Sports Statistics Formulas, Defined

Calculate a pitcher's earned run average from earned runs and innings pitched.

Source: Official Baseball Rules, Rule 9.15 (ERA)

Calculate a pitcher's WHIP (walks + hits per inning pitched) from walks, hits, and innings pitched.

Source: MLB Glossary — WHIP

Calculate batting average (AVG) from hits and at bats.

Source: MLB Glossary — Batting Average

Calculate OPS (on-base plus slugging) from hits, at bats, total bases, walks, hit by pitch, and sacrifice flies.

Source: MLB Glossary — OPS

Calculate fielding percentage (FPCT) from putouts, assists, and errors.

Source: MLB Glossary — Fielding Percentage (FPCT)

Calculate slugging percentage (SLG) from singles, doubles, triples, home runs, and at bats.

Source: MLB Glossary — Slugging Percentage (SLG)

Calculate on-base percentage (OBP) from hits, walks, hit by pitch, at bats, and sacrifice flies.

Source: MLB Glossary — On-Base Percentage (OBP)

Convert baseball innings pitched notation (.1/.2 for outs) into true decimal innings and total outs.

Source: MLB Glossary — Innings Pitched (IP)

Calculate a pitcher's strikeout-to-walk ratio (K/BB) from strikeouts and walks.

Source: MLB Glossary — Strikeout-to-Walk Ratio (K/BB)

Calculate a pitcher's walks per nine innings (BB/9) from walks allowed and innings pitched.

Source: MLB Glossary — Walks per Nine Innings (BB/9)

Calculate a pitcher's strikeouts per nine innings (K/9) from strikeouts and innings pitched.

Source: MLB Glossary — Strikeouts per Nine Innings (K/9)

Look up Little League pitch limits: the maximum pitches per day by league age and the required rest days from pitches thrown.

Source: Little League Baseball — Regular Season Pitching Rules (Regulation VI)

Calculate the NFL's official quarterback passer rating from completions, yards, touchdowns, and interceptions.

Source: Wolfram Formula Repository — Football Passer Rating

Calculate yards per carry (YPC) from rushing yards and carries.

Source: Pro-Football-Reference — Statistics Glossary

Calculate a quarterback's completion percentage from completions and attempts.

Source: Pro-Football-Reference — Statistics Glossary

Calculate a quarterback's yards per attempt (Y/A) from passing yards and attempts.

Source: Pro-Football-Reference — Statistics Glossary

Calculate true shooting percentage, the shooting-efficiency stat that accounts for free throws and threes.

Source: Basketball Reference — Glossary (TS%)

Calculate effective field goal percentage (eFG%) from field goals made, three-pointers made, and field goal attempts.

Source: Basketball Reference — Glossary (eFG%)

Calculate assist-to-turnover ratio (AST/TOV) from assists and turnovers.

Source: NBA.com — Stats Glossary

Calculate John Hollinger's Game Score (GmSc), a single-game efficiency score built from box score totals.

Source: Basketball Reference — Glossary (Game Score)

Calculate a goaltender's save percentage from saves and shots against.

Source: NHL Official Guide & Record Book — Goaltending Statistics

Calculate a goaltender's goals against average (GAA) from goals allowed and minutes played.

Source: NHL Official Guide & Record Book — Goaltending Statistics

Calculate a hockey player's plus/minus (+/-) from goals for and goals against while on the ice.

Source: Hockey Reference — Glossary (Plus/Minus)

Calculate a hockey player's points per game (P/GP) from goals, assists, and games played.

Source: Hockey Reference — Glossary (Points, Games Played)

Convert a Handicap Index into a Course Handicap for a specific course and tee, using the official World Handicap System formula.

Source: USGA — World Handicap System, Rule 6.1

Calculate a golf round's Score Differential from Adjusted Gross Score, Course Rating, and Slope Rating, using the official World Handicap System formula.

Source: USGA — World Handicap System, Rule 5.1

Calculate a golfer's Handicap Index from recent rounds' Score Differentials, using the official World Handicap System table and formula.

Source: USGA — World Handicap System, Rule 5.1

Calculate a golfer's scoring average from total strokes and rounds played.

Source: PGA TOUR — Stats Glossary (Scoring Average)

Calculate a soccer player's goals and assists per 90 minutes, the standard scouting stat for comparing output across playing time.

Source: FBref — Statistics Glossary (Per 90 Minutes stats)

Calculate a soccer player or team's pass completion percentage from completed and attempted passes.

Source: FBref — Statistics Glossary (Passing stats)

Calculate a soccer team or goalkeeper's clean sheet percentage from clean sheets and matches played.

Source: FBref — Statistics Glossary (Goalkeeping stats, CS%)

Calculate a soccer player or team's shot accuracy (shots on target percentage) from shots on target and total shots.

Source: FBref — Statistics Glossary (Shooting stats, SoT%)