Home teams win more often in every sport, and baseball is no exception — but it has one of the smallest home edges anywhere. Regular-season home winning percentage by season: 2019 52.9%, 2020 55.0% (a 60-game season with no fans), 2021 53.9%, 2022 53.3%, 2023 52.1%, 2024 52.2%, 2025 54.3% and 2026 52.8%.
Where it comes from
Batting last is worth something (the home team knows exactly what it needs in the ninth), players sleep in their own beds, and each park's quirks favour a roster built for them. The 2020 season, played without crowds, did not remove the advantage, which suggests that crowd influence on umpires is a small part of it.
In the model
Home field is one input in the run model, fit from past seasons like everything else; on its own it is worth about half a percent of expected runs per team, and batting last is handled through the run distribution. Picking the home team in every game would have picked 52.9% of winners in our backtest — the model's 57.3% is measured against that baseline on the Methodology page.