Baseball Rules for Beginners: Innings, Outs, Force Plays and the Rules That Confuse Newcomers

Baseball is played between two teams of nine, and every rule serves one contest. The batting team tries to turn batters into runners and runners into runs; the fielding team tries to stop it by recording outs. Each team bats until it makes three outs, a regulation game lasts nine innings, and whoever has scored more runs at the end wins.

Almost everything else in the rulebook is detail about how outs are made and when runners may advance. This guide follows the 2026 edition of the Official Baseball Rules, which govern Major League Baseball and its affiliated minor leagues. The book's foreword notes that many amateur organisations play under the same rules and may modify field and equipment specifications to suit, so a youth league's rules can differ in detail.

The four things to track on every pitch

Innings, and when a game ends

Rule 7.01(a) sets a regulation game at nine innings, extended for a tie or shortened when the home team does not need its half of the ninth. MLB's regulation game entry spells out the weather cases: a game becomes official once the visitors have made 15 outs with the home team leading, or once the home team has made 15 outs regardless of the score.

A tie after nine continues into extra innings. Under Rule 7.01(b)(2), every half-inning after the ninth now begins with a runner on second base: the player just ahead of that half-inning's leadoff hitter in the batting order, or a pinch-runner for him. For earned-run purposes he is treated as if he reached on an error, though no error is charged. Rule 7.02(g) says the placed runner does not apply in the Wild Card Series, Division Series, League Championship Series or World Series, so postseason extra innings start with the bases empty.

Outs, and the runs they cancel

A batter is out when his fly ball is caught, fair or foul, or when a third strike is caught by the catcher, along with a list of rarer cases in Rule 5.09. A runner is out when he is forced out or tagged out, which the next section covers.

One rule that surprises newcomers is Rule 5.08(a). A run does not count if the third out of the same play is made:

• on the batter-runner before he touches first base;
• on any runner who is forced out; or
• on a runner ahead of him who missed a base and is called out on appeal.

So with two outs and a runner on third, a ground ball on which the runner crosses home plate before the batter is thrown out at first produces no run. The out at first ended the inning on the batter-runner, and the run never happened.

The count

The rulebook's definition of a strike includes a pitch the batter swings at and misses, a pitch in the strike zone he does not swing at, a foul ball with fewer than two strikes, a bunt that goes foul, and a foul tip. A ball is a pitch outside the zone that the batter does not swing at; one that bounces through the zone is still a ball. The zone itself runs from the midpoint between the top of the shoulders and the top of the uniform pants down to the hollow beneath the kneecap.

Two consequences matter for beginners. A foul ball with two strikes normally changes nothing, but a two-strike bunt that goes foul is a strikeout. And a walk does not always take four pitches: the base on balls definition lets a manager signal an intentional walk, and the umpire awards first base without a pitch.

The 2026 season added a new layer. MLB's ABS Challenge System keeps the plate umpire calling every pitch, but each club starts a game with two challenges and keeps any that succeed. Only the pitcher, catcher or batter may challenge, immediately and without help from the dugout. A challenged pitch is judged against a rectangle the width of home plate, with its top and bottom set at 53.5% and 27% of the batter's certified height, rather than against the rulebook's shoulders-to-kneecap description.

Force out or tag out?

The Official Baseball Rules define a force play as one in which "a runner legally loses his right to occupy a base by reason of the batter becoming a runner." Because only one runner may stand on a base, a runner on first must run when the batter hits a ground ball. So must a runner on second if first base is also occupied, and a runner on third if the bases are loaded.

• A force out: runner on first, ground ball to the shortstop. The runner has to go to second, so the shortstop or second baseman only needs to step on second base while holding the ball.
• A tag out: runner on second, first base empty, ground ball to the shortstop. Nobody is behind the runner, so he is not forced. If he breaks for third, a fielder has to touch him with the ball, or with the glove holding it securely.

The force can disappear in the middle of a play, which the rulebook's own comment illustrates. With runners on first and third and one out, suppose the ball is hit to the first baseman, who steps on first. The batter is out, and the runner going to second is no longer forced, so he must now be tagged — and if a runner from third crosses the plate before that tag, the run counts. Had the first baseman thrown to second first for a force out and then taken the return throw at first, the third out would have come on the batter-runner before he reached first, and no run could score. MLB's force play entry puts the same principle in one line: once the defence forces out a trailing runner, it must tag the runners ahead of him.

Tagging up on a fly ball

When a fly ball is in the air, runners face a choice: go, or go back. The rulebook's definition of a catch settles the timing: "Runners may leave their bases the instant the first fielder touches the ball." The touch counts even if the catch is juggled and completed later.

A runner who leaves too early is not called out automatically. Under Rule 5.09(c)(1) he is out on appeal if the defence tags him, or his original base, before he gets back; the rule's comment says a retouch means "to tag up and start from a contact with the base after the ball is caught," with no running start from behind the bag. The appeal has to come before the next pitch or play. Runners do not have to tag up on a foul tip, and may even steal on one.

The 2026 edition amended Rule 5.06(b)(1) to clarify a runner's retouch duties further. The current text treats a runner as having passed a base once both feet are on the ground beyond it, requires him to retouch a passed base before advancing again, and adds diagrams in a new Appendix 6.