MDT to ADT Converter
MDT to ADT, made simple. ADT is 3 hours ahead of MDT. Change the time or date in either card and the conversion follows along instantly.
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 Mountain Daylight Time (MDT).
MDT to ADT conversion chart
For example, a 9:00 AM MDT meeting takes place at 12:00 PM ADT. Concretely, when Denver (MDT) and Halifax (ADT) set up a call, aDT is 3 hours ahead of MDT.
| MDT time | ADT time |
|---|---|
| 12:00 AM | 3:00 AM |
| 1:00 AM | 4:00 AM |
| 2:00 AM | 5:00 AM |
| 3:00 AM | 6:00 AM |
| 4:00 AM | 7:00 AM |
| 5:00 AM | 8:00 AM |
| 6:00 AM | 9:00 AM |
| 7:00 AM | 10:00 AM |
| 8:00 AM | 11:00 AM |
| 9:00 AM | 12:00 PM |
| 10:00 AM | 1:00 PM |
| 11:00 AM | 2:00 PM |
| 12:00 PM | 3:00 PM |
| 1:00 PM | 4:00 PM |
| 2:00 PM | 5:00 PM |
| 3:00 PM | 6:00 PM |
| 4:00 PM | 7:00 PM |
| 5:00 PM | 8:00 PM |
| 6:00 PM | 9:00 PM |
| 7:00 PM | 10:00 PM |
| 8:00 PM | 11:00 PM |
| 9:00 PM | 12:00 AM+1 day |
| 10:00 PM | 1:00 AM+1 day |
| 11:00 PM | 2:00 AM+1 day |
This chart uses the fixed MDT and ADT offsets; the live converter above follows current daylight saving.
Convert MDT to ADT Time Zone
Everything you need for MDT to ADT — the difference, the current times, and how to plan around it.
Converting MDT to ADT, step by step
It takes three quick steps:
- Click the MDT field on the left and pick the time you want to convert.
- The matching ADT 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.
MDT vs ADT: what's the time gap?
ADT is 3 hours ahead of MDT. In everyday terms, once you know the time on one side you just add 3 hours to get the other — so a call between Denver and Halifax is always 3 hours apart.
What's the current time in ADT?
Right now the time in Atlantic Daylight Time (ADT) is Monday, June 29, 2026 · 2:53:56 PM. It ticks every second, so you’re always looking at the live ADT clock.
And what time is it in MDT?
And in Mountain Daylight Time (MDT), it’s currently Monday, June 29, 2026 · 11:53:56 AM. Compare the two and the 3 hours gap is easy to see.
What's the best time for a MDT–ADT call?
For example, a 9:00 AM MDT meeting takes place at 12:00 PM ADT. 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.
Does daylight saving time change the MDT–ADT difference?
The labels MDT and ADT 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 3 hours gap usually holds steady right through the year.
How accurate is this MDT to ADT conversion?
We don’t guess. MDT and ADT times are worked out from the official IANA time zone database, the trusted standard that operating systems use worldwide. Because daylight-saving rules and regional offsets do change over time, we track those updates rather than relying on a fixed number — which is exactly where many converters slip up.
Convert MDT 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
- 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
Convert to ADT from 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
- AST Atlantic Standard 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 ahead of MDT is ADT?
ADT is 3 hours ahead of MDT — a fixed 3 hours difference, since both are fixed-offset labels.
What time is it in ADT when it's 12:00 PM MDT?
When it's 12:00 PM (noon) MDT, it's 3:00 PM ADT.
Do MDT or ADT use daylight saving time?
Mountain Daylight Time (MDT) observes daylight saving, alternating with MST; Atlantic Daylight Time (ADT) observes daylight saving, alternating with AST.
Why might the real-world MDT–ADT difference change during the year?
The labels MDT and ADT are fixed offsets, so this converter is always exact. But Mountain Daylight Time's region switches between standard and summer time, so for part of the year you may actually want MST to ADT. Always check which label a region is currently using before you schedule.