Ziptz

Get time zone, daylight saving time, and base offset for any US ZIP code.

ZIP codes are up to date as of May 2024.

Compatibility

Ziptz is tested to work with the following versions of Ruby:

• Ruby 3.3.x, 3.4.x, 4.0.x

Installation

Add the gem to your Gemfile:

gem 'ziptz'

Data File Requirement

Starting with version 6.0.0, you'll need to supply your own time zone SQLite database file. You can subscribe to the required dataset here: ZIP Code Time Zones Dataset

Usage

First, initialize Ziptz with the path to your time zone database file:

z = Ziptz.new('/path/to/your/tz.db')
# or using keyword argument
z = Ziptz.new(db: '/path/to/your/tz.db')

Get the time zone name for any ZIP code:

z.time_zone_name('97213') #=> "America/Los_Angeles"

ZIP codes may be passed as strings or integers. Integers are zero-padded to 5 digits, and 9-digit ZIP+4 strings are truncated to their first 5 digits:

z.time_zone_name(601)          #=> "America/Puerto_Rico" (looks up 00601)
z.time_zone_name('97213-4704') #=> "America/Los_Angeles"

Get the time zone offset for any ZIP code:

z.time_zone_offset('97213') #=> -28800

Note that offsets do not include daylight saving time.

Determine if the ZIP code uses Daylight Saving Time:

z.time_zone_uses_dst?('97213') #=> true

Get all the zip codes in a time zone:

z.zips('Pacific/Chuuk') #=> ["96942", "96943"]

Lookups for unknown, invalid, or nil ZIP codes raise Ziptz::ZipNotFound (since version 6.1.0; earlier versions returned nil):

z.time_zone_name('00000') #=> raises Ziptz::ZipNotFound

Database connections are opened lazily and cached per thread. Call close to close the current thread's connection; the next lookup reopens it automatically:

z.close

Supported Time Zones

• America/Adak
• America/Anchorage
• America/Boise
• America/Chicago
• America/Denver
• America/Detroit
• America/Indiana/Indianapolis
• America/Indiana/Knox
• America/Indiana/Marengo
• America/Indiana/Petersburg
• America/Indiana/Tell_City
• America/Indiana/Vevay
• America/Indiana/Vincennes
• America/Indiana/Winamac
• America/Juneau
• America/Kentucky/Louisville
• America/Kentucky/Monticello
• America/Los_Angeles
• America/Menominee
• America/Metlakatla
• America/New_York
• America/Nome
• America/North_Dakota/Beulah
• America/North_Dakota/Center
• America/North_Dakota/New_Salem
• America/Phoenix
• America/Puerto_Rico
• America/Sitka
• America/St_Thomas
• America/Yakutat
• Pacific/Chuuk
• Pacific/Guam
• Pacific/Honolulu
• Pacific/Kosrae
• Pacific/Kwajalein
• Pacific/Majuro
• Pacific/Pago_Pago
• Pacific/Palau
• Pacific/Pohnpei
• Pacific/Saipan
• Pacific/Wake

Note that APO/FPO zip codes will not return a known time zone offset.

Prefer raw data?

If you would prefer raw data instead of a gem, see my ZIP Code Time Zones product on AWS Data Exchange to subscribe.

Version 3 breaking changes

• APO, DPO, and FPO zip codes are no longer included, because they are non-geographic.
• Time zone offsets are now specified in seconds instead of hours.
• Time zone are now more granular. The full list of time zones is:
  • America/Adak
  • America/Anchorage
  • America/Boise
  • America/Chicago
  • America/Denver
  • America/Detroit
  • America/Indiana/Indianapolis
  • America/Indiana/Knox
  • America/Indiana/Marengo
  • America/Indiana/Petersburg
  • America/Indiana/Tell_City
  • America/Indiana/Vevay
  • America/Indiana/Vincennes
  • America/Indiana/Winamac
  • America/Juneau
  • America/Kentucky/Louisville
  • America/Kentucky/Monticello
  • America/Los_Angeles
  • America/Menominee
  • America/Metlakatla
  • America/New_York
  • America/Nome
  • America/North_Dakota/Beulah
  • America/North_Dakota/Center
  • America/North_Dakota/New_Salem
  • America/Phoenix
  • America/Puerto_Rico
  • America/Sitka
  • America/St_Thomas
  • America/Yakutat
  • Pacific/Chuuk
  • Pacific/Guam
  • Pacific/Honolulu
  • Pacific/Kosrae
  • Pacific/Kwajalein
  • Pacific/Majuro
  • Pacific/Pago_Pago
  • Pacific/Palau
  • Pacific/Pohnpei
  • Pacific/Saipan
  • Pacific/Wake

Version 2 breaking changes

Time zone names now reflect standard tz-database names.

V1 Name	V2 Name
Atlantic	America/Puerto_Rico
Eastern	America/New_York
Central	America/Chicago
Mountain	America/Denver
Pacific	America/Los_Angeles
Hawaii-Aleutian Islands	Pacific/Honolulu or America/Adak
American Samoa	Pacific/Pago_Pago
Marshall Islands	Pacific/Majuro
Guam	Pacific/Guam
Palau	Pacific/Palau
Micronesia	Pacific/Pohnpei

License

Copyright (c) 2015-2026 Keith Morrison <<keithm@infused.org>>

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.