How USBC bowling handicap works
A bowling handicap lets bowlers of very different averages compete on fair terms by adding strokes to the lower scorer. The USBC formula itself is simple arithmetic — but there is one rule that trips up nearly every online calculator: it truncates, it does not round. Here is the whole calculation, with a worked example and a per-game table.
Open the Bowling Handicap calculatorWant the number now? The Bowling Handicap calculator applies everything below — the average, the basis, the percentage and the exact USBC truncation — to the scores and league settings you enter.
What a bowling handicap is for
A handicap is a number of bonus pins added to a bowler's actual (scratch) score so that a newer bowler averaging 130 can compete fairly against a seasoned bowler averaging 210. Rather than only the highest scorer ever winning, the handicap levels competition between bowlers of different averages: the lower your average relative to the league's target, the more pins you receive each game. It is the standard fairness mechanism in USBC-certified league play, and it is calculated the same way every week from your running average.
The USBC handicap formula
There are three pieces: your average, your handicap per game, and your handicapped series total. Each step below applies USBC's truncation rule — note the word TRUNCATED wherever it appears.
- Total pins
- the sum of every game score in your record so far
- Games bowled
- the number of games those pins came from
- Average
- total pins divided by games, with the decimal dropped (truncated to a whole number)
- Basis
- the league's target score, e.g. 200, 210 or 220 — set by the league
- Percentage
- the share of the gap awarded, e.g. 90% or 100% — set by the league
- Handicap per game
- bonus pins added to each game, truncated to a whole pin and never below 0
The key detail: truncation, not rounding
This is where most online bowling handicap calculators are simply wrong. USBC rules truncate — they discard the fractional part — they never round to the nearest whole number. Rounding 145.8 up to 146 or 67.5 up to 68 will give you a handicap that does not match what your league secretary computes, and over a season that difference decides matches.
Work through a single bowler to see the gap:
- Total pins 1,166 over 8 games:
1166 ÷ 8 = 145.75. Truncate the decimal → average 145 (a rounding calculator would use 146). - League uses a 220 basis at 90%:
(220 − 145) × 0.90 = 75 × 0.90 = 67.5. - Truncate 67.5 → handicap 67 per game. A calculator that rounds would give 68, and would have started from average 146 — producing 66 or 67 from a different path. Either way it disagrees with the rule.
The correct answer is the truncated one: 67 pins per game. Drop the decimal at each step — do not round it.
Basis and percentage are set by the league
There is no single national basis score or percentage. Both numbers are chosen by each league, and the league's own rules govern. Common combinations are 90% or 100% of a basis of 200, 210 or 220. A higher basis or a higher percentage awards more handicap pins to below-target bowlers; a 100% basis is designed to fully equalise, while 90% leaves a small edge to the stronger bowler. Because the settings vary, a handicap computed for one league is not portable to another — you must plug in your own league's basis and percentage.
Handicap per game at 90% of a 220 basis
The table below shows the handicap per game for a range of averages, using a 220 basis at 90%. Every value is truncated to a whole pin, and any average at or above the basis is clamped to 0.
| Average | (220 − avg) × 0.90 | Handicap per game |
|---|---|---|
| 120 | 100 × 0.90 = 90.0 | 90 |
| 140 | 80 × 0.90 = 72.0 | 72 |
| 160 | 60 × 0.90 = 54.0 | 54 |
| 180 | 40 × 0.90 = 36.0 | 36 |
| 200 | 20 × 0.90 = 18.0 | 18 |
| 210 | 10 × 0.90 = 9.0 | 9 |
| 220 | 0 × 0.90 = 0.0 | 0 |
Averages between these rows follow the same pattern; where the multiplication produces a
fraction (for example an average of 145 gives 67.5), truncate it down to the whole
pin.
Confirm your league's settings first
Before you trust any handicap number, confirm your league's basis score and percentage — they are not standardised, and using the wrong pair changes every game. Remember too that a bowler averaging at or above the basis receives zero handicap: the formula clamps negative results to 0. When in doubt, ask your league secretary, whose figures are the ones that count.
Frequently asked questions
Why do so many bowling handicap calculators give the wrong number?
Most of them round the average or the handicap to the nearest whole number. USBC rules truncate — they drop the decimal entirely. An average of 145.8 becomes 145, and a handicap of 67.5 becomes 67, not 68.
What basis score and percentage should I use?
Your league sets both. Common combinations are 90% or 100% of a basis of 200, 210 or 220. Check your league's rules or ask the league secretary — the numbers are not standardised across leagues.
What happens if my average is at or above the basis score?
Your handicap is zero. The formula clamps any negative result to 0, so a bowler averaging at or above the basis receives no handicap strokes.
Related tools and reading
Bowling Handicap calculator
Enter your total pins, games and league settings to get a USBC-correct, truncated handicap.
ReadHow scoring tables get revised
Why standards bodies update their basis figures and tables, and how the changes reach you.
Sources
- United States Bowling Congress, USBC Playing Rules — average, basis, percentage and the truncation rule for handicap calculation. Checked 24 Aug 2026.