Guide · Situational Factors

MLB Park Factors Betting Guide

Not every ballpark plays the same game. Here's what park factor actually measures, and the run environment for all 30 MLB stadiums.

What a park factor measures

A park factor is an index, centered on 1.00, that describes how many runs a ballpark tends to produce relative to a league-average park — accounting for things like outfield dimensions, altitude, foul territory, and typical wind patterns. A park factor of 1.07 means that stadium historically sees roughly 7% more runs scored than average; 0.93 means roughly 7% fewer. It isn't a guarantee for any single game, but it's a real, persistent bias that's worth building into any total-runs projection.

All 30 MLB ballparks' run environment

Run factors above are the same reference values used in LyDia's own total-runs model, expressed as an index around 1.00 (league average). Treat these as directional, persistent tendencies, not a fixed adjustment for any single game.

Why Coors Field is in a category of its own

Denver's altitude (roughly a mile above sea level) means thinner air, which reduces drag on batted balls and lets fly balls travel noticeably farther than at sea-level parks. It's the single most extreme park effect in the sport and the textbook example of why totals models need a park adjustment at all — a total that looks high relative to league average can still be underpriced for a game at Coors Field specifically.

Roofed stadiums still have a park factor

A closed roof removes weather as a game-day variable, but the stadium's dimensions and typical air density still create a real park effect — several of the more pitcher-friendly parks in the league (Miami, Seattle, Houston) have retractable or fixed roofs, and their factors reflect the ballpark itself, not just weather.

How to use this when betting totals

Park factor should adjust a total-runs projection multiplicatively — a projected 8.5-run environment at a neutral park becomes meaningfully higher at Coors and meaningfully lower at Oracle Park or Petco Park, all else equal. It's one input among several (team scoring rates, starting pitching, weather for open-air parks), not a standalone signal — see pitching metrics for betting and bullpen fatigue for the other major pieces of a totals projection.

Frequently asked questions

What does a park factor of 1.05 mean?

A park factor of 1.05 means that ballpark produces roughly 5% more runs than a league-average park, all else equal. A factor of 0.95 means roughly 5% fewer runs than average.

Which MLB park has the most extreme run environment?

Coors Field in Colorado, by a wide margin, due to its mile-high altitude reducing air density and letting the ball travel farther — commonly modeled around a 1.15-1.20 run factor, well above every other park in the league.

Do roofed stadiums still have park factors?

Yes, though weather stops being a game-day variable when the roof is closed. Dimensions, altitude, and typical air density inside the dome still create a real, if usually more moderate, park effect.

Related reading: Bullpen fatigue and betting · Pitching metrics for betting · Run line vs. moneyline