521 area code — NANP AREA non-geographic

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

Scope
Non-geographic
Time zone
Eastern
In service since
2017-09-21
Split from
500
Overlay complex
500 / 521 / 522 / 523 / 524 / 525 / 526 / 527 / 528 / 529 / 532 / 533 / 538 / 542 / 544 / 566 / 577 / 588

The 521 area code covers NANP AREA, Eastern time zone, and dates back to September 21, 2017. It is part of the 500/521/522/523/524/525/526/527/528/529/532/533/538/542/544/566/577/588 overlay complex — these codes share the same territory. Note that porting and VoIP mean a 521 number can be used from anywhere — the code marks where the number was assigned.

521 was created from 500 in 2017.

If a 521 call asks for money or personal data, treat the displayed number as unverified: hang up and reach the organization through its published number. Numbering data locates numbers, not callers.

Unlike geographic area codes, 521 serves non-geographic services across the whole NANP. There is no territory, no rate centers, and no carrier prefix table to show — the code exists at the numbering-plan level only.

FAQ

Is 521 a toll-free number?

No. 521 is a non-geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.

Why do 500 and 521 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 500/521/522/523/524/525/526/527/528/529/532/533/538/542/544/566/577/588 complex shares one service area, and local calls are dialed with 10 digits.

Why am I getting spam calls from 521 numbers?

Scammers spoof real area codes so calls look legitimate. A displayed 521 number does not prove the call originated there — see our guide to spotting spoofed calls.

Where is a 521 number from?

521 is assigned to NANP AREA in the Eastern time zone. The three digits after the area code (the prefix) narrow it down to a rate center.