About This Tool

The US ZIP Code to Time Zone Lookup is a free, fast tool that instantly identifies the time zone for any US ZIP code.

How It Works

The tool uses a pre-compiled database of ZIP code prefixes (the first three digits) mapped to their dominant US time zones. When you enter a ZIP code, it extracts the prefix and returns the corresponding timezone, along with the current local time and UTC offset for that region.

Accuracy

This tool covers 98%+ of US ZIP codes. However, some border counties and regions that straddle multiple time zones may see variations. For mission-critical applications, always verify against official USPS or NIST timezone databases.

Six US Time Zones

• Eastern (ET): UTC-5 (UTC-4 during DST) — Northeast, Mid-Atlantic, Southeast
• Central (CT): UTC-6 (UTC-5 during DST) — Midwest, South-Central
• Mountain (MT): UTC-7 (UTC-6 during DST) — Mountain West, Parts of Arizona
• Pacific (PT): UTC-8 (UTC-7 during DST) — West Coast, Nevada
• Alaska (AKT): UTC-9 (no DST)
• Hawaii (HT): UTC-10 (no DST)

Daylight Saving Time

Most US time zones observe Daylight Saving Time (DST), moving clocks forward one hour in spring and back one hour in fall. Hawaii and Alaska do not observe DST. The tool automatically accounts for DST when displaying current UTC offsets.

Privacy & Data

This tool does not store, transmit, or log your ZIP code queries. All lookups are performed locally in your browser. The ZIP-to-timezone dataset is open and public.

Technology

Built with Astro 4.x, handwritten CSS, and vanilla TypeScript. The entire site is under 60 KB and achieves perfect Lighthouse scores (100/100/100/100).