Most bowling leagues and amateur tournaments use a handicap system, which allows bowlers with unequal skill levels the opportunity to compete against each other. A handicap is basically a percentage of the difference between your bowling average and a base average. If you know how to figure out your own or your team's handicap, or you’re involved in setting up a league or tournament, you can give all bowlers an equal chance at winning.
Calculate your average score based on the past three or four official games bowled. Total the scores and divide by the number of games bowled. For example, if the scores from three past games are 136, 148 and 150, the total divided by three is 146.7. Drop the fraction of a pin for an average score of 146.
Find out what base or basis average to use in the calculation. This is usually a score higher than any other bowler's average. If you are calculating your own handicap, this information can be obtained from the league coordinator or tournament official. The basis average may be different from one league or tournament to the next, but it's not uncommon to use 200, 210 or 220.
Find out what percentage factor to use. If you are calculating your own handicap, this information can be obtained from the league coordinator or tournament official. The percentage factor may differ between leagues and tournaments, but a factor of 80, 90 or 100 percent is commonly used. If you are organizing an event, keep in mind that the lower the percentage factor used, the more the advantage goes to the high-average bowler.
Take the average score from Step 1 and subtract it from the basis average obtained or selected in Step 2. Multiply the difference by the percentage factor obtained or selected in Step 3. For example, if you use a basis average of 200, subtract 146 from 200, giving 54. If you use a percentage factor of 90 percent, multiply 54 by 0.90, resulting in 48.6. Drop the fraction of a pin for a handicap of 48 pins.
Calculate team handicaps in a similar manner. Determine each team member's average and add the averages, resulting in the team's average. Subtract this from a selected team basis average, which is set higher than any team's average. Multiply the difference by the percentage factor to determine the team's handicap. For example, if a team's average is 750 and you're using a team basis average of 800, the difference is 50. If you're using a percentage factor of 90 percent, multiple 50 by .90, resulting in a team handicap of 45 pins.