AST to CDT Converter
This page converts Atlantic Standard Time (AST) to Central Daylight Time (CDT). CDT is 1 hour behind AST, so a meeting at one time slides predictably to the other. Edit the time or date to begin.
Daylight saving notes
In the United States and Canada, daylight saving time runs from the second Sunday in March to the first Sunday in November. That affects Atlantic Standard Time (AST).
AST to CDT conversion chart
For example, a 9:00 AM AST meeting takes place at 8:00 AM CDT. Concretely, when Halifax (AST) and Chicago (CDT) set up a call, cDT is 1 hour behind AST.
| AST time | CDT time |
|---|---|
| 12:00 AM | 11:00 PM−1 day |
| 1:00 AM | 12:00 AM |
| 2:00 AM | 1:00 AM |
| 3:00 AM | 2:00 AM |
| 4:00 AM | 3:00 AM |
| 5:00 AM | 4:00 AM |
| 6:00 AM | 5:00 AM |
| 7:00 AM | 6:00 AM |
| 8:00 AM | 7:00 AM |
| 9:00 AM | 8:00 AM |
| 10:00 AM | 9:00 AM |
| 11:00 AM | 10:00 AM |
| 12:00 PM | 11:00 AM |
| 1:00 PM | 12:00 PM |
| 2:00 PM | 1:00 PM |
| 3:00 PM | 2:00 PM |
| 4:00 PM | 3:00 PM |
| 5:00 PM | 4:00 PM |
| 6:00 PM | 5:00 PM |
| 7:00 PM | 6:00 PM |
| 8:00 PM | 7:00 PM |
| 9:00 PM | 8:00 PM |
| 10:00 PM | 9:00 PM |
| 11:00 PM | 10:00 PM |
This chart uses the fixed AST and CDT offsets; the live converter above follows current daylight saving.
Convert AST to CDT Time Zone
Everything you need for AST to CDT — the difference, the current times, and how to plan around it.
How do I convert AST to CDT?
It takes three quick steps:
- Click the AST field on the left and pick the time you want to convert.
- The matching CDT time updates on the right automatically — there’s no button to press.
- Need a different day? Click the date field and the result follows, rolling over if it crosses midnight.
How many hours apart are AST and CDT?
CDT is 1 hour behind AST. In everyday terms, once you know the time on one side you just subtract 1 hour to get the other — so a call between Halifax and Chicago is always 1 hour apart.
What time is it in CDT right now?
Right now the time in Central Daylight Time (CDT) is Monday, June 29, 2026 · 12:53:57 PM. It ticks every second, so you’re always looking at the live CDT clock.
What time is it in AST right now?
And in Atlantic Standard Time (AST), it’s currently Monday, June 29, 2026 · 1:53:57 PM. Compare the two and the 1 hour gap is easy to see.
Planning a meeting across AST and CDT?
For example, a 9:00 AM AST meeting takes place at 8:00 AM CDT. The trick is to aim for a slot that lands inside normal working hours on both sides. Once you’ve found a time, hit Share on the converter to copy a link with the time built in — easy to send to a colleague. Juggling three or more zones? The meeting planner highlights the hours that overlap for everyone.
How does daylight saving affect AST to CDT?
The labels AST and CDT are fixed offsets, so the result on this page is always exact. Both regions move their clocks for daylight saving on roughly the same weekends, so the 1 hour gap usually holds steady right through the year.
Why can you trust this AST to CDT converter?
Every conversion here is calculated from the IANA time zone database — the same source your phone, computer, and browser rely on. Plenty of tools hard-code a single offset, which quietly goes wrong whenever a region changes its rules or flips for daylight saving. We follow the real rules instead, so AST to CDT stays accurate for today and for any past or future date you type in.
Convert AST to other time zones
- UTC Coordinated Universal Time
- GMT Greenwich Mean Time
- EST Eastern Standard Time
- EDT Eastern Daylight Time
- CST Central Standard Time
- CDT Central Daylight Time
- MST Mountain Standard Time
- MDT Mountain Daylight Time
- PST Pacific Standard Time
- PDT Pacific Daylight Time
- AKST Alaska Standard Time
- AKDT Alaska Daylight Time
- HST Hawaii Standard Time
- ADT Atlantic Daylight Time
- NST Newfoundland Standard Time
- NDT Newfoundland Daylight Time
- BRT Brasília Time
- ART Argentina Time
- WET Western European Time
- WEST Western European Summer Time
- CET Central European Time
- CEST Central European Summer Time
- EET Eastern European Time
- EEST Eastern European Summer Time
- BST British Summer Time
- IST Irish Standard Time
- MSK Moscow Standard Time
- TRT Turkey Time
- WAT West Africa Time
- CAT Central Africa Time
- EAT East Africa Time
- SAST South Africa Standard Time
- GST Gulf Standard Time
- IST Israel Standard Time
- IDT Israel Daylight Time
- IST India Standard Time
- PKT Pakistan Standard Time
- BDT Bangladesh Standard Time
- ICT Indochina Time
- WIB Western Indonesian Time
- WITA Central Indonesian Time
- WIT Eastern Indonesian Time
- CST China Standard Time
- HKT Hong Kong Time
- SGT Singapore Time
- PHT Philippine Time
- JST Japan Standard Time
- KST Korea Standard Time
- AWST Australian Western Standard Time
- ACST Australian Central Standard Time
- ACDT Australian Central Daylight Time
- AEST Australian Eastern Standard Time
- AEDT Australian Eastern Daylight Time
- NZST New Zealand Standard Time
- NZDT New Zealand Daylight Time
Convert to CDT from other time zones
- UTC Coordinated Universal Time
- GMT Greenwich Mean Time
- EST Eastern Standard Time
- EDT Eastern Daylight Time
- CST Central Standard Time
- MST Mountain Standard Time
- MDT Mountain Daylight Time
- PST Pacific Standard Time
- PDT Pacific Daylight Time
- AKST Alaska Standard Time
- AKDT Alaska Daylight Time
- HST Hawaii Standard Time
- AST Atlantic Standard Time
- ADT Atlantic Daylight Time
- NST Newfoundland Standard Time
- NDT Newfoundland Daylight Time
- BRT Brasília Time
- ART Argentina Time
- WET Western European Time
- WEST Western European Summer Time
- CET Central European Time
- CEST Central European Summer Time
- EET Eastern European Time
- EEST Eastern European Summer Time
- BST British Summer Time
- IST Irish Standard Time
- MSK Moscow Standard Time
- TRT Turkey Time
- WAT West Africa Time
- CAT Central Africa Time
- EAT East Africa Time
- SAST South Africa Standard Time
- GST Gulf Standard Time
- IST Israel Standard Time
- IDT Israel Daylight Time
- IST India Standard Time
- PKT Pakistan Standard Time
- BDT Bangladesh Standard Time
- ICT Indochina Time
- WIB Western Indonesian Time
- WITA Central Indonesian Time
- WIT Eastern Indonesian Time
- CST China Standard Time
- HKT Hong Kong Time
- SGT Singapore Time
- PHT Philippine Time
- JST Japan Standard Time
- KST Korea Standard Time
- AWST Australian Western Standard Time
- ACST Australian Central Standard Time
- ACDT Australian Central Daylight Time
- AEST Australian Eastern Standard Time
- AEDT Australian Eastern Daylight Time
- NZST New Zealand Standard Time
- NZDT New Zealand Daylight Time
Frequently asked questions
How many hours behind AST is CDT?
CDT is 1 hour behind AST — a fixed 1 hour difference, since both are fixed-offset labels.
What time is it in CDT when it's 12:00 PM AST?
When it's 12:00 PM (noon) AST, it's 11:00 AM CDT.
Do AST or CDT use daylight saving time?
Atlantic Standard Time (AST) observes daylight saving, alternating with ADT; Central Daylight Time (CDT) observes daylight saving, alternating with CST.
Why might the real-world AST–CDT difference change during the year?
The labels AST and CDT are fixed offsets, so this converter is always exact. But Atlantic Standard Time's region switches between standard and summer time, so for part of the year you may actually want ADT to CDT. Always check which label a region is currently using before you schedule.