My husband and I will be traveling beginning of Sept. from SFO to IAD (Dulles) on United. We have frequent flier miles and wanted to use them to upgrade from economy to first class. How is the best way to do this to ensure we get first class seating?

I will try to provide some general feedback on upgrading on United Airlines:

United, along with most other airlines, separate their available seats into three “buckets”:

  • Seats that you can buy with money
  • Seats that are available for redemption using miles
  • Seats that are available for upgrade from a lower class

There are only a limited number of seats available on any flight, and the airlines constantly try to adjust their pricing as well as availability in the various buckets to maximize their return. This mechanism is very fluid, and takes into account factors such as traffic load, competitor’s fare promotions, weather conditions, economic factors, proximity to the date of flight, number of seats already sold, fares that the seats were sold for, and many other factors. The results is that there is no simple way to predict with 100% certainty the buckets that would be available at any given time.

Many airlines make it very difficult to find out the inventory available in the various buckets, however, United provides its customers a tool called “Expert mode” to check for upgrade inventory.

To set your user status to expert mode in MileagePlus, complete the following steps:
1. Log into
2. Go to your Mileage Summary page
3. On the left hand side, under your name and account balance, click the link “My profile”
4. Click “Edit” in the first section on the left “My travel preferences”
5. On the fourth section “Display preferences”, the first field is “Availability format”, select “an expert”. Save the change

Now, whenever you want to see the upgrade inventory of a flight:
1. Go to the “Planning and Booking” menu at the top, do not click, but look for “Booking with Miles”
2. Select the radio button at the top “Standard award”
3. Enter the origination and destination you want, and the date, leave the Service class as Economy.

When the available flights show up, move the mouse cursor to “>Flight info”, and keep the cursor there
A pop-up will come up, displaying the route, equipment, and most importantly, the Availability.
The format will be something like this: F5, P0, A0, Y8, B8, E7, M8, U4, H1, Q0, V0, W0, T0, S0, K1, L0, NF0, XF0, NC0, XC0, G0, NY0, XY0.

The first part of the list shows the revenue seat availability, starting with the most expensive class (F), to the least expensive (L).
- F, P, and A are all First class seats, F is full fare, A is discounted F
- Y, B, E, M, U, H, Q, V, W, T, S, K, and L should be all Economy class

Here is the key to deciphering the rest:
NF – Upgrade to First class
XF – Award First class seats, using miles
NC – Upgrade to Business class
XC – Award Business class seats, using miles
G – not sure
NY – Award Economy seats, using miles, extra inventory reserved for 1K.
XY – Award Economy seats, using mles

The number behind each of the classes is the inventory available for each. Maximum of 9. For upgrades to First, you want to look for NF.

The best use of the above technique is BEFORE you purchase your ticket. If you have flexibility in the dates and time of your travel, then by searching for the flight with NF availability, you could then book those flights, and know that you will be able to immediately confirm your upgrade without having to be placed on a waitlist (where you may or MAY not ever be upgrades into First). Of course, before you actually purchase the ticket, you should call United to confirm that there is indeed NF availability before the purchase.

10 Responses

  1. Followed above directions, updated profile to expert, tried booking a flight to OGG, put cursor on flight info as instructed, and no coding appeared to show availability of any seats.

  2. G is a non-upgradeable deep discount economy fare class.

  3. Richard Thompson

    I am trying to use this information for a flight next year to Maui from Philadelphia. I followed your steps and I can see the availability now, but there are only single letter codes for all of the various fare classes I do not see any double letter codes that match up with the above information. There is no XF,NF,NC, NG etc. Have they changed the designations?

  4. We ran some searches on flights from Philadelphia to Maui in March of 2011 and the two letter codes displayed as expected. Perhaps the site was malfunctioning at the time you tried to search (members of don’t call the site “.bomb” for nothing).

  5. I was so happy when I found this info, because it is like pulling teeth to get someone at United on the phone to check multiple dates for upgrade availability. But United has changed their website and I’m not sure if there is something different that need to be done to see the NF,NC, etc codes. I only see the one letter codes. Based on the instructions above – the radio button “Standard Upgrade” is no longer there. Under “Book flight” there is a “Advanced Search” button. On this screen there is a “I would like to use this upgrade” option. I tried different combinations with different destinations to no avail. I do not see the NF, NC, etc codes, only the one letter ones. Has anyone been able to get the upgrade info with the new United site? Thanks!

  6. The site is still working this way with some minor changes:

    Expert mode is now set under: My Profile -> My travel information -> Display preferences is the fourth section.

    Make sure you set this selection to “An Expert”, otherwise, none of this will work.

    Now that you have set the Expert mode, do the following:

    1. You could either use the pull-down menu, under “Planning and Booking”, and select “Book with miles”, OR on the home page, just select the tab on the left “REDEEM MILES”

    2. Either way, make sure that you select the radio button “Standard Award” so that you can see the inventory easily.

    3. A simple test to see if you are doing it right is to try to book LAX-SFO using miles on a STANDARD AWARD.

    4. It will cost you 50,000 miles, but don’t worry, we are not actually going to book the flight, just to demonstrate the steps.

    5. There will be 10 – 15 flights each day between LAX and SFO listed, move your cursor to the “Flight details” in BLUE, just below and to the right of the link to “View seats”.

    6. Do not click the “Flight details”, just leave the cursor on top of it for a second or two, and a pop-up will be displayed showing the available buckets are described above.

    7. If this is still not working, double check that you have set EXPERT MODE, and that you are using STANDARD AWARDS.

  7. I am also only getting one letter booking fares, although I am set up as “An Expert” in my profile.
    I just booked a RT (2 flight per way) and was upgraded on one flight with a SWU, without “NC” being listed on that flight under “Flight info”.

  8. I tried through the “Standard Award” method, described above, and I was able to get the 2 letters booking codes. On the flight where I was able to get an upgrade, there was still an available upgradable seat (NC1). Thanks.

  9. On my Mac with Safari Internet browser, you need to click “flight details” to see the inventories on a pop-up window.

  10. This information is great. I’m searching for a flight to Hong Kong and am trying to find a flight where I might be able to upgrade to business class. I do have a question though, when searching for flights with the “Advanced” search, what is the difference in resulting flights between the options in the “I would like to use this upgrade” versus purchasing a flight selecting “No upgrade” and then “requesting” an upgrade after the purchase?

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