‘Same age’ needs a threshold
The Census Bureau’s 2025 result defines the group as partners within one year of each other. Pew’s historical marriage analysis uses two years or less. Both are reasonable, but they are not identical.
A page that says ‘same age’ without stating the window can make two valid studies look inconsistent when they simply use different definitions.
Close-age marriages increased since 2000
Pew found 51% of opposite-sex marriages were within two years in 2022, up from 46% in 2000. Over the same period, the average spousal age gap edged down from 2.4 to 2.2 years.
The longer historical comparison also shows a large decline from the average gap recorded in 1880, though household structure and social conditions changed substantially over that span.
Household data leave some couples out
Both sources require partners or spouses to be observed in the same household. Couples living apart are not part of the paired age calculation.
The finding also should not be converted into a preference claim. It describes formed couples, not swipe behavior or the full set of people each partner considered.