Standards

Bowling Handicap Calculator

Work out your USBC bowling handicap from your average, using your league’s basis score and handicap percentage. The average and the handicap are truncated, not rounded — the detail most online calculators get wrong.

Definitions: USBC Playing Rules • Checked 24 Aug 2026

Enter your numbers

Presets:

Average input

From pins & games Enter average

Total pins

Games bowled

Basis score

Handicap percentage

Scratch series (optional)

Games in series

Basis and percentage are set by your league — commonly 90% or 100% of a 200, 210 or 220 basis. Your league’s rules are what count.

Handicap per game

Enter your average

Truncated average

Basis − average

Scratch series

Series w/ handicap

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How a USBC handicap is calculated

A bowling handicap levels the field so bowlers of different skill can compete fairly. It is a number of pins added to your scratch score, based on how far your average sits below a fixed basis score. The lower your average, the bigger your handicap. Both the average and the handicap are truncated to a whole number — never rounded up.

Average = total pins ÷ games bowled, TRUNCATED (drop the decimals) Handicap/game = (basis − average) × percentage, TRUNCATED to a whole pin if (basis − average) ≤ 0, handicap = 0 Series scratch = sum of the game scores Series w/ hcp = scratch + (handicap/game × games)

basis: the target score set by the league (e.g. 220)
average: your truncated per-game average
percentage: the league handicap factor (e.g. 90% = 0.90)

Why truncate instead of round?

Under USBC rules the average is the total pinfall divided by games with the fractional part dropped — 4,795 pins over 30 games is 159.83, which becomes an average of 159, not 160. The handicap is then truncated to a whole pin the same way. Calculators that round give a higher average and a smaller handicap, which is wrong under league play. This tool uses Math.floor at both steps so the result matches the score sheet.

Worked example: 159 average, 90% of 220

Average: 4,795 ÷ 30 = 159.83 → floor → 159
Difference: 220 − 159 = 61
Handicap/game: 61 × 0.90 = 54.9 → floor → 54 pins
Three-game series with a 540 scratch: 540 + (54 × 3) = 540 + 162 = 702

A bowler averaging above the 220 basis — say 225 — gets a handicap of 0, because (220 − 225) is negative. Handicaps are never negative.

Handicap per game at 90% of a 220 basis

Example handicaps across a range of averages, using the common league setting of 90% of a 220 basis. Each value is (220 − average) × 0.90, truncated to a whole pin. Change the basis or percentage above and the calculator updates.

Average	Basis − average	Handicap / game
120	100	90
140	80	72
160	60	54
180	40	36
200	20	18
210	10	9
220	0	0
230	−10	0

Accuracy notes and limits

Your league’s rules are the authority

Basis score and percentage are chosen by each league or tournament, so there is no single “correct” handicap — only the one your league’s rules define. Common settings are 90% or 100% of a 200, 210 or 220 basis. Some leagues also set a minimum number of games before a book average counts, or cap the handicap. This tool applies the standard USBC truncation, but always defer to your league secretary and the current USBC Playing Rules. This is an educational reference, not an official scoring service.

Frequently asked questions

Do I round the average or the handicap?

Neither — you truncate both. Drop the decimals on the average (159.83 becomes 159), then truncate the handicap to a whole pin (54.9 becomes 54). Rounding up is a common mistake that inflates scores.

What if my average is above the basis?

Your handicap is 0. Because (basis − average) is negative, the formula clamps to zero — handicaps are never negative.

What basis and percentage should I use?

Whatever your league sets. If you are unsure, 90% of 220 is a widely used default, but check your league’s rules — they govern.

Sources

United States Bowling Congress (USBC). Playing Rules — average and handicap definitions. bowl.com.