Free guide
Floor plan symbols and abbreviations, drawn and explained.
The 51 symbols you meet on US architectural floor plans and blueprints, each drawn the way it shows up on the sheet with one line on how to read it, plus 148drawing abbreviations in a list you can search. Built from the United States National CAD Standard, the VA’s published standard details and other public references. Free to read and print here, or download a copy to keep.
By Camila BruggerFounder and CEO
How to read the symbols on a floor plan
A plan is a cut
A floor plan is a horizontal section: the building cut above the floor and seen from above. What the cut passes through, like walls, is drawn heaviest. What sits below it is drawn lighter, and what sits above it, like soffits, beams or upper cabinets, is dashed.
Scale, or a fixed size
Doors, windows, stairs and fixtures are drawn at their real size, so you can measure them. Markers and tags are not: the NCS draws a section marker as a 16 mm (5/8 in) circle and window or wall type tags at 6 mm (1/4 in) on the printed sheet, whatever the scale.
The legend in the set wins
Symbols vary from office to office, so every set defines its own in a legend, and the NCS asks for the abbreviations a set uses to be listed on its general sheets. When a drawing disagrees with this page, the legend in that set is the one that counts.
The floor plan is one sheet type among many in a set. For where it fits next to elevations, sections and details, see our guide to the types of architectural drawings and their purposes.
Floor plan symbols, drawn and explained
Grouped the way you read a plan: lines first, then openings, stairs, fixtures, power and lighting, and the markers and tags that tie the plan to the rest of the set. Each card names the sources its drawing follows.
Walls and lines
8 symbolsLine weight and line type carry meaning: what is new, what stays, what comes out, and what sits above the cut.
New wall
A wall built as part of this project.
How to read it: The heaviest lines on the plan, often filled solid or hatched with the material from the legend.
Drawn per VA
Existing wall to remain
A wall that is already there and stays.
How to read it: Two lighter continuous lines left unfilled, so the new work stands out against it.
Drawn per VA
Existing wall to be demolished
A wall that comes out as part of the work.
How to read it: A dashed outline: on a demolition plan, what is drawn dashed is removed.
Drawn per VA
Centerline
The center of a wall, column, opening or fixture, used to locate it.
How to read it: A thin chain of long and short dashes, tagged with a C and an L drawn over each other, or CL.
Drawn per VA
Fire rated partition
A wall with a fire resistance rating.
How to read it: Count the diamonds in each group, one per hour: this one is 2 hours. An S after them adds a smoke barrier.
Drawn per VA
Property line
The legal boundary of the lot.
How to read it: One long dash and two short dashes, repeated. Often noted PL.
Drawn per VA
Break line
The point where the drawing stops short of the real object.
How to read it: A thin line with one sharp zigzag: the element keeps going, it just is not drawn.
Drawn per NCS, VA
Doors
7 symbolsDoors are drawn open so you can see how they move. An arc means the door swings; parallel panels and arrows mean it slides.
Single swing door
One hinged leaf in an opening.
How to read it: The leaf is drawn open 90 degrees at the hinge jamb, and the arc shows the side it swings into.
Drawn per NCS, VA, U.S. Navy, U.S. Army, Cedreo
Double door
A pair of leaves hinged at opposite jambs.
How to read it: Two leaves and two arcs that meet at the center, like the letter M on the swing side.
Drawn per NCS, U.S. Navy, U.S. Army, Cedreo
Double acting door
One leaf that swings both ways.
How to read it: A solid leaf and arc on one side of the wall, mirrored in dashes on the other.
Drawn per NCS, U.S. Army
Sliding (bypass) door
Two panels that slide past each other on parallel tracks.
How to read it: No arc: two overlapping panels in the opening, with arrows for the way each one slides.
Drawn per NCS, U.S. Army, Cedreo
Pocket door
A door that slides into a cavity inside the wall.
How to read it: The leaf runs along the middle of the wall into a hollow drawn inside it. No arc.
Drawn per NCS, Cedreo
Bifold door
Panels hinged together that fold as the door opens.
How to read it: Each pair of panels is an inverted V standing on the swing side of the opening.
Drawn per NCS, Cedreo
Surface sliding (barn style) door
One panel that hangs on the face of the wall and slides across the opening.
How to read it: A thin panel just outside the wall face, with an arrow pointing the way it slides.
Drawn per NCS
Windows
4 symbolsA window sits in a break in the wall. The lines inside the break tell you how the sash moves.
Fixed window
Glass that does not open.
How to read it: The wall breaks, jamb lines close its ends, and a thin glass line runs through the middle.
Drawn per NCS, Cedreo
Single or double hung window
Sashes that slide up and down.
How to read it: Two full width sash lines side by side in the wall. The vertical motion cannot show in plan.
Drawn per NCS, U.S. Navy, U.S. Army
Horizontal sliding window
Sashes that slide sideways past each other.
How to read it: Two sashes, each a little over half the width, offset and overlapping at the center.
Drawn per U.S. Army, Cedreo
Casement window
A sash hinged at one side that swings open like a door.
How to read it: The open sash and its arc show the hinge side and the side it swings to. NCS draws them dashed.
Drawn per NCS, U.S. Navy, U.S. Army, Cedreo
Stairs
2 symbolsThe arrow always starts on the floor you are looking at and points the way the flight goes, up or down.
Stair going up
A flight that rises from the floor shown.
How to read it: Tread lines, an arrow marked UP from the bottom step, and a break line where the flight passes the cut.
Drawn per NCS, U.S. Navy, U.S. Army, Cedreo
Stair going down
A flight that goes down from the floor shown.
How to read it: The arrow starts at the floor edge and points down the flight, marked DN, often with the riser count.
Drawn per NCS, U.S. Army
Plumbing fixtures
6 symbolsFixtures are drawn at their real size, against the wall they are mounted on.
Water closet (toilet)
A tank type toilet.
How to read it: A narrow tank against the wall and an oval bowl pointing into the room.
Drawn per NCS, U.S. Army, Cedreo
Wall hung lavatory
A bathroom sink mounted on the wall.
How to read it: A rectangle against the wall with a rounded basin drawn inside it.
Drawn per NCS, U.S. Army
Countertop lavatory
A bathroom sink set into a counter.
How to read it: The front and back edges of the counter as two lines, with the basin drawn between them.
Drawn per NCS
Bathtub
A tub, drawn at its real size.
How to read it: An outer rectangle, a rounded inner outline, and a small circle at the drain end.
Drawn per NCS, U.S. Army, Cedreo
Shower stall
A shower enclosure with its own base.
How to read it: A double square with an X from corner to corner. A small circle can mark the drain.
Drawn per NCS, U.S. Army, Cedreo
Double bowl kitchen sink
A two compartment sink set in the counter.
How to read it: One rectangle with two rounded bowls side by side.
Drawn per NCS, Cedreo
Kitchen appliances
3 symbolsAppliances are drawn as their footprint, most of them with a short label inside.
Range (cooktop)
A range or cooktop.
How to read it: A square with four burner circles, two by two.
Drawn per NCS, Cedreo
Refrigerator
A refrigerator, drawn at its footprint.
How to read it: A square or rectangle at appliance size marked REF.
Drawn per NCS, Cedreo
Dishwasher
A dishwasher.
How to read it: A square marked DW.
Drawn per NCS, U.S. Army, Cedreo
Electrical
8 symbolsReceptacles and switches sit at the wall they serve. Light fixtures go on the reflected ceiling plan (RCP).
Duplex receptacle
A standard two outlet receptacle.
How to read it: A small circle at the wall with two parallel lines through it that run to the wall.
Drawn per NCS, VA
GFCI duplex receptacle
A duplex receptacle with ground fault circuit interrupter protection.
How to read it: The duplex symbol plus a line across the circle, so it shows a crosshair.
Drawn per NCS, VA
Single receptacle
One outlet.
How to read it: A circle with one line through its center, running to the wall.
Drawn per NCS, VA
Quadruplex receptacle
Four outlets at one spot.
How to read it: Two lines to the wall and two across them, like a # over the circle.
Drawn per NCS, VA
Single pole switch
A switch that controls a light from one place.
How to read it: An S with a vertical stroke through it, placed at the wall near the door it serves.
Drawn per NCS, VA, U.S. Army
Three way switch
One of two switches that control the same light.
How to read it: The switch symbol with a 3. Other subscripts mark 4 way, dimmer (D) or weatherproof (WP).
Drawn per NCS, VA, U.S. Army
Recessed downlight
A round light fixture set into the ceiling.
How to read it: A small circle with the fixture type letter and four short ticks around it.
Drawn per VA
Recessed troffer (2 by 4)
A rectangular light fixture set into the ceiling grid.
How to read it: A rectangle at fixture size with one diagonal. Without the diagonal, it is surface mounted.
Drawn per VA
Reference markers
7 symbolsMarkers tie the plan to the rest of the set: each bubble names a drawing and the sheet it is on. They are drawn at a fixed printed size, not to scale (the NCS section marker is a 16 mm, or 5/8 in, circle).
Building section marker
Where a section is cut and which way it looks.
How to read it: Section number on top, the sheet it is drawn on below. The black triangle points the way you look.
Drawn per NCS, VA
Exterior elevation marker
Points to the face of the building shown in an elevation.
How to read it: Drawing number over sheet number, with the triangle aimed at the face being drawn.
Drawn per NCS, VA
Interior elevation marker
Calls out the elevations of the walls of a room.
How to read it: Each black corner aims at one wall and carries the letter of that elevation.
Drawn per NCS, VA
Detail callout
An area drawn again at a larger scale.
How to read it: The dashed outline marks the area. The bubble gives the detail number over the sheet it is on.
Drawn per NCS, VA
Column grid
The reference lines that locate columns and walls.
How to read it: Numbers run one way and letters the other, so B/2 is where grid lines B and 2 cross.
Drawn per NCS, VA
Level datum marker
A point with a known height.
How to read it: A quartered circle with two opposite quarters filled, and the elevation written beside it.
Drawn per VA
North arrow
Which way the plan faces.
How to read it: The heavy half of the vertical line points north, lettered NORTH above the circle.
Drawn per NCS, VA, Cedreo
Tags and dimensions
6 symbolsA tag sends you from the plan to a schedule or a list, where the full information lives. The NCS draws window and wall type tags at 6 mm (1/4 in).
Door tag
The door's number in the door schedule.
How to read it: A number in or next to the opening, often in a small ellipse, that you look up in the door schedule.
Drawn per NCS, VA
Window type tag
The window's type in the window schedule.
How to read it: A small diamond with the type number or letter inside, placed next to the window.
Drawn per NCS
Wall type tag
The wall assembly, keyed to the wall types.
How to read it: A small square with the type code, on the wall or tied to it with a short leader.
Drawn per NCS, VA
Room name and number
Names and numbers each room.
How to read it: The room name on one line and the room number in a small box below it.
Drawn per NCS, VA
Keynote
A numbered note that points to an item.
How to read it: A stretched hexagon with a number and a leader. The number keys to the keynote list on the sheet.
Drawn per NCS, VA
Dimension line
A measured distance.
How to read it: Extension lines mark the ends, and a 45 degree tick (or an arrowhead) marks where each one meets the dimension line.
Drawn per NCS, VA
Architectural abbreviations on floor plans
148 abbreviations you will see in plans, schedules and notes, from A to Z. Each one appears with the same meaning in at least 2 of the sources listed at the foot of this page, and 146 of them in three or more. Some abbreviations mean more than one thing: the gray line under the meaning says so, and the context on the sheet decides.
Showing 148 of 148 abbreviations
| Abbreviation | Meaning |
|---|---|
| @ | At (precedes a spacing value, e.g. studs @ 16")NPS drawing standards: when the @ symbol is used with a spacing, O.C. is normally unnecessary. |
| ACT | Acoustical ceiling tile |
| AD | Area drainAlso used for access door. |
| ADJ | Adjacent; adjustableNCS lists adjacent, adjoining and adjustable. |
| AFF | Above finished floor |
| ALT | Alternate |
| ALUM | Aluminum |
| APPROX | Approximate |
| ARCH | Architect; architectural |
| BLDG | Building |
| BM | BeamAlso benchmark. |
| BOT | Bottom |
| BRG | Bearing |
| CIP | Cast in place (concrete) |
| CJ | Control joint; construction joint |
| CL | CenterlineOften drawn as the combined C/L glyph (℄). |
| CLG | Ceiling |
| CLR | Clear; clearance |
| CMU | Concrete masonry unit |
| CO | CleanoutAlso cased opening and certificate of occupancy. |
| COL | Column |
| CONC | Concrete |
| CONT | Continuous; continue |
| CORR | Corridor |
| CPT | Carpet |
| CT | Ceramic tile |
| CTR | Center |
| DBL | Double |
| DEMO | Demolition; demolish |
| DET | DetailDTL is a common variant. |
| DF | Drinking fountain |
| DIA | Diameter |
| DIM | Dimension |
| DN | Down (stair or ramp direction) |
| DR | DoorAlso drain; context decides. |
| DW | Dishwasher |
| DWG | Drawing |
| EA | Each |
| EJ | Expansion joint |
| EL | Elevation (height above a datum) |
| ELEC | Electric; electrical |
| ELEV | ElevatorSome offices use ELEV for elevation; NCS and VA reserve it for elevator and use EL for elevation. |
| EQ | Equal |
| EW | Each way |
| EXIST | Existing |
| EXP | Expansion; exposed |
| EXT | Exterior |
| FD | Floor drain |
| FE | Fire extinguisher |
| FEC | Fire extinguisher cabinet |
| FF | Finish faceSome offices use FF for finish floor; NCS lists finish face and far face. |
| FIN | Finish |
| FIXT | Fixture |
| FLR | Floor |
| FOC | Face of concrete |
| FOF | Face of finish |
| FOS | Face of stud; face of slab |
| FTG | Footing |
| FURN | Furniture; furnish |
| GA | Gage (gauge) |
| GALV | Galvanized |
| GB | Grab bar |
| GC | General contractor |
| GL | Glass |
| GWB | Gypsum wallboardWidely used, but NCS lists "gypsum wallboard" and "drywall" among terms it does not prefer and uses gypsum board (GYP BD) instead. |
| GYP BD | Gypsum board |
| HB | Hose bibb |
| HC | Hollow core (door) |
| HDR | Header |
| HDW | Hardware |
| HM | Hollow metal |
| HORIZ | Horizontal |
| HT | Height |
| HVAC | Heating, ventilating, and air conditioning |
| INSUL | Insulation |
| INT | Interior |
| KIT | Kitchen |
| LAM | Laminate |
| LAV | Lavatory |
| LF | Linear feet |
| LVR | Louver |
| MAX | Maximum |
| MECH | Mechanical |
| MFR | Manufacturer |
| MIN | Minimum |
| MISC | Miscellaneous |
| MO | Masonry opening |
| MTL | Metal |
| N | North |
| NIC | Not in contractNCS also lists NIC for noise isolation class. |
| NO | Number |
| NOM | Nominal |
| NTS | Not to scale |
| OC | On center |
| OPNG | Opening |
| OPP | Opposite |
| PL | Property lineAlso plate (structural). |
| PLAM | Plastic laminate |
| PLBG | Plumbing |
| PLYWD | Plywood |
| PNL | Panel |
| PR | Pair |
| PT | Paint; pressure treated |
| PTN | Partition |
| QT | Quarry tile |
| R | Riser; radius |
| RB | Resilient base; rubber base |
| RCP | Reflected ceiling plan |
| REF | Reference; refrigerator |
| REINF | Reinforce; reinforced |
| REQD | Required |
| REV | Revision |
| RM | Room |
| RO | Rough opening |
| SC | Solid core (door) |
| SCHED | Schedule |
| SECT | Section |
| SF | Square foot (feet) |
| SGD | Sliding glass door |
| SHT | Sheet |
| SIM | Similar |
| SPEC | Specification |
| SQ | Square |
| STC | Sound transmission class |
| STD | Standard |
| STRUCT | Structural |
| SUSP | Suspended |
| T | Tread |
| T&G | Tongue and groove |
| THK | Thick; thickness |
| TO | Top of (followed by the element) |
| TOS | Top of steel; top of slab |
| TOW | Top of wall |
| TYP | Typical |
| UNO | Unless noted otherwise |
| UON | Unless otherwise noted |
| UR | Urinal |
| VCT | Vinyl composition tile |
| VERT | Vertical |
| VIF | Verify in field |
| W/ | With |
| W/O | Without |
| WC | Water closet (toilet)Also wall covering. |
| WD | Wood |
| WDW | Window |
| WH | Water heaterAlso wall hung and wall hydrant. |
| WP | WaterproofingAlso weatherproof. |
| WSCT | Wainscot |
Where these conventions come from
The United States National CAD Standard (NCS) is published by the National Institute of Building Sciences, which presents it as a common language for building design and documentation. Its Uniform Drawing System covers drafting conventions, terms and abbreviations, and symbols, and it files each symbol under a MasterFormat number and division title. If those numbers are new to you, here is the full list of CSI MasterFormat divisions.
The U.S. Department of Veterans Affairs publishes its standard details free of charge, including sheets of architectural and electrical symbols and 23 sheets of architectural abbreviations. Older U.S. Army and Navy print reading manuals show the same door, window and fixture conventions, and they were used here to cross check the drawings.
Where the sources differ, a drawing follows one of them and its text allows for the other. A casement window, for example, is dashed in the NCS and drawn solid in the older manuals, and the VA puts the door number in a small ellipse where the NCS writes it next to the door.
Clean drawing sets take a team that knows the conventions.
WorldTeams builds remote teams for US architecture, engineering and construction firms: vetted drafters and BIM specialists who work in your standards, your templates and your hours. If CAD production is piling up faster than your team can take it on, that is the conversation we have.
Questions, answered
What do the symbols on a floor plan mean?
Floor plan symbols are shorthand for what the building contains. Heavy filled lines are walls cut by the plan, arcs are swinging doors, thin lines inside a wall break are windows, and parallel lines with an arrow are stairs. Fixtures and appliances are drawn at their real footprint, while bubbles and tags point to other drawings and schedules. Every drawing set defines its own symbols in a legend, so check that first.
How do you read a door swing on a floor plan?
The door is drawn open at 90 degrees. The straight line or thin rectangle is the leaf, standing at the hinge jamb, and the quarter circle arc traces the path of its free edge to the strike jamb. The side of the wall where the leaf and arc sit is the side the door swings into. Two leaves with arcs meeting in the middle are a pair of doors.
What does a dashed line mean on a floor plan?
A dashed line shows something you cannot see from the cut of the plan. Short dashes usually mark hidden features, and longer dashes with wider gaps mark things above the cut, such as soffits, beams or upper cabinets. On a demolition plan, a dashed outline marks work to be removed. A chain of long and short dashes is a centerline or a column grid line.
What do AFF, TYP, NIC and VIF mean on architectural drawings?
AFF is above finished floor, the reference for heights such as a switch at 48 in AFF. TYP means typical: the note or dimension applies to every similar condition. NIC is not in contract: the item is shown, but it is not part of the work. VIF is verify in field: check that dimension on site before building. The searchable list on this page covers 148 abbreviations.
Is there a standard for architectural symbols in the US?
Yes. The United States National CAD Standard, published by the National Institute of Building Sciences, includes a Uniform Drawing System with modules for drafting conventions, terms and abbreviations, and symbols. Adoption is voluntary, so firms adapt it, and federal agencies such as the VA publish their own standard symbol sheets. Whatever a firm uses, the legend in each drawing set is the final word.
How are windows shown on a floor plan?
A window is a break in the wall with its ends closed by jamb lines and thin lines running through the gap. One glass line in the middle is a fixed window, two full width sash lines are a single or double hung window, and two offset sashes that overlap in the middle slide sideways. A casement shows its open sash and an arc, like a small door. A diamond tag next to it gives the window type.
Sources: United States National CAD Standard, National Institute of Building Sciences (NIBS); NCS Uniform Drawing System, Module 5: Terms and Abbreviations (NIBS excerpt); U.S. Department of Veterans Affairs, Standard Details: Architectural Abbreviations; VA Standard Detail, Architectural Symbols: line types; VA Standard Detail, Architectural Symbols: markers and door identifier; VA Standard Detail, Architectural Symbols: grid, tags and north arrow; VA Standard Detail, Electrical Symbols: Power Plan; VA Standard Detail, Electrical Symbols: Lighting Plan; U.S. Navy NAVEDTRA 14040A, Blueprint Reading and Sketching; U.S. Army TM 5-704, Construction Print Reading in the Field; National Park Service, Electronic Drawing Standards; Wikipedia, Engineering drawing abbreviations and symbols; Archtoolbox, Architectural Abbreviations; Group Architect, Architecture Abbreviations; 3DAS, Architectural Abbreviations; The House Plan Shop, Construction Drawing Abbreviations; Cedreo, Floor Plan Symbols and Abbreviations.
Last updated September 23, 2026.