Airplane seat numbering: what seat 12A means
Updated
Seat 12A is a row number and a seat letter. The conventions behind them are simple, but they have enough exceptions that a seat map has to get them exactly right.
Row number plus seat letter
An aircraft seat number has two parts. The number is the row, counted from the front of the aircraft towards the tail. The letter is the position across the cabin. So 12A means row 12, seat A.
On most aircraft, letters run from left to right as you face the front of the aircraft, so A is commonly the left window seat. The last letter in the row is then the right window seat, and the letters either side of an aisle are aisle seats.
None of this is a single worldwide rule. It is common practice, and each airline sets its own numbering for each aircraft type. A seat map has to follow the airline's numbering, not a generic pattern.
Rows counted from the front
The first row behind the cockpit is commonly row 1, and numbers rise towards the tail. In a two-cabin aircraft, the front cabin might use rows 1 to 5 and economy might continue from 6, or it might start again at a higher number such as 10 or 20. Airlines that jump like this often do it so the same row numbers mean roughly the same place across all their aircraft of one type, even when the front cabin has a different number of rows.
Gaps in the numbering are normal. Many airlines leave out row 13, and some leave out other numbers that are considered unlucky in the markets they serve. A cabin reconfiguration can also leave gaps when the airline keeps the old numbers for the rows that did not move. The result is that the highest row number is rarely the number of rows. A seat map must never be built by counting rows and numbering them 1 to n.
Seat letters across the cabin
Letters follow the seat positions, and when a cabin has fewer seats per row than the one behind it, some letters are commonly skipped so that window and aisle letters stay the same through the aircraft. Typical patterns look like this, but always check the real aircraft:
| Layout | A common lettering | Where you see it |
|---|---|---|
| 3-3 | A B C | D E F | Economy on single-aisle aircraft |
| 2-2 | A C | D F | Business or first on single-aisle aircraft |
| 3-4-3 | A B C | D E F G | H J K | Economy on twin-aisle aircraft |
| 2-4-2 | A C | D E F G | H K | Premium cabins on twin-aisle aircraft |
In the 2-2 example, B and E are left out so that A and F stay window letters and C and D stay aisle letters, exactly as they are in the 3-3 cabin behind. In wide cabins the letter I is commonly skipped because it is easy to confuse with the number 1, which is why the right window is often K rather than J. Some airlines skip other letters too. Copy the lettering from the airline's own seat plan or from the aircraft documentation, row by row.
Cabins and classes
Each cabin is a separate product: first, business, premium economy, economy. On a seat map each cabin should be its own section with a name and a fare category, so a booking system can price and filter by cabin. Cabins can share a numbering sequence or restart it, but the section name always tells the passenger which cabin a row belongs to.
Inside a cabin, some rows are sold differently. Bulkhead rows behind a cabin divider often have more legroom but no seat in front for storage. Rows with extra pitch may be sold as a separate seat category. Give these seats their own category or a flag on the map, rather than writing a note on a picture. The booking system can only act on what is stored as data.
Exit rows
Exit rows sit beside the emergency exits: at the doors and, on many single-aisle aircraft, over the wing. They often have extra legroom and are commonly sold at a premium. They also come with conditions. Airlines usually restrict who may sit in an exit row, for example passengers who are able and willing to help in an evacuation, and not passengers travelling with an infant. The exact conditions come from the airline and its aviation authority, so check the operator's current policy.
On the seat map, mark the exits on both sides of the cabin and mark the exit row seats so the booking system can apply its own checks before it sells them. The rows directly in front of an exit row may have limited recline, which is useful to show as well.
Galleys, lavatories and what else to draw
Passengers choose seats by what is around them. Some want to be near a lavatory, many want to be far from one. Seats beside a galley can be noisy and busy during service. Draw these areas where they really are:
- Galleys at the front, rear and sometimes in the middle of the cabin.
- Lavatories, including the larger accessible one where the aircraft has it.
- Emergency exits on both sides, at each door and over-wing exit.
- Cabin dividers and bulkheads, so it is clear which row is the first of a cabin.
- Seats that are not for sale, such as seats held for crew or blocked by the operator.
A worked example
Take a single-aisle aircraft with a small business cabin and a long economy cabin. Business has five rows of four seats in a 2-2 layout, lettered A, C, D and F. Economy starts at row 10, has a 3-3 layout lettered A to F, and runs to row 38 without a row 13. There is an over-wing exit row with extra legroom in the middle of economy, galleys and lavatories front and rear.
Economy runs from row 10 to row 38, which looks like 29 rows, but without row 13 it is 28. That small difference is exactly the kind of thing a seat map should get right once and never be retyped by hand. Seat 12A is the left window seat in the third row of economy. Seat 3D is the right aisle seat in the third row of business. Every label on the boarding pass matches a single seat on the map.
What a seat map for booking needs
A seat map that a booking or check-in system can use needs more than the picture. For every seat it needs:
- A stable id that does not change when the map is edited.
- The cabin (section) the seat belongs to, with its fare category.
- The row number and seat letter, and the combined label such as 12A, exactly as printed on the boarding pass.
- The seat category or flags: exit row, extra legroom, accessible, restricted.
- A status the booking system can change: free, reserved, sold, blocked.
The general data model is covered in what a seat map needs for online booking, and putting it on a web page is covered in how to build an interactive seat map for a website. For coaches and rail carriages, which follow different habits, see bus and train seat layouts.
Checklist before you publish an aircraft seat map
- Rows are numbered from the front, with the airline's real gaps (no row 13 if the airline skips it).
- Letters match the airline's plan in every cabin, including skipped letters.
- A is on the side the airline uses for A, and window and aisle letters are where passengers expect them.
- Every cabin is its own section with a name and a category.
- Exits are drawn on both sides and exit row seats are marked.
- Galleys and lavatories are where they really are.
- Seats that are not for sale are marked as such.
- Every label on the map matches the label the boarding pass will print.
How seatorio helps
The Transport theme in seatorio starts from a ready body outline of an airplane (or a train or a bus), drawn with the front at the top. Rows are numbered with numbers and seats with letters out of the box, so seats read 12A, 12B, 12C, and seats are drawn square like on an airline seat map. Each cabin is a section with its own name and category. You can rename a single row, which is how you leave out row 13 or start economy at row 10, and you can number a selected group of seats from any starting letter, which is how a business cabin reads A, C, D, F.
Emergency exit, galley, WC and no smoking icons can be placed anywhere on the plan. Seats can be marked as wheelchair, accessible or restricted view, set as VIP, or marked not for sale, which shows them with a cross. The airplane seat map template has a 2-2 business cabin and a 3-3 economy cabin numbered like the example above.
When the map is ready, you export it as an SVG in which every seat carries its id, a uuid, its section and a status, and as a JSON file with the row and seat labels. Your booking or check-in system does the rest: seatorio does not sell seats, store passengers or run check-in. See seatorio for transport for the full theme.
Planning for transport? See seatorio for transport and the airplane seat map template.