Learn Baseball
Plain-English explainers on stats, rules and terminology — understand what the numbers mean and how the game works.
Featured articles
What Is OPS in Baseball?
OPS combines on-base and slugging into one number. Here is what it measures and what counts as good.
6 min readWhat Does ERA Mean in Baseball?
Earned run average is the classic pitching stat. Learn how it is calculated and what separates a good ERA from a bad one.
5 min readWhat Is WHIP in Baseball?
WHIP measures how many baserunners a pitcher allows per inning. Here is how to read it.
5 min readWhat Is WAR in Baseball?
Wins Above Replacement rolls everything a player does into one number. We break down the components and the scale.
8 min readBaseball Abbreviations & Scorebook Codes
A searchable glossary of 80+ stat abbreviations and scorekeeping codes, from AVG to WP.
4 min readBaseball Terms & Slang, A–Z
From "ate him up" to "worm burner" — a plain-English glossary of 120+ baseball terms.
7 min readStat explainers & references
Plain-English guides to the numbers, plus two searchable glossaries.
- What Is OPS?On-base plus slugging, explained
- What Does ERA Mean?Earned run average, explained
- What Is WHIP?Baserunners per inning
- What Is Slugging Percentage?Measuring power per at-bat
- What Is OBP?How often a hitter reaches base
- What Is WAR?Wins above replacement
- Baseball AbbreviationsSearchable stat-code glossary
- Baseball Terms & SlangA–Z terms glossary