ZIP code 02138

ZIP 02138 is a small city in Middlesex County, Massachusetts, with 38,077 residents counted in the Census American Community Survey 2019-2023 ACS 5-year estimates, which places it #33 of 539 ranked by population — larger than 94% of them. The median age here is 28.7 years against 39.1 nationally, a distinctly younger profile, typical of places with students, military posts or a fast-growing family population. Places under 65,000 residents only appear in the five-year release, never the one-year file, so these values pool sixty months of responses and lag the current year by design.

Households in ZIP 02138 earn a median of $122,040 a year, 55.4% above the national figure of $78,538. Household income here is measured before tax and pooled across everyone at the address, which is why it reads higher than typical individual earnings in the same area. Poverty reaches 12.6% of residents here, above the 12.4% national rate.

The typical owner-occupied home in ZIP 02138 is valued at $1,088,700, 258.8% above the national figure, while median gross rent runs $2,799 a month, 99.1% above the national figure, or roughly $33,588 across a full year. A household on the local median income would put about 27.5% of gross pay toward that rent against the federal 30% cost-burden threshold, so renting here is within the standard affordability guideline. The home-price-to-income ratio works out to 8.9×, against roughly 3.9× nationally, so buying is out of reach on local earnings alone and the ownership market leans on outside income, equity or dual high earners. 40.9% of occupied homes are owner-occupied versus 65% nationally, a renter-majority market, so rent figures matter more here than the home-value line. Gross rent folds in the utilities a tenant pays separately, so it is closer to the real monthly outlay than a headline rent figure.

Home values sit at 8.9× median household income, far past the 3.9× national mark, so ownership costs here are set by something other than local wages — second homes, retirees with equity, or commuters earning elsewhere. A median age of 28.7 means a large student or early-career population; income medians in places like this understate household resources, since many residents are supported from outside the address.

All values below were released by the Census for this exact geography, with no gap-filling on our side. Small-area estimates still carry wider margins of error than state or national figures, so check the linked ACS tables before relying on them for lending, appraisal or legal work.

ZIP 02138 is tabulated inside Middlesex County, Massachusetts, one of 81 ZIP areas the Census publishes for that county and 539 across Massachusetts. This is a dense urban ZIP, where a single postal boundary can hold more residents than an entire rural county. County assignment on this page follows the largest share of the ZIP's land area, which matters where a delivery route crosses a county line: mail addressed to 02138 can be handled by a post office in a neighbouring county even though the tabulation area is filed here.

Against its own county, 02138 reports a median household income of $122,040, 11% below the $136,382 county median, and 14% above the $107,198 typical MA ZIP. Owner-occupied homes are valued at a median of $1,088,700, 56% above the county figure and 126% above the statewide ZIP median. Rent is reported gross — the contract amount plus tenant-paid utilities — at $2,799 a month, which is why it reads higher than the advertised rent on a listing for the same unit.

Massachusetts charges 6.25% statewide, and no local sales tax is layered on top, so the state rate is the full amount collected in 02138.

Everything above comes from the Census Bureau American Community Survey 2019-2023 ACS 5-year estimates for this ZIP Code Tabulation Area, with sales tax rates traced to the state revenue agency. Five-year estimates pool sixty months of responses, so they are stable enough to compare 02138 with its neighbours but always trail the current year, and any value the Census suppressed for sample size is shown as unpublished rather than filled in with a model.