443 area code — Baltimore, MD geographic

Data: NANPA public reports, current as of July 28, 2026.

The 443 area code covers Baltimore, Maryland, Eastern time zone, and dates back to June 1, 1997. Together with 410, 667 it forms the 410/443/667 overlay. Because of number portability and VoIP, the area code tells you where the number was issued, not where the caller is right now.

NANPA lists 785 active NXX prefixes in 443, assigned to 26 carriers. 701 of those prefixes are pooled — shared between carriers in thousands-number blocks. The code spans 81 rate centers (billing localities).

Official projections put exhaust for the 410/443/667 complex at 1Q 2036.

The dialing plan is 10D for home-NPA local calls and 10D across codes.

Practical takeaway: the 443 label narrows geography to Maryland, the prefix narrows it to a locality, and neither authenticates a caller. Verification means calling back through a number you found yourself.

Its parent code is 410, which it left in 1997. Later relief produced 667 (2012) from its territory.

Largest localities in 443

FAQ

Why do 410 and 443 cover the same place?

They are overlays: when a code runs low on numbers, a new code is added over the same territory instead of splitting it. The 410/443/667 complex shares one service area, and local calls are dialed with 10 digits.

Will 443 run out of numbers?

NANPA's current forecast projects exhaust in 1Q 2036 — decades of capacity remain.

Why am I getting spam calls from 443 numbers?

Scammers spoof recognizable area codes so calls look local or familiar. A displayed 443 number does not prove the call originated there — see our guide to spotting spoofed calls.

Where is a 443 number from?

443 is assigned to Baltimore and surrounding areas of Maryland in the Eastern time zone. The three digits after the area code (the prefix) narrow it down to a rate center.

Is 443 a toll-free number?

No. 443 is a geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.