Class descriptions/Upgrade availability
 

After several failed searches, I am forced to ask a questions that has undoubtably been discussed before...so don't get too upset.

Does anyone have a KLM specific booking class abbreviation definition list?

and

Can anyone tell me if there is an online booking tool that will show that available number of seats in each class for upgrade purposes?

thanx!

There are booking tools like itn.net and others like amadeus which will show exact availability in each booking class (also depends on the booking tool). In many cases, when you set it to "expert mode" you get something like the following:
Departs AMS 6:55 Arrives CDG 8:15
Cabin class: J9 C9 Z9 S9 B9 M9 K9 H9 L9 Q9 T9 V9

On intra-European flights, the JCZ classes are for Europe Select, on intercontinental this is Business Class.

For the economy cabin basically the highest fare is S, all the way down to V-class.

These classes vary per airline.

No booking tool shows the award classes although I've seen a post on this site that Northwest (KL partner) has a site that shows the chances of award upgrades being available or not, also for KLM flights (?).

A wide open business class cabin does not necessarily mean an upgrade can be booked, this is dependent on the number of seats they allocate for upgrade tickets (apparently on some flights none what so ever).

Oh yes, don't forget that upgrades can be booked in the lounges too just prior to departure but of course depending on number of seats available. To the US destinations this is only available on S and B class. I heard this will be expanded to rest of destinations next year. So enjoy while you can...