length, by competition and period

The extra-innings rule is three different rules

The recent changes, with the announcement that carries each

Nine innings is a competition’s rule, and four of the rules around it changed in four years

Everything on this page is some body’s rule for some period, and none of it is a property of baseball. Major League Baseball, the minor leagues, Nippon Professional Baseball, the KBO League, the NCAA, US high school baseball under the NFHS and Little League all publish their own, they do not agree with each other, and several of the numbers below changed within the last five years on dates their own announcements give. So every figure here is printed with the body that published it and the season or edition it belongs to, and where this page could not read a competition’s own document it says so rather than assuming the rule carries across.

Start with the length, because every per-game rate in the sport depends on it. A Major League game is nine innings. A US high school game is seven, under NFHS Rule 4-2-1 — “A regulation interscholastic game consists of seven innings (turns at bat)” — and that text was read through a reproduction carrying no edition year, so it is cited as the NFHS’s standing rule and not dated to a season. Major League Baseball has itself played seven-inning games recently: doubleheaders in the shortened 2020 season, kept for 2021, which did not return for 2022. The consequence runs through this whole section of the site. The nine in an earned run average, in strikeouts per nine innings and in a range factor per nine innings is this regulation length rather than a constant, which is why the earned run average calculator takes it as a field and the WHIP and pitching rates calculator and the fielding percentage and range factor calculator both say which base they are on.

The automatic runner is the clearest case of a rule with a date, and it is also where this site found a secondary source to be wrong. Major League Baseball’s own announcement of 13 February 2023 says the competition committee “voted on Monday to make two additions to the 2023 rulebook”, one of them making permanent the runner placed on second base to start each extra half-inning. The same announcement records that it “was instituted in 2020 in an effort to preserve player health and safety during the pandemic-shortened season”, and — the clause that matters most — that it “applies only to regular-season games”. A secondary source read for the earlier baseball batch reported the runner being withdrawn for 2022; it was wrong about that and right, in the same piece, about the seven-inning doubleheaders ending. Both sources are in the references with what each one supplied, and MLB’s own announcement is the one followed. One thing neither batch could establish from a rulebook text is whether a run that the automatic runner scores is earned, so nothing is claimed about it on any page here.

Which means the same competition runs two different extra-innings rules in the same year. A level regular-season game gets the runner; a level postseason game does not, on the strength of that one clause. That is worth stating as plainly as possible because it is the thing a page writing “the extra-innings rule in baseball” gets wrong without noticing. It also means a team’s extra-innings record, a reliever’s extra-innings workload and the number of runs scored in a tenth inning all mean different things before 2020, between 2020 and 2022, and in October. Other sports resolve a tie by leaving the format of play altogether, which is a different design: cricket’s answer is on the super over and tie resolution interpreter.

Four more dated changes, all Major League Baseball’s. The pitch timer was announced on 9 September 2022 for the 2023 season: “Pitchers will have up to 15 seconds between pitches when the bases are empty” and “up to 20 seconds between pitches with at least one runner on base”, with two rubber disengagements a plate appearance and the batter required to be in the box and alert with at least eight seconds left. It was then revised on 21 December 2023 — “Reduce time from 20 seconds to 18 seconds with runners on base” — and the same announcement cut mound visits from five a game to four. The shift restrictions arrived with the timer: “Two infielders must be positioned on each side of second base when the pitch is released”, and “All four infielders must have both feet within the outer boundary of the infield when the pitcher is on the rubber”, with no switching sides unless a substitution is made. And the bases grew from 15-inch squares to 18-inch squares. Every one of those is dated, is MLB’s, and applies to no other competition except where that competition adopted it separately.

On whether any of it shortened the games, this page quotes one figure and declines another. MLB’s December 2023 announcement reports that the average nine-inning game time “increased seven minutes from April to September (five minutes after controlling for the number pitches, breaks, and runs scored)” during 2023 — an increase, which is the opposite direction from the usual summary and is MLB’s own measurement of its own rule. A 26-minute reduction in average game time also appears in the September 2022 release, and what it compares could not be established from the text, so it is not used on this page. The September 2022 release’s Minor League figures that ARE clearly attributed — 0.45 pitch-timer violations a game and a 13.5% fall in base-related injuries — are about violations and injuries rather than about length.

What this page will not do. It carries no regulation length for the minor leagues, Nippon Professional Baseball, the KBO League or the NCAA, because none of those documents was read for it, and several of them differ. It states no NFHS extra-innings procedure, because NFHS rules are adopted and modified by state associations and no procedure was read. And it makes no claim about whether an automatic runner’s run is earned. Those are absences printed rather than filled. For the published limits on how long a young pitcher may be left in a game, which are a different body’s rules again, see the pitch count and rest interpreter; for the starter’s verdict whose six-inning threshold assumes exactly the nine-inning game described here, see the quality start interpreter; and for how a season’s length feeds a standings calculation, see the magic number and games behind calculator.

Frequently asked questions

Related calculators

References

1. Major League Baseball. “Automatic runner permanent; new position-player pitching rules”, mlb.com, 13 February 2023 — the committee “voted on Monday to make two additions to the 2023 rulebook”; the automatic runner “was instituted in 2020 in an effort to preserve player health and safety during the pandemic-shortened season” and “applies only to regular-season games”. Read 12 Oct 2026.
2. Potanko C. “No ghost runner, 7-inning doubleheaders and universal DH, oh my!” Pittsburgh Baseball Now, 11 March 2022 — “seven-inning doubleheaders will not return for the 2022 season”, the rule having been introduced for the shortened 2020 season and kept for 2021. Its further report that the extra-innings runner was ending is contradicted by MLB’s own February 2023 announcement, which is followed instead (read 12 Oct 2026).
3. Major League Baseball. Press release: MLB announces rule changes for 2023 season, mlb.com, 9 September 2022 — the pitch timer: “Pitchers will have up to 15 seconds between pitches when the bases are empty” and “up to 20 seconds between pitches with at least one runner on base”, with two rubber disengagements per plate appearance and the batter required to be in the box and alert with at least eight seconds left. The shift restrictions: “Two infielders must be positioned on each side of second base when the pitch is released”, “All four infielders must have both feet within the outer boundary of the infield when the pitcher is on the rubber”, and no switching sides without a substitution. The bases “increase from the standard 15” square to 18” square”. Minor League testing figures given: 0.45 pitch-timer violations a game and a 13.5% fall in base-related injuries. A 26-minute game-time figure also appears without a comparison this reader could establish, and is NOT used on any page here (read 15 Oct 2026).
4. Major League Baseball. Press release: MLB announces competition committee modifications for 2024 season, mlb.com, 21 December 2023 — “Reduce time from 20 seconds to 18 seconds with runners on base”; “Mound visits will be reduced from five per game to four”; a new pitcher stepping onto the warning track with under two minutes left on the inning break clock resets it to 2:00 rather than 2:15; and “A pitcher who is sent out to warm up for an inning must face at least one batter”. On game length it reports the opposite direction from the usual summary: in 2023 the average nine-inning game time “increased seven minutes from April to September (five minutes after controlling for the number pitches, breaks, and runs scored)” (read 15 Oct 2026).
5. National Federation of State High School Associations. NFHS Baseball Rules, Rule 4-2-1 — “A regulation interscholastic game consists of seven innings (turns at bat)”. Read on baseballrulesacademy.com, 12 Oct 2026; that reproduction carries no edition year, so the seven innings are cited as the NFHS’s standing rule rather than dated to a season.
6. Office of the Commissioner of Baseball. Official Baseball Rules, 2024 Edition (ISBN 978-1-63727-386-9), fetched as a PDF 12 Oct 2026. Its extracted text is 109,942 characters and stops inside Rule 5.09, while its own contents page lists Rule 9.16 on page 132 and Rule 9.21 on page 141 — so the scoring chapter is cited below through a reproduction and MLB’s own glossary, not from this document.
7. Major League Baseball. Glossary: Earned Run Average (ERA) — ERA “represents the number of earned runs a pitcher allows per nine innings”, “with earned runs being any runs that scored without the aid of an error or a passed ball”, and “The formula for finding ERA is: 9 x earned runs / innings pitched.” It does not explain the 9. mlb.com (read 12 Oct 2026).
8. Major League Baseball. Glossary: Innings Pitched (IP) — “Because there are three outs in an inning, each out recorded represents one-third of an inning pitched.” The entry does NOT state the “.1 and .2” scorebook notation, so this page demonstrates the notation from published lines instead. mlb.com (read 12 Oct 2026).