Need help breaking down UA e-receipt
 

I plan to only submit part of my ticket cost for an upcoming expense report. I've figured out the segment airfare costs on the e-ticket but the following line doesn't quite add up for me and I'd appreciate any assistance people could render.

Taxes and fees add up to $76.10 total per United. No Hawaii or Alaska travel.

XT 20.40ZP 10.00AY 18.00XFBOS4.5LAX4.5SAN4.5DEN4.5

So 20.40ZP must be my excise tax of $3.40 per segment as I have 6 segments on this itinerary. 10.00AY is the 9/11 fee for 4 departure points on this trip. 18.00XF is the PFC for each of the 4 airports involved.

That adds up to $48.40 which leave $27.70 unaccounted. What am I missing here? What taxes have I not added in so far?

Per United they list:
Travel within Domestic 50 United States:
Airport passenger facility charges (PFCs) of up to US $18 roundtrip
U.S. government excise tax of US$3.40 on each flight segment†
September 11th Security Fee of US$2.50 per enplanement at a U.S. airport
For travel to or from Hawaii and Alaska: U.S. government excise tax of $7.50 per direction
† A flight segment is defined as each sector of an itinerary that involves one takeoff and one landing

Is your fare by any chance $277? Tax on airfare is 10%.

You seem to have got all the ones that you listed. Here are the IATA codes. You can try going using ITA to build your itinerary. It should give you the detailed fare breakdown with taxes.

ZP = Flight Segment Tax (Domestic)
AY = Passenger Civil Aviation Security Service Fee
XF = Passenger Facility Charge

I thought the Transportation Tax was 7.5% Did it go up?

Thanks for the help so far. The airfare on the ticket was $369.30.

You're right. I don't know why I always thought it was 10%. And 7.5% of $369.30 is $27.70, so case closed.

Thanks everyone. This'll help quite a bit!

It was 10% at one time, then reduced to the current rate (I think in two stages).