To choose between EST and EDT for a time in New York, look at the date. From the first Sunday in November until the second Sunday in March the clock is on EST. In between it is on EDT. The abbreviation names the clock's current setting; it does not name a different place.
EST and EDT are the same clock with two seasonal names#
Eastern Standard Time (EST) is five hours behind Coordinated Universal Time, written UTC-5. UTC is the shared reference time that does not follow the seasons (UTC vs GMT: What Is the Difference and Which Should You Use?). Eastern Daylight Time (EDT) is UTC-4. Daylight saving time moves the clock ahead one hour in the warm months, so one city carries both names in a year.
| Name | Full name | UTC offset | When it applies in New York |
|---|---|---|---|
| EST | Eastern Standard Time | UTC-5 | First Sunday in November to the second Sunday in March |
| EDT | Eastern Daylight Time | UTC-4 | Second Sunday in March to the first Sunday in November |
The same wall-clock reading is a different instant under each name: 10:00 a.m. EDT in July is 14:00 UTC, while 10:00 a.m. EST in January is 15:00 UTC. Summer time is the longer season: in 2026 New York spends about 238 days on EDT and about 127 on EST. All figures here are computed from the IANA time zone database, version 2025b (as bundled with Node 22.22).
Which one applies today?#
The rule is federal law: daylight saving time starts at 2:00 a.m. on the second Sunday in March and ends at 2:00 a.m. on the first Sunday in November (15 U.S.C. § 260a; a Congressional Research Service report gives the same March-to-November span). Applied to the next two years, it gives these dates for New York:
| Year | Clocks go forward (EST to EDT) | Clocks go back (EDT to EST) |
|---|---|---|
| 2026 | Sunday, March 8: 2:00 a.m. EST becomes 3:00 a.m. EDT | Sunday, November 1: 2:00 a.m. EDT becomes 1:00 a.m. EST |
| 2027 | Sunday, March 14: 2:00 a.m. EST becomes 3:00 a.m. EDT | Sunday, November 7: 2:00 a.m. EDT becomes 1:00 a.m. EST |
October 9, 2026 is a Friday, so New York is on EDT, UTC-4, until the early hours of November 1. If the law changes, these dates change with it; When Do the Clocks Change? Daylight Saving Dates for 2026 and 2027 covers other regions and How Daylight Saving Time Works, Why It Exists and Who Still Uses It explains the mechanism.
To check without a calendar, look at the offset: UTC-4 for New York means EDT, and UTC-5 means EST. The Timelive EST page shows the current Eastern Time and says which of the two names the clock is on today.
Why ET is the safest way to write it#
ET stands for Eastern Time, whichever of EST or EDT the clock is on that day. It is right in January and in July because it does not commit to an offset. EST and EDT each commit to one: read literally, EST is a fixed UTC-5 and EDT a fixed UTC-4.
That matters when the label and the date disagree. Take an invitation that says "Wednesday, July 15, 2026, 10:00 a.m. EST". London is on British Summer Time (UTC+1) that day and Kolkata is on UTC+5:30.
| Reading | UTC | New York | London | Kolkata |
|---|---|---|---|---|
| New York's clock that day (10:00 a.m. EDT) | 14:00 | 10:00 a.m. | 3:00 p.m. | 7:30 p.m. |
| Literal EST (UTC-5) | 15:00 | 11:00 a.m. | 4:00 p.m. | 8:30 p.m. |
A reader may assume the sender meant New York's clock, but a person or program that takes "EST" literally lands an hour late. The reverse slip lands an hour early: "10:00 a.m. EDT" on January 15, 2026 is 14:00 UTC, which is 9:00 a.m. in New York.
EST and EDT are the right labels when the exact offset is the point, as in the repeated hour above. Abbreviations outside North America can clash across countries; IST, CST, PST: Why Time Zone Abbreviations Mean Different Things explains why.
The same pair exists in every US zone, and a few places skip it#
Each mainland zone has a standard name for winter and a daylight name for summer: CST and CDT for Central, MST and MDT for Mountain, PST and PDT for Pacific, and AKST and AKDT for Alaska. They switch at 2:00 a.m. local time on the same two Sundays in 2026 and 2027, so the gaps between them hold all year. New York is 3 hours ahead of Los Angeles in both January and July. US Time Zones Explained: Eastern, Central, Mountain, Pacific and Beyond has the full table and says which states fall in which zone.
Federal law lets a state opt out of daylight saving time, and Hawaii and most of Arizona have. Honolulu stays on HST (UTC-10) all year and Phoenix on MST (UTC-7), so their gap to New York changes by an hour twice a year: Phoenix is 2 hours behind in January and 3 hours behind in July, when noon in New York is 9:00 a.m. in Phoenix. The Navajo Nation, which reaches into Arizona, does observe daylight saving time, according to a 2016 Congressional Research Service report.
None of these places is in the Eastern zone, so EST and EDT do not apply to them. Unlike the New York slip above, "MST" written in Phoenix in July is correct.
How to write times in emails and invites#
- Use ET, CT, MT or PT with the date. "Wednesday, July 15, 10:00 a.m. ET" is clear in any month.
- Add UTC or a second city for anyone abroad. "10:00 a.m. ET (14:00 UTC)" removes the guesswork for readers who do not know the US season.
- Reserve EST and EDT for cases where the exact offset matters and you have checked which applies on that date.
- Do not mix standard and daylight labels. "9:00 a.m. PDT / noon EST" in July pairs a summer label with a winter one; "9:00 a.m. PT / noon ET" never mixes a summer label with a winter one.
- Remember recurring meetings. ET holds the New York wall-clock time fixed. A 10:00 a.m. ET meeting is 19:30 in Kolkata in July but 20:30 in January, because India does not change its clocks. EST to IST: Time Difference, Conversion Chart and Call Times has a chart, and How to Schedule a Meeting Across Time Zones: A 6-Step Checklist covers recurring meetings.
Frequently asked questions
Is New York on EST or EDT right now?
As of October 9, 2026, New York is on Eastern Daylight Time (EDT), UTC-4. The clocks go back one hour at 2:00 a.m. on Sunday, November 1, 2026, which puts the city on Eastern Standard Time (EST, UTC-5). Daylight time returns on Sunday, March 14, 2027.
What is the difference between EST and EDT?
One hour. EST is Eastern Standard Time, UTC-5, the winter setting. EDT is Eastern Daylight Time, UTC-4, the summer setting after the clocks move ahead.
Both name the same clock in places such as New York or Toronto. At any one instant, a clock on EDT reads one hour later than a clock on EST.
Should I write EST or ET?
Write ET if you mean Eastern Time on a particular date. It works year-round, whereas "EST" in July can be read as UTC-5, one hour away from New York's actual clock. Use EST or EDT only when you have checked which one applies on that date or must state the exact offset.
Which US states do not use daylight saving time?
Hawaii and most of Arizona do not change their clocks. The Navajo Nation, which reaches into Arizona, does observe daylight saving time. Several US territories, including Puerto Rico, Guam and American Samoa, also show no clock change in the IANA time zone data for 2026 and 2027. Because these places never move, their distance from New York changes by an hour each spring and autumn. US Time Zones Explained: Eastern, Central, Mountain, Pacific and Beyond lists them.
Is it wrong to say EST in the summer?
Strictly, yes: EST means UTC-5, but New York is at UTC-4 in summer. "EST" is often used loosely to mean "New York time", but a literal reader or program will be one hour off. Writing "ET" removes the problem, and adding a UTC time confirms the result.
Sources and further reading
- Daylight Saving Time (DST) — Congressional Research Service (via EveryCRSReport)
- Daylight Saving Time (CRS report R44411, 9 March 2016) — Congressional Research Service (via EveryCRSReport)
- Time zone and daylight saving time data — Internet Assigned Numbers Authority (IANA)