Bowling Series Calculator: Series Total, Average and Handicap Score
Add up a 2 to 6 game bowling series, get the series average, high and low game, and your handicap per game and handicap series from your league basis score and percentage, using the USBC rule of dropping fractions or normal rounding.
How it works
Scratch series = sum of the games · Series average = series ÷ number of games · Handicap per game = (basis − average) × percentage, fractions dropped (USBC) or rounded, minimum 0 · Handicap series = scratch series + handicap × number of games
League bowling is usually scored over a three-game series (some leagues and tournaments bowl two, four or six games). Your scratch series is the plain sum of the games, and the series average is that sum divided by the number of games. Handicap evens out a league by giving lower-average bowlers extra pins in every game. The standard method takes the difference between a fixed basis score (often 200 to 230) and your average, then applies a percentage. USBC rules use 100% unless the league chooses otherwise; 80% and 90% are common. USBC also says fractions are dropped when you figure averages and handicap, so 49.5 becomes 49. Some leagues round instead, so you can switch this under More options. On league night your handicap normally comes from your established average (or entering average early in the season), not from the games you just bowled. Enter that under More options to see your official handicap series and how many pins you bowled over or under your average. If your average is at or above the basis score your handicap is 0, and an optional cap limits handicap for leagues that set a maximum.
Worked example
Games of 165, 178 and 152 make a scratch series of 495 and a series average of 165.00. With a basis of 220 at 90%: (220 − 165) × 0.90 = 49.5, and dropping the fraction under USBC rules gives a handicap of 49 pins per game. The handicap series is 495 + 49 × 3 = 642. With rounding instead, the handicap would be 50 and the series 645.
Sources: USBC Playing Rules 2026–2027 (Rule 100d: handicap percentage, dropping fractions) · USBC Rules and league resources
Frequently asked questions
How do I calculate my bowling handicap?
Subtract your average from the league basis score and multiply by the league percentage. With a 220 basis at 90% and a 165 average: (220 − 165) × 0.9 = 49.5, which is 49 pins per game once the fraction is dropped.
Does USBC round handicap up or down?
Neither: USBC rules say fractions are dropped when figuring averages and handicap. A 49.9 handicap is 49, and a 165.8 average is 165. Your league can adopt a different rule, so check its rules sheet.
Is handicap based on tonight’s series or my league average?
Usually your league average from previous weeks, or your entering average at the start of the season. Using tonight’s average would reward bowling badly, so leagues lock it in before you bowl.
Why is my handicap zero?
Your average equals or beats the basis score, so the difference is zero or negative and handicap floors at 0. That is why USBC suggests a basis above the league’s highest average.
What handicap percentage do leagues use?
USBC’s default is 100% of the difference, but many recreational leagues use 80% or 90%. A higher percentage gives lower-average bowlers a bigger cushion.
What is a good three-game series?
For most league bowlers, a 600 series (a 200 average) is a milestone; 700 is excellent and 800 is rare. The maximum is 900, three perfect 300 games.
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This calculator is for educational purposes. Double-check important results before acting on them.