CHST to EST Converter

CHST to EST Time Difference

The standard time difference between Chamorro Standard Time (CHST) and Eastern Standard Time (EST) is exactly 15 hours. CHST operates at UTC+10 while EST operates at UTC-5. Since Chamorro Standard Time does not observe daylight saving time, its offset never changes. However, Eastern Time in the United States does observe DST, switching to Eastern Daylight Time (EDT, UTC-4) from the second Sunday in March to the first Sunday in November. During the EDT period, the gap narrows to 14 hours.

Here are practical conversion examples during Eastern Standard Time (November through March):

• Example 1: 12:00 AM CHST → 9:00 AM EST previous day. Subtracting 15 hours from midnight takes the time back to the previous morning.
• Example 2: 6:00 AM CHST → 3:00 PM EST previous day. An early-morning time in Guam corresponds to mid-afternoon on the day before in New York.
• Example 3: 12:00 PM CHST → 9:00 PM EST previous day. Noon in Guam is still the previous evening in the Eastern US.
• Example 4: 3:00 PM CHST → 12:00 AM EST same day. Afternoon in Guam is exactly midnight at the start of the same calendar day in New York.
• Example 5: 6:00 PM CHST → 3:00 AM EST same day. Evening in Guam is the early hours of the same date in the Eastern US.
• Example 6: 11:00 PM CHST → 8:00 AM EST same day. Late night in Guam is that morning in New York.

How to Convert CHST to EST

Converting from Chamorro Standard Time to Eastern Standard Time requires careful attention to both the hour offset and the calendar date. Follow these steps:

1. Determine the current CHST time: Start with the exact date and time in Chamorro Standard Time (UTC+10).
2. Check the Eastern Time season: Identify whether the target date falls during EST (November–March) or EDT (March–November) in the US.
3. Subtract the correct offset: Subtract 15 hours for EST or 14 hours for EDT.
4. Check the calendar date: If the subtracted result is a negative hour, add 24 hours and move the date back by one day. Most CHST-to-EST conversions result in the previous calendar day.

CHST to EST Conversion Table (Standard Time)

This table shows every hour of the day converted from Chamorro Standard Time to Eastern Standard Time (UTC-5). This applies during the EST period, roughly November through early March.

CHST to Eastern Time During Daylight Saving Time

When the US Eastern Time zone observes daylight saving time (the second Sunday in March through the first Sunday in November), clocks move forward one hour from EST (UTC-5) to EDT (UTC-4). This reduces the time gap between Guam and the Eastern US from 15 hours to 14 hours. The table below shows CHST-to-EDT conversions:

Common CHST to EST Conversions

Whether you are scheduling a business call from Guam to New York or tracking deliveries across the Pacific, these common conversions cover the most frequently searched times. Note how early CHST hours convert to the previous day in EST, while later CHST hours land on the same calendar day.

What Is CHST?

CHST stands for Chamorro Standard Time. It is the official time zone of the United States territories of Guam and the Commonwealth of the Northern Mariana Islands (CNMI), including Saipan, Tinian, and Rota. CHST operates at a fixed offset of UTC+10 throughout the entire year. The name "Chamorro" derives from the indigenous Chamorro people of the Mariana Islands. Because these Pacific islands sit close to the equator, daylight hours remain consistent year-round, eliminating any need for daylight saving time adjustments. The IANA timezone database identifies this zone as Pacific/Guam.

What Is EST?

EST stands for Eastern Standard Time (UTC-5). It is the standard-time designation for the US Eastern Time zone, which covers major cities like New York, Washington D.C., Miami, Atlanta, and Toronto in Canada. EST is in effect from the first Sunday in November through the second Sunday in March. During the remaining months, the region switches to Eastern Daylight Time (EDT, UTC-4). The IANA timezone identifier for Eastern Time is America/New_York. For a deeper understanding, explore our guide to Eastern Standard Time.

What Is EDT?

EDT stands for Eastern Daylight Time (UTC-4). It is observed from the second Sunday in March through the first Sunday in November in US states that participate in daylight saving time. During EDT, clocks are set one hour ahead of EST, which means the CHST-to-Eastern-Time difference shrinks from 15 hours to 14 hours. This seasonal shift is critical for accurate timezone conversion. Learn more in our detailed EST vs EDT comparison.

CHST vs EST Comparison

CHST vs Eastern Time

"Eastern Time" is the broader seasonal term that encompasses both EST and EDT. Because CHST never changes its offset, the time difference with Eastern Time fluctuates depending on the season:

Our converter automatically detects which offset to use based on the date you select. You never need to manually check whether EST or EDT is active.

Does CHST Observe Daylight Saving Time?

No. Chamorro Standard Time remains fixed at UTC+10 every single day of the year. Guam and the Northern Mariana Islands are located near the equator (approximately 13°N latitude), where the length of daylight barely fluctuates between summer and winter. This geographic reality eliminates any practical benefit from clock adjustments. When you see "CHST," it always means UTC+10—no exceptions.

Does Eastern Time Observe Daylight Saving Time?

Yes. Most of the US Eastern Time zone participates in daylight saving time. Clocks spring forward one hour on the second Sunday in March (moving from EST to EDT) and fall back one hour on the first Sunday in November (returning from EDT to EST). Notable exceptions include parts of Indiana that historically did not observe DST, though most Indiana counties now follow the standard Eastern Time DST schedule. This seasonal switch directly impacts CHST-to-Eastern-Time conversions, changing the offset from −15 hours to −14 hours.

CHST to EDT

During the Eastern Daylight Time period (typically mid-March through early November), the formula becomes:

For example, 10:00 AM CHST converts to 8:00 PM EDT on the previous calendar day (10 minus 14 = -4, plus 24 = 20:00 = 8:00 PM, and the date moves back one day). Meanwhile, 6:00 PM CHST becomes 4:00 AM EDT on the same calendar day (18 minus 14 = 4:00 AM).

CHST to US Eastern Time

In practical terms, converting between Guam (CHST, Pacific/Guam) and the US East Coast (America/New_York) is most relevant for:

• US Military personnel: Guam hosts Andersen Air Force Base and Naval Base Guam. Service members and their families communicate frequently with Washington D.C. and other Eastern Time locations.
• Federal government operations: As a US territory, Guam coordinates with federal agencies headquartered in the Eastern Time zone.
• Business and logistics: Shipping, aviation, and telecommunications between the Western Pacific and the Eastern US require precise time coordination.
• Tourism and travel: Visitors from the US East Coast planning trips to Guam need to understand the dramatic time shift for flight scheduling and jet lag management.

Guam Time vs Eastern Time

Guam uses Chamorro Standard Time (CHST, UTC+10) year-round. New York, the primary reference city for Eastern Time, alternates between EST (UTC-5) and EDT (UTC-4). The practical implications are significant:

• When it is Monday 10:00 AM in Guam, it is Sunday 7:00 PM EST in New York (during standard time).
• When it is Wednesday 2:00 PM in Guam, it is Tuesday 11:00 PM EST (during standard time) or Wednesday 12:00 AM EDT (during daylight time).
• Guam is essentially "almost a full day ahead" of the Eastern US. This makes real-time collaboration challenging but enables effective follow-the-sun workflows.

For more timezone comparisons, check our guide to how time zones work.

Does CHST to EST Change the Date?

Yes—and it happens most of the time. Because CHST is 15 hours ahead of EST, the majority of CHST hours convert to the previous calendar day in EST. The date boundary occurs at 3:00 PM CHST:

• 12:00 AM – 2:59 PM CHST: These 15 hours all convert to the previous calendar day in EST.
• 3:00 PM – 11:59 PM CHST: These 9 hours convert to the same calendar day in EST.

For example, if you send an email at 10:00 AM CHST on a Wednesday, it arrives in a New York inbox timestamped 7:00 PM EST on Tuesday. During EDT, the crossover shifts to 2:00 PM CHST (since 14 hours behind instead of 15).

Best CHST to Eastern Time Meeting Times

Practical Uses of CHST to EST Conversion

Frequently Asked Questions: CHST to EST