built:date

IST to AST Converter

From India Standard Time to Atlantic Standard Time: aST is 9 hours and 30 minutes behind IST. Use the editable converter to translate any IST time — including the date — into AST.

ADT is 8 hours 30 min behind IST
From
IST

Now in Kolkata: 11:24:01 PM IST

To
ADT

Now in Halifax: 2:54:01 PM ADT

On this date Halifax observes ADT. AST is in effect during standard-time (non-summer) months.

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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).

IST to AST conversion chart

For example, a 9:00 AM IST meeting takes place at 11:30 PM AST (−1 day). Concretely, when Mumbai (IST) and Halifax (AST) set up a call, aST is 9 hours and 30 minutes behind IST.

India Standard Time to Atlantic Standard Time conversion chart
IST timeAST time
12:00 AM2:30 PM−1 day
1:00 AM3:30 PM−1 day
2:00 AM4:30 PM−1 day
3:00 AM5:30 PM−1 day
4:00 AM6:30 PM−1 day
5:00 AM7:30 PM−1 day
6:00 AM8:30 PM−1 day
7:00 AM9:30 PM−1 day
8:00 AM10:30 PM−1 day
9:00 AM11:30 PM−1 day
10:00 AM12:30 AM
11:00 AM1:30 AM
12:00 PM2:30 AM
1:00 PM3:30 AM
2:00 PM4:30 AM
3:00 PM5:30 AM
4:00 PM6:30 AM
5:00 PM7:30 AM
6:00 PM8:30 AM
7:00 PM9:30 AM
8:00 PM10:30 AM
9:00 PM11:30 AM
10:00 PM12:30 PM
11:00 PM1:30 PM

This chart uses the fixed IST and AST offsets; the live converter above follows current daylight saving.

Convert IST to AST Time Zone

A quick guide to IST → AST: the time gap, the live clocks, scheduling tips, and how we keep it accurate.

Converting IST to AST, step by step

It takes three quick steps:

  1. Click the IST field on the left and pick the time you want to convert.
  2. The matching AST time updates on the right automatically — there’s no button to press.
  3. Need a different day? Click the date field and the result follows, rolling over if it crosses midnight.

IST vs AST: what's the time gap?

AST is 9 hours and 30 minutes behind IST. In everyday terms, once you know the time on one side you just subtract 9 hours 30 min to get the other — so a call between Mumbai and Halifax is always 9 hours 30 min apart.

What's the current time in AST?

Right now the time in Atlantic Standard Time (AST) is Monday, June 29, 2026 · 1:54:01 PM. It ticks every second, so you’re always looking at the live AST clock.

And what time is it in IST?

And in India Standard Time (IST), it’s currently Monday, June 29, 2026 · 11:24:01 PM. Compare the two and the 9 hours 30 min gap is easy to see.

When is a good time to schedule a IST to AST meeting?

For example, a 9:00 AM IST meeting takes place at 11:30 PM AST (−1 day). 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 IST–AST difference?

The labels IST and AST are fixed offsets, so the result on this page is always exact. One side switches between standard and summer time while the other stays put, so the real-world gap can shift by an hour for part of the year. It's worth checking which label a region is actually using before you lock in a time.

How accurate is this IST to AST conversion?

We don’t guess. IST and AST 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 IST to other time zones

Convert to AST from other time zones

Frequently asked questions

How many hours behind IST is AST?

AST is 9 hours and 30 minutes behind IST — a fixed 9 hours and 30 minutes difference, since both are fixed-offset labels.

What time is it in AST when it's 12:00 PM IST?

When it's 12:00 PM (noon) IST, it's 2:30 AM AST.

Do IST or AST use daylight saving time?

India Standard Time (IST) is a fixed offset with no daylight saving; Atlantic Standard Time (AST) observes daylight saving, alternating with ADT.

Why might the real-world IST–AST difference change during the year?

The labels IST and AST 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 IST to ADT. Always check which label a region is currently using before you schedule.