CapitalOne is using the day after the date you have listed on your spreadsheet.
For example, for your first transaction of 43 SGD, you have a date of 12-Oct-2018. However, if you plug 13-Oct-2018 into Visa's Exchange Rate Calculator, you'll see that it gives you the same USD price as CapitalOne charged you.
The discrepancy in date might be related to the time difference, as you noted.
In my opinion, it is nothing to worry about. As you noted, it is just as likely as not to work in your favor. For cards that do have a foreign exchange fee, the fee averages 3%, and the difference you are seeing is nowhere close to that.
In response to your edit:
Please also explain why the three transactions on Nov 2nd have slightly different exchange rates even on my credit card statement.
All three of these transactions are using the exchange rate from November 3.
It appears that CapitalOne is using the real exchange rate for November 3 for each of these transactions. They then round to the nearest penny. Finally, for the exchange rate that appears on your statement, they calculate it for each transaction using the rounded amount that you were actually charged.
Example: The 11/2/2018 transaction of 30.00 SGD is converted to $21.902010 USD based on the 11/3/2018 rate. This is then rounded to $21.90, and is what you were charged on your credit card account. For the exchange rate listed on your statement, they simply calculated 30.00/21.90 = 1.369863014. Because of the rounding to the nearest penny, the exchange rates calculated on your statement in the last step are all slightly different from each other, but notice that all three of them are identical to the first three decimal places. Yes, it might be less confusing if they simply showed you the actual rate used in the first step, rather then back-calculating the rate after the rounding occurs, but that is the choice they made, and most people won't care.
Answer from Ben Miller on Stack ExchangeI was planning to make an online purchase from another country using my Venture X card. When I saw the converted amount in USD, it seemed a bit higher than expected based on the current exchange rate. Upon checking, I discovered that Capital One is charging a 6% currency conversion fee. I was under the impression that foreign transactions with VextureX didn’t have any fees.
Has anyone else experienced this, or am I missing something?
Capital one is supposed to have no foreign transaction fee. I get that Mastercard takes a small amount off the top (1% or less) but it seems capital one or maybe it’s MC is offering a terrible rate for usd to MXN conversion? I don’t seem to have this problem for USD to EUR transactions, only seem to be getting screwed over when it comes to USD to MXN
What CC from the US offers the best rate? Is this happening with other MC cards or is it just cap one? Wondering if visa is better.
For example I just made a 214 MXN purchase which at time of conversion is $11.03 and was charged $11.48. This is 4% extra
Traveling to Europe for 3months and I leave beginning of April. How should I go about getting cash? I have a Capital One account, both debit and cc, and an Amex just cc. Trying to figure out the best exchange situation. I’ll use my Amex cc primarily but for small things and tips I think I will need a few hundred to a thousand euros. Is it better to exchange with a bank here in the US or in Europe? Is there even an atm for me in Europe? I’m starting in Lisbon, then on to Madrid, Barcelona, Cannes, Florence, Naples. That’s just my first 6 weeks. I’m north after that. Thanks for the help in advance!