Rules

1.1The lane

A lane is 60 feet from the foul line to the center of the head pin and about 41.5 inches wide, with gutters on both sides. Bowlers deliver the ball from the approach, the area behind the foul line.

• Arrows and dots on the lane are aiming marks only.

1.2Pins

Ten pins stand in a triangle numbered 1 to 10 from front to back and left to right, with 12 inches between pin centers. The 1 pin (head pin) is closest to the bowler.

• Back row, left to right: 7, 8, 9, 10.

1.3The ball

Bowlers may use their own ball or a house ball. A ball may weigh no more than 16 pounds, and personal balls must be a model approved by USBC.

1.4No changing the ball surface during competition

Once competition starts, a ball may not be sanded or scuffed, cleaned with a liquid, or treated with powder, rosin or other material. You may wipe it with a dry towel.

• Competition starts when any bowler throws a ball for score.
• Sanding, polishing and cleaning before that point are allowed.
• If residue won't come off with a towel, a league officer may allow an approved cleaner.

1.5Shoes and the approach

Wear bowling shoes, and don't put anything on the approach or your soles that leaves residue. Slide products are allowed only if they leave nothing behind.

• If another bowler's product makes the approach slippery, ask a league officer to step in.

2.1Individual competition

In individual (singles) play each bowler bowls their own games. Matches are decided head to head or by standings across the season, as the league sets.

2.2Team size

Each team has a fixed number of bowlers in its lineup, set by the league (commonly four). The league also sets the maximum roster size, including substitutes.

2.3Lineup order

Bowlers bowl in lineup order every frame. The order cannot change once a game has started, and a substitute takes the place in the order of the bowler they replace.

• In leagues that award points bowler against bowler, the order is fixed for the whole night.

2.4Legal lineup

A team must have its league-required minimum number of bowlers present before the first frame is completed, or it forfeits. Unless the league says otherwise, substitutes count toward the minimum.

• Leagues may set a later frame but cannot require the full lineup before the game starts.
• Leagues may let one eligible bowler count as a legal lineup.

2.5Substitutes

A captain may replace a bowler with another eligible bowler at any point in a game. A bowler who is taken out cannot return in that game. A substitute's scores count for the team, and the substitute keeps an average of their own.

• In a handicap league, when a bowler is replaced partway through a game each of the two gets one-tenth of their handicap for each frame they bowled.

2.6Late-arriving bowler

A bowler who arrives after a game has started may join in the frame the team is bowling at that moment. Unless the league says otherwise, each frame missed is scored as one-tenth of their absent score.

Example: A bowler with a 170 absent score arrives as the team bowls frame 3. Frames 1 and 2 are scored 17 pins each, then the bowler bowls frames 3–10.

3.1Practice

The league decides how much practice bowlers get on their pair before the first game, usually a set number of minutes.

3.2Alternating lanes

A league game is bowled on a pair of adjoining lanes. Opposing teams bowl one frame on one lane and the next frame on the other, so each team bowls five frames on each lane of the pair.

• Each game starts on the lane where the team finished the game before.
• A league may instead have each game bowled on a different pair.

3.3Lane courtesy

By long custom, not by a written rule: wait for the bowlers on the lanes beside you to finish before stepping up, and when two bowlers are ready at once the one on the right goes first.

• Stay in your own lane's approach area.
• Don't distract a bowler who is on the approach.

3.4Delay of game

Bowlers must be ready when it's their turn. A bowler or team that refuses to continue after an official directs them to forfeits the game or series.

4.1Delivery

A delivery is made when the ball leaves the bowler's hand and crosses the foul line onto the lane. A ball dropped on the approach that doesn't cross the foul line is not a delivery.

4.2Foul

It's a foul if any part of your body goes past the foul line and touches the lane, equipment or building during or after a delivery. The delivery counts, but any pins knocked down score zero.

• The ball stays in play until the next bowler is on the approach.
• Crossing the line while still holding the ball is not a foul.
• The ball touching the foul detector is not a foul.

Example: You foul on your first ball and knock down 8 pins. You score 0 for that ball, the pins are reset, and you bowl your second ball at a full rack. Knock all ten down and it's marked as a spare.

4.3Deliberate foul

A bowler who fouls on purpose scores zero for that delivery and gets no more deliveries in that frame.

4.4Calling fouls

Automatic foul detectors are used where available. Otherwise, captains or a foul judge call fouls. A foul that the detector misses but is plainly seen must still be recorded.

5.1Pins that count

Pins count when they're knocked down or off the lane by the ball or by another pin, including pins that bounce off the side partitions, the rear cushion or a sweep bar resting on the deck.

• Pins may not be conceded; they must actually fall.
• A leaning pin resting on the kickback or partition counts as down (dead wood) and is cleared before the next ball.

5.2Pins that don't count

The delivery counts but the pins don't when the ball leaves the lane before reaching the pins, the ball bounces back off the rear cushion, the pinsetter knocks pins down, pins fall while dead wood is being cleared, or the bowler fouls.

• The same applies if the ball hits dead wood lying on the lane or in the gutter before leaving the lane.
• If the bowler has another ball in the frame, the illegally downed pins are reset where they stood.

Example: The ball hops out of the gutter and knocks down the 10 pin. The pin doesn't count.

5.3Pins that bounce back up

A pin that rebounds and ends up standing on the lane counts as standing.

5.4Misplaced or broken pins

Check the rack before you bowl and ask for misplaced pins to be reset. If you bowl at a bad rack, the result stands. A broken pin is replaced right away and doesn't change the score.

• Between deliveries, standing pins aren't moved unless the pinsetter moved them or they're out of the sweep's range; they're then reset where they stood.

6.1Dead ball

When a dead ball is called, that delivery doesn't count, the pins are reset as they were, and the bowler bowls again.

• Pins were missing from the rack and this is noticed right after the delivery.
• A pin moves or falls before the ball reaches the pins.
• The ball hits a foreign object on the lane, such as a lowered sweep bar.
• The bowler bowls on the wrong lane or out of turn (see 6.2).
• The bowler is touched by another person or a moving object during the delivery; the bowler may instead accept the result.

6.2Bowling on the wrong lane

If one bowler bowls on the wrong lane, or one bowler from each team does, it's a dead ball and they rebowl on the correct lane. If more than one bowler from the same team bowls on the wrong lane in turn, the frame stands and the next frames go back to the correct lanes.

6.3Disputed calls and provisional balls

If a call on a first ball is disputed and can't be settled right away, the bowler finishes the frame and then bowls one provisional ball at a full rack. The league or tournament officer decides which score counts.

• No provisional ball is needed for a disputed second ball or the third ball of the 10th frame.

7.1Frames

A game has ten frames. In frames 1–9 each bowler has two balls to knock down all ten pins, unless the first ball is a strike. A frame's score is the pins knocked down plus any strike or spare bonus.

• The score shown in each frame is the running total for the game.

7.2Strike

Knocking down all ten pins with the first ball is a strike, marked X. It scores 10 plus the pins from your next two balls.

• Two strikes in a row is a double; three is a turkey.

Example: Strike, then 7 and 2 in the next frame: the strike frame scores 10 + 7 + 2 = 19.

7.3Spare

Knocking down all remaining pins with your second ball is a spare, marked /. It scores 10 plus the pins from your next ball.

Example: 7 then 3 is a spare. A 6 on the next ball makes the spare frame worth 10 + 6 = 16.

7.4Open frames and splits

A frame without a strike or spare is an open frame and scores just the pins knocked down. A split is a leave after the first ball where the head pin is down and the standing pins have a gap between them; it's circled on the sheet.

• A miss on the second ball is marked with a dash (–).

7.5The 10th frame

In the 10th frame, a strike earns two more balls and a spare earns one more, so you may bowl up to three balls. With an open 10th you bowl two balls.

• The extra balls only complete the strike or spare bonus; they don't start a new frame.

Example: X, X, X in the 10th scores 30 for that frame.

7.6Perfect game

The highest possible score is 300: twelve strikes in a row, every frame scoring 30.

8.1Average

A bowler's average is total pins divided by games bowled in that league, with fractions dropped. Averages are updated after every session.

Example: 1,623 pins in 9 games = 180.3, so the average is 180.

8.2Entering average

On the first night, a bowler uses last season's average from a comparable league. A bowler with no qualifying average sets one from their first session, unless the league says otherwise.

In this league: Total pins divided by games bowled this season, with fractions dropped, worked out again after each night. A bowler has an average of their own after 3 games. Until then they use the entering average the league gave them, or bowl without a handicap if they have none; those first nights are then given the handicap their first 3 games establish.

8.3Handicap

Handicap is pins added to each game for a bowler or team, based on average, so players of different skill compete on a more even footing. It's figured as a percentage of the difference between a basis score and the bowler's average, with fractions dropped.

• USBC's default is 100% when a league hasn't set a percentage; many leagues use 80% or 90%.
• Team handicap is the sum of its bowlers' handicaps. USBC recommends this individual method over handicapping the difference between team averages.

Example: At 90% of 220, a bowler averaging 160 gets (220 − 160) × 0.9 = 54 pins per game.

In this league: 90% of the difference between 220 and the bowler's average, with fractions dropped. A bowler averaging 220 or more gets none. It is set before each night and is the same for every game that night.

8.4Handicap basis score

The league chooses the basis score. It should be higher than the highest entering average so no bowler gets negative handicap, unless the league chooses to allow it.

• Example: if the top entering average is 218, a basis of 220 works.

8.5Scratch and handicap scores

A scratch score is the actual pinfall. A handicap score is scratch plus handicap. Leagues say which one decides matches, and awards can be given for either.

9.1Team points

Teams earn points each night under the league's own point system. A common system gives a set number of points for each game won and more for the higher total pins over the night.

• Some leagues also award points bowler against bowler (see 9.2).

In this league: 2 points for each game a team wins, and 1 point for the night's total pins. Team totals include handicap. A tie splits the points for that game or series.

9.2Individual match points

When the league awards individual points, each bowler is matched against an opponent in the same lineup position, and the higher score each game (scratch or handicap, as the league sets) earns the point.

9.3Tied games

When a game or the night's total is tied, each team is credited half the points it is worth. Ties like these are not rolled off.

9.4Absent bowler score

When a regular bowler is missing and no substitute bowls, the team counts an absent score for them. Unless the league sets something else, that is the bowler's average less 10 pins for each game, with a handicap based on their average.

• An absent score can be used only when the team has a legal lineup present.
• An absent bowler with no average yet is scored 120.
• In leagues with bowler-against-bowler points, a bowler facing an absent score must bowl at least their own average less 10 to win the point.

Example: An absent bowler averaging 180 is scored 170 per game.

In this league: An absent bowler is scored their average less 10 pins for each game, plus their handicap. An absent score counts for the team and never toward the bowler's own average.

9.5Vacancy score

An empty spot on a team that has fewer bowlers than the league's lineup is a vacancy. In adult leagues it scores 120 pins a game unless the league sets another value.

• In a handicap league the vacancy's handicap is worked out from that score.

In this league: An empty seat on a team is scored 125 for each game, plus the handicap that score earns.

9.6Bowling with no opponent

When a team has no opponent for the night, because the league has an odd number of teams or a team has withdrawn, the league's own rule decides how it earns its points. A common rule has the team bowl against its own average less a set number of pins.

In this league: A team with no opponent wins a game's points by bowling at least its team average coming into the night less 40 pins, handicap counted on both sides, and wins the total pins by reaching the same mark over the night. Bowling well over average is never a loss.

9.7Ties in the standings

Each league decides how teams level in the standings are separated. Under USBC rules a tie for first place at the end of the schedule is settled by a roll-off unless the league allows co-champions, and total pins for the season cannot be used to break it.

In this league: Teams level on points are separated by total pins (with handicap), then head-to-head, then a coin flip recorded by the league. Head-to-head counts only when the tied teams have all played each other equally.

9.8Eligibility for awards

To qualify for individual league prizes a bowler must bowl at least two-thirds of the scheduled games, unless the league sets a different share.

In this league: A bowler is ranked on the Leaders page after bowling at least 67% of the games bowled so far. Absent and vacant scores never count toward a bowler.

10.1Sportsmanship

Bowlers are expected to behave courteously. Abusive language, damaging equipment and unsporting conduct can lead to a warning, removal from the session or league discipline.

10.2Disputes and protests

Captains try to settle a dispute on the lanes first. One that cannot be settled goes to the league's officers as a written protest, which must be filed within 15 days of the night in question, or within 72 hours when it concerns the last two weeks of the schedule or a roll-off.