user1475: Consider the transaction 948a427.. which has 3341 confirmations as of now:

We can see that the time the relay is received at 8:36:30 and it has one confirmation at 08:50:04 (after 14 minutes).
How do we find out the exact time when it has 3 confirmations?

user15524: As answered by Tim S. the 3rd confirmation is on block 298904. But the received time on blockchain.info is mostly inaccurate, see:
http://api.blockcypher.com/v1/btc/main/blocks/298902
http://api.blockcypher.com/v1/btc/main/blocks/298904
http://api.blockcypher.com/v1/btc/main/blocks/298905
So 298904 was received at 9:31:55 while 298905 was received at 9:32:04.

user12034: The first confirmation was in block 298902, so the third confirmation was with block 298904, which is timestamped as 2014-05-03 09:42:49 (66 minutes after it was first received).
However, this timestamp is later than the one in the block after it, suggesting that a timestamp was pretty far off. As Matthieu's answer shows, blockcypher.com's API includes the time that they first saw the transaction. This suggests that the actual time three confirmations was reached was around 2014-05-03T09:31:55.867Z, approximately 59 minutes after the transaction was created (since it was relayed by Blockchain.info, I'm assuming the transaction timestamp there is accurate).

1475: <p>Consider <a href="https://blockchain.info/tx/948a4275c9283110e915cbf51eec6831b4736b01dd2f10f084bb95e46aee1f36" rel="nofollow noreferrer">the transaction 948a427..</a> which has 3341 confirmations as of now:</p>

<p><img src="https://i.stack.imgur.com/kv2dA.png" alt="enter image description here"></p>

<p>We can see that the time the relay is received at 8:36:30 and it has one confirmation at 08:50:04 (after 14 minutes).</p>

<p>How do we find out the exact time when it has 3 confirmations?</p>
 15524: <p>As answered by Tim S. the 3rd confirmation is on block 298904. But the received time on blockchain.info is mostly inaccurate, see:</p>

<p><a href="http://api.blockcypher.com/v1/btc/main/blocks/298902" rel="nofollow">http://api.blockcypher.com/v1/btc/main/blocks/298902</a>
<a href="http://api.blockcypher.com/v1/btc/main/blocks/298904" rel="nofollow">http://api.blockcypher.com/v1/btc/main/blocks/298904</a>
<a href="http://api.blockcypher.com/v1/btc/main/blocks/298905" rel="nofollow">http://api.blockcypher.com/v1/btc/main/blocks/298905</a></p>

<p>So 298904 was received at 9:31:55 while 298905 was received at 9:32:04.</p>
 12034: <p>The first confirmation was in block 298902, so the third confirmation was with block <a href="https://blockchain.info/block/000000000000000004225c790dd5b4c448fba4ef5a147807ceae171ffe379bc6" rel="nofollow noreferrer">298904</a>, which is timestamped as 2014-05-03 09:42:49 (66 minutes after it was first received).</p>

<p>However, this timestamp is later than the one in the <a href="https://blockchain.info/block/00000000000000003b22a916695ea0cda213387101e1dc1d248beef9592bb091" rel="nofollow noreferrer">block after it</a>, suggesting that a timestamp was pretty far off. As <a href="https://bitcoin.stackexchange.com/a/25547/12034">Matthieu's answer</a> shows, <a href="http://www.blockcypher.com/" rel="nofollow noreferrer">blockcypher.com</a>'s API <a href="http://api.blockcypher.com/v1/btc/main/blocks/298904" rel="nofollow noreferrer">includes the time</a> that they first saw the transaction. This suggests that the actual time three confirmations was reached was around 2014-05-03T09:31:55.867Z, approximately 59 minutes after the transaction was created (since it was relayed by Blockchain.info, I'm assuming the transaction timestamp there is accurate).</p>
