--:--:--
—
San Juan · Barbados · Halifax (winter)
For international scheduling, try the global meeting planner.
Difference
CDT vs AST
UTC → UTC
--:--:--
—
Chicago · Houston · Dallas
AST to CDT converter
Convert AST to CDT time now
Free AST to CDT converter. See Atlantic Standard Time and Central Daylight Time side by side. Live clocks, a 1 hour gap, meeting hours, and a full-day chart for San Juan and Chicago.
America/Puerto_Rico
—
AST → CDT
To · Central Daylight Time
—
America/Chicago
Interactive diagram
Watch AST convert into CDT
Drag the Atlantic hour. Watch the Central DT clock change.
Atlantic
9:00 AM AST
—
CDT ← AST
Central DT
—
Full-day chart
AST to CDT hourly conversion chart
Full-day table. Tap a row to copy. Labels follow daylight saving.
| Atlantic | Central DT | UTC offsets |
|---|
Meeting times
Best AST to CDT meeting window
Find hours that work on both sides. Then save the slot to your calendar.
Follow along
Step-by-step AST to CDT conversion
Four short steps to convert any AST time to CDT.
Choose AST time
Select any hour in Atlantic Standard Time. Smart mode uses America/Puerto_Rico.
AST to CDT conversion guide
AST to CDT conversion guide
This AST to CDT converter shows Central Daylight Time (UTC−5) for any Atlantic Standard Time (UTC−4) time. Use it to schedule between San Juan and Chicago. Choose Smart DST for live city clocks. Choose Fixed mode when you only want the AST and CDT labels.
Atlantic
AST
UTC−4
San Juan · Barbados · Halifax (winter)
AST vs CDT—
Central DT
CDT
UTC−5
Chicago · Houston · Dallas
What is AST to CDT conversion?
AST to CDT conversion turns a AST clock into the matching CDT time. Use it for calls, travel, and teams in San Juan and Chicago.
AST to CDT time difference
CDT is 1 hour behind AST. Subtract 1 hour from the AST time to get CDT. The live clocks at the top show the current AST to CDT gap.
AST vs CDT
AST is UTC−4. CDT is UTC−5. They are different names. If a region uses daylight saving, check the live labels.
AST to CDT now / current time
Need ast to cdt right now? Read the live clocks, or tap Use current time for an instant AST → CDT result.
AST to CDT time difference
Season / context — tap to explore
See how daylight saving can change this pair.
Atlantic—
—AST → CDT
Central DT—
Quick answers
Atlantic
Atlantic Standard Time (AST)
UTC−4
Atlantic Standard Time (AST) is UTC−4. Smart DST uses the city clock America/Puerto_Rico so daylight saving stays correct for San Juan · Barbados · Halifax (winter).
- Cities: San Juan · Barbados · Halifax (winter)
- City clock: America/Puerto_Rico
- Fixed AST: UTC−4
- On this page it pairs with CDT (UTC−5)
Central DT
Central Daylight Time (CDT)
UTC−5
Central Daylight Time (CDT) is UTC−5. Smart DST uses America/Chicago for cities such as Chicago · Houston · Dallas.
- Cities: Chicago · Houston · Dallas
- City clock: America/Chicago
- Fixed CDT: UTC−5
- From AST: CDT is 1 hour behind AST
AST to CDT FAQ