The zip code 21012 in Arnold, Maryland, is classified as a "White Majority" community as of 2022, with a median income of $125,243. The area has shown signs of increasing diversity over the past decade. From 2013 to 2022, Arnold has maintained its status as a "White Majority" community, but there is a clear trend towards increased diversity. The white population decreased from 87% in 2013 to 76% in 2022. The Hispanic population increased from 4% to 9%, and the Black population rose from 2% to 5%. The Asian population remained relatively stable at 3%, while the population identifying as two or more races increased from 1% to 6%.

These demographic shifts indicate movement towards potentially moderate diversity in the coming years if current trends continue. The median income in Arnold has shown an overall upward trend, rising from $115,933 in 2013 to $125,243 in 2022, an increase of about 8%. This growth in median income has occurred alongside the increasing diversity. The population has also grown from 21,514 in 2013 to 23,622 in 2022, an increase of about 9.8%.

The median household income in Arnold ($125,243 in 2022) is significantly higher than the national median ($70,784 in 2021), indicating that this is a relatively affluent area. The increasing diversity in Arnold aligns with broader national trends of growing diversity in suburban areas, particularly those near major metropolitan centers.