The easy way to convert date formats
When you get data from other systems (or other countries), you will invariably run into a problem with incompatible date formats. With Nextanalytics for Excel, you can easily adapt to any incoming date format without much effort — and no formulas!
When you load a file into Nextanalytics for Excel, your incoming columns are listed, showing how Excel will interpret them. If you have a date column, and it is not identified as a date, then it probably has an incompatible format. Simply drag the name of the date column from the Incoming box to the Rows box; the contents of the column will be shown in the worksheet in the background.

Switch to the Options tab, and in the Incoming Date Format box, match the characters appropriate for the dates you see in the worksheet. If you click on the Date Help button, a popup will appear with some of the codes possible, as well as a couple of web references you can use for more descriptions (see examples below).

Once you have entered the new format, click the Pivot tab to see how they are interpreted. You will see the column name in blue with a ‘(dates)’ tag, and since the most common report is a trend report, Nextanalytics for Excel will automatically pivot the dates across the columns for you.

To figure out what codes you need to enter, you first have to identify the various components of the dates you have been given, and then place the corresponding codes in the correct order. For example:
1/23/10 would be represented as M/d/yy
5 JAN 10 would be d MMM yy
2010-01-23 would be yyyy-MM-dd
1997-07-16T19:20:30.45+01:00 would be yyyy-MM-dd’T'HH:mm:ss.ffzzz
| Date component | How it appears | Code to represent it |
| Year | 0 to 99 | Y |
| Year | 00 to 99 | yy |
| Year | As a 4-digit number | yyyy |
| Month | 0 to 12 | M |
| Month | 00 to 12 | MM |
| Month | Abbreviated name (Jan, Feb, Mar, etc) | MMM |
| Month | Full name (January, February, etc) | MMMM |
| Day | 1 to 31 | d |
| Day | 01 to31 | dd |
| Day | Abbreviated day of the week (Mon, Tue, etc) | ddd |
| Day | Full name of day of week (Monday, Tuesday, etc) | dddd |
| Hour | 1 to 12 (12 hour clock) | H |
| Hour | 01 to 12 (12 hour clock) | hh |
| Hour | 0 to 23 (24 hour clock) | H |
| Hour | 00 to 23 (24 hour clock) | HH |
| Minute | 0 to 59 | m |
| Minutes | 00 to 59 | mm |
| Seconds | 0 to 59 | S |
| Seconds | 00 to 59 | ss |
| AM/PM designator | Single character | t |
| AM/PM designator | Two characters | tt |
| Fractions of a second | Always showing | f to fffffff (match number of digits) |
| Fractions of a second | Show only if non-zero | F to FFFFFFF (match maximum number of digits) |
| Offset from UTC | Hours with no leading zero | z |
| Offset from UTC | Hours with leading zero | zz |
| Offset from UTC | Hours and minutes | zzz |
| Date separator | / | |
| Time separator | : | |
| Other text | Surround with single or double quotes | ‘ or “ |
Reference: http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx
date formats, Excel, trend