This schematic of a United Airlines 777 is typical of what you will see at Seatguru.com

When you finally book your airplane ticket for your trip, you likely will be asked to choose a seat.

The initial choices are easy–aisle or window–but after that, it can get murkier.

The average jumbo jet used for international travel has somewhere between 250 and 400 seats in a variety of classes. Add to that the fact that some airlines are now asking for additional money for a particular seat–again aisle or window–and your choice becomes all the more critical.

Now factor in that you will be in that seat for up to 12 hours. Maybe seated next to a stranger. The days of jumping to an empty row after the doors close is as quaint as a telephone booth. Not many around any more.

What else goes into figuring out your best seat options? Does the seat recline? How many seats in the row? Is it too near or too far from a restroom? Does it have an outlet to charge your phone or run your laptop?

This can vary not only from airplane model to airplane model, but by airline. It can become daunting, yet it is a critical part of travel.

To assist you this is one of the handiest website in travel–Seatguru.com.

This handy reference has seating charts for almost every airline and breaks them out by model. It then not only rates the seats for attributes good and bad, but gives measurements.

The most important number is “seat pitch.” That is the distance between the back of your seat (where your back is touching) and the back of the seat ahead of you (where the tray table is). In economy it varies from 29 to 32 inches depending on the plane and airline.

If you want to know how tight that is, sit in a dining room chair and hold a yardstick parallel to the floor. Now look where 30 inches is. Tight!

When you go to Seatguru.com, find your airline and the type of plane you will be flying upon. That information is on most airline websites or a site such as Kayak.com.

Use the information on Seatguru as a guide to trying to get the best seat possible for you.

The one warning is that airlines can and do change scheduled equipment (airliner models) on routes without warning. That could invalidate all your hard work. But it is better to be comfortable than sorry.