How to Draw Doors and Windows in Floor Plans (Step by Step)

How to Draw Doors and Windows in Floor Plans

To draw a door on a floor plan, break the wall at the door’s width and close the two wall ends with short jamb lines. Draw the door leaf as a thin line or narrow rectangle standing at 90 degrees from the hinge, then sweep a quarter-circle arc from the tip of the leaf back to the closed position. The arc’s radius equals the leaf width. To draw a window, break the wall in the same way, then run three thin parallel lines across the gap: two for the frame faces and one in the middle for the glass. Finally, tag both with marks like D1 and W1 that point to a schedule giving the height, material and sill level, because a floor plan cannot show height by itself.

That is the drawing. The harder part is choosing where each opening goes and which way each door swings, because a perfect symbol in the wrong place is still a mistake.

Picture a bedroom that is 3.6 m by 3.6 m. The door is drawn neatly, the arc is a clean quarter circle, and the plan gets approved. Then the bed arrives and the door stops 20 cm short of opening fully. Nothing on the drawing was “wrong”. The swing was drawn, but nobody tested it against the furniture. On a small plot, where every square metre was paid for with real money, that kind of slip is expensive.

So I will show you the symbols first, then the part most tutorials skip. You will get a swing-area formula that shows how much floor a door really uses, a three-line test for whether a window is big enough, a coursing trick that saves your mason from cutting blocks, and a 12-point check to run before any plan leaves your table. You will also get a short exercise at the end so you can test yourself. Stay for the numbers, because they are what separate a plan that looks right from one that works.

First, what a floor plan is actually showing you

Before drawing anything, it helps to know what a floor plan is. Imagine slicing the whole building horizontally with a giant knife, roughly 1.2 m to 1.5 m (about 4 to 5 ft) above the floor, then lifting off the top half and looking down. Whatever the knife cuts is drawn with heavy lines. Whatever sits below the cut is drawn lighter.

That one idea explains three things people usually memorise without understanding:

• Walls are thick, heavy lines because the knife went through them.
• Windows appear in the wall because a normal window (sill at 900 mm, head at 2100 mm) is cut by the knife.
• High-level windows are often drawn dashed. A bathroom window with its sill at 1500 mm sits above the knife, so by convention it is shown as something you cannot see on the cut, which is a dashed line. Many offices draw it solid and write “HL” beside it. Either is fine as long as you are consistent.

It also explains why a floor plan cannot give a window’s height. The plan only shows width and position, and the height lives in the schedule and the elevation. Keep that in mind, because it comes back in the schedule section.

Set your scale and line weights before you touch a door

The size a door takes up on paper depends entirely on your scale. The formula is simple:

Drawn length = Real length ÷ Scale number

At 1:100 a 40 mm thick door leaf is 0.4 mm on paper, which is thinner than most pencil lines. That is why leaves are drawn as a single line or a very narrow rectangle at that scale. Use 1:50 for plans you want a mason to build from, and 1:100 when the whole house must fit on one sheet.

Line weight matters just as much, because it tells the reader what was cut and what was not. These are common office conventions, not a law:

If your walls and your swing arcs are the same weight, the plan looks flat and the eye cannot find the doors. Heavy walls with light arcs is the quickest fix.

If you are drawing walls from my wall guide, draw the whole wall first as unbroken lines, then cut the openings out of it. Cutting openings while you draw walls leads to gaps that are not quite the size you meant.

Drawing a door, step by step

Take a bedroom door as the example: a 900 mm leaf in a 150 mm internal wall.

Mark the opening. Measure along the wall from the nearest corner and mark where the door starts and stops. For a 900 mm leaf, the structural opening is a little wider than the leaf to allow for the frame, so mark the opening as the number your schedule gives (commonly 950 to 1000 mm).

Break the wall. Erase or trim the two wall lines between your marks.

Close the wall ends. Draw a short line across the wall thickness at each end of the opening. These are the jambs. This is the most common beginner error: leaving wall ends open makes the wall look like it keeps going through the door.

Pick the hinge side. Decide which end the hinge sits on. Draw the leaf from that end, standing out at 90 degrees from the wall, as a thin rectangle about 40 mm thick at your scale or a single line at 1:100.

Sweep the arc. Put a compass point on the hinge, open it to the leaf width, and draw a quarter circle from the tip of the open leaf to the closed position inside the opening. In CAD this is the ARC command with the hinge as centre.

Add the tag. Write D2 in a small circle or oval near the door, outside the swing, so the label does not sit on the arc.

The symbol for every door type

Typical door sizes

The leaf width is not the clear width you can walk through. A rule of thumb is clear width ≈ leaf width − about 90 mm, because the leaf, hinges and stops eat into the opening. A 900 mm leaf gives roughly 810 mm clear, which is why accessibility codes (the US figure is commonly cited as 815 mm, the UK varies with approach direction) point you toward a 900 mm leaf for any door a wheelchair must use. Check your own country’s code for the exact number.

The swing: where small plots win or lose

Now the part that costs people money. A swing door does not just open, it claims a quarter circle of floor that nothing else can occupy.

Swing area = π × r² ÷ 4, where r is the leaf width in metres.

Now apply it to a small-plot three-bedroom house. Three bedroom doors at 900 mm give 3 × 0.64 = 1.91 m². Two bathroom doors at 750 mm give 2 × 0.44 = 0.88 m². That is about 2.8 m² of floor you built, plastered, tiled and painted, and cannot put a bed or a toilet on.

Look at the bathrooms in particular. A 1.5 m by 2.0 m bathroom is 3.0 m², and one 750 mm door swinging inward takes 0.44 ÷ 3.0 = 14.7% of the room. Make that door swing outward into a corridor that is 1.2 m or wider, or recess it into a small alcove, and the bathroom gets that area back. For a real figure in your own currency, take the cost per square metre from your quantity surveyor and multiply by 2.8.

Rules I use for every swing

Hinge next to the nearest wall, so the door opens flat against it and reveals the room as you walk in rather than hiding behind it.

Never let two doors hit each other. Doors on facing walls should be offset, and doors in a corner should open away from each other.

Keep arcs clear of beds, wardrobes and toilets. Draw the furniture in at real size before you decide the swing.

Keep the corridor passable. If a leaf opens into a corridor, the corridor must still be walkable while it is open. A 0.9 m leaf in a 1.0 m corridor leaves 0.1 m. That is a trap.

Public or crowded buildings usually need doors swinging outward in the direction of escape. Houses commonly swing inward. Check your local code.

A note on “left-hand” and “right-hand” doors: the convention changes between countries and even between offices. If you write LH or RH on a plan, the carpenter might read it opposite to how you meant it. The arc and the hinge position are unambiguous, so rely on them and add a note like “hinge this side” when in doubt.

Draw the swing of every door, even the ones that “obviously” swing one way. A mason or carpenter will read the arc literally, and the cheapest time to change a swing is on paper.

Drawing a window, step by step

1. Mark the opening along the wall, the same way as for a door.
2. Break the wall between the two marks and draw jamb lines at each end.
3. Draw the frame faces. Draw two thin lines across the gap, one flush with each wall face.
4. Draw the glass line. Add a third thin line down the middle, which is the glass. Some offices draw the sill as an extra line projecting beyond the outside face, so check what your drawing standard says.
5. Show the opening type. Add a small indicator for how it opens (see the table).
6. Tag it W1, W2 and so on, and note the sill height if it is not standard.

In elevation drawings, a casement’s opening direction is shown by dashed lines that meet at the hinge side. In plan it is usually shown by the arc or by nothing at all, so say which one your office uses.

Sill height and head height

A normal living-room or bedroom window has its sill at about 900 mm, so you can see out while seated and so furniture can sit under it. The head (top of the window) is commonly at 2100 mm, level with the door head. That alignment is not decoration. It lets one lintel run over both a door and a window beside it, which is simpler and cheaper to build.

Head height = sill height + window height. A window with a 900 mm sill and a 1200 mm height has a 2100 mm head. A bathroom window with a 1500 mm sill and a 600 mm height has the same head at 2100 mm, so the lintel line stays level across the whole wall.

Is the window big enough? The three-line test

Every habitable room needs light and air from the outside. Rules differ by country, but the US residential code gives a clear reference point. It requires glazed openings of at least 8 percent of the room’s floor area for natural light, and openable portions of at least 4 percent of floor area for natural ventilation, with fixed glass counting only toward the light requirement. jaspector

Use that as a sanity check, even if you build elsewhere, and then confirm your own authority’s number:

1. Light needed = floor area × 8%
2. Air needed = floor area × 4%
3. Openable area = window area × openable fraction

Worked example, a 3.6 m × 3.6 m bedroom:

• Floor area = 12.96 m²
• Light needed = 12.96 × 0.08 = 1.04 m²
• Air needed = 12.96 × 0.04 = 0.52 m²

Try a two-sash sliding window of 1.2 m × 1.2 m: area 1.44 m², which is 11.1% of the floor, so light passes. Only one sash opens, so openable area = 1.44 × 0.5 = 0.72 m², which is 5.6%, so air passes too.

Now shrink it to 0.9 m × 1.2 m because the plot is tight. Area 1.08 m² gives 8.3%, which just passes. Openable 0.54 m² gives 4.2%, which just passes. That is the point where small-plot designers get caught. A sliding window fails the air test long before it fails the light test.

My own working target in a hot, humid climate is closer to 10 to 15% of the floor area for the main rooms. That is design judgement, not a code requirement. In our weather, airflow is comfort, and a house that depends on a fan during a power cut needs more opening, not less.

For a bathroom of 3.0 m², 8% is 0.24 m², so a 0.6 m × 0.6 m high-level louvre at 0.36 m² passes comfortably.

Putting openings where the structure allows

A floor plan has to agree with the structure, or the mason will fix it on site in whatever way is quickest.

Between columns, not through them

In a reinforced-concrete frame with sandcrete infill, openings must sit between columns and beams. A window that drifts onto a column line, or a door drawn through the middle of a column, will either force a redesign or get built wrong. Overlay your column grid on the plan before you place a single opening.

Lintel length

Every opening needs a lintel above it, and the lintel rests on the wall at both ends.

Lintel length = opening width + 2 × bearing

With a 1200 mm opening and a 225 mm bearing each side: 1200 + 2 × 225 = 1650 mm. The bearing length is for your structural engineer to confirm. It also means you cannot place an opening closer to a corner than the bearing allows, so keep at least that much solid wall beside it.

The beam-soffit gap

In a two-storey house, suppose the floor-to-floor height is 3.0 m and the beam above is 450 mm deep. The underside of the beam sits at 3.0 − 0.45 = 2.55 m. A door that is 2.1 m high leaves 2.55 − 2.1 = 0.45 m above it. You can fill that with block, make the door taller, or use it as a fixed or louvred fanlight so hot air can leave at the top of the room. That last option is cheap airflow and I use it often. (These numbers are an example; your engineer’s beam sizes govern.)

A coursing trick that saves cutting blocks

Standard Nigerian blocks are about 450 mm long and 225 mm high, including the joint. If your opening width and height are multiples of those, the mason lays whole blocks and does not cut them. For example, a window with a 900 mm sill (4 courses), a 2250 mm head (10 courses) and a height of 1350 mm (6 courses) fits the coursing exactly. Choose a width of 1350 mm (3 blocks) instead of 1200 mm (2⅔ blocks) and you avoid a cut on every window. Aluminium windows are made to measure so they do not mind, but the blockwork around them does. Confirm the actual block size and joint thickness with your mason before you lock the schedule.

Small-plot problems, and how the drawing solves them

Windows close to the boundary

On a small plot the side setback is often tight. Many authorities restrict or ban openings in walls very close to a boundary for fire, privacy and noise reasons. The exact distance varies, so look up your own state’s or country’s rule. Where it is tight, keep side windows small and high, or take light from the front and rear and treat the side wall as solid.

Privacy between neighbours

Two windows looking straight into each other across a 3 m gap will never feel private. Offset them, raise the sill to 1500 mm, or use obscure glass. Draw the neighbour’s likely window position on your plan if you can.

Cross-ventilation

Draw an arrow from the main window through the room to an opening on another wall. If you cannot draw a clean line of air, the room will feel stuffy however large the window is. Openings on two different walls, or a high-level opening opposite a low one, move air much better than two windows side by side on the same wall.

Sun on east and west faces

Morning and afternoon sun hit east and west walls at a low angle and heat the room. Shade those windows with an overhang or a louvre, or keep them smaller. This should show on your plan as a roof overhang line, not only in the elevation.

Burglar-proof bars

In Nigeria, most windows get bars. If the bars are fixed to the outside of the frame, a casement window opening outward cannot open at all. Either specify windows that open inward, or use sliding or louvre types. Mark “BP” on the plan and tell the window maker before fabrication, because bars bolted on afterwards often block the opening you drew.

Doors that fight the furniture

Before you finalise a swing, draw the bed, wardrobe and bedside tables in at real size. A bed is typically 1.5 m × 2.0 m (double) or 1.8 m × 2.0 m (king), and a wardrobe is about 0.6 m deep. If the arc touches any of them, move the hinge to the other side or flip the swing before you approve the plan.

Tags and schedules: the part that makes your drawing buildable

A plan with unmarked openings is a sketch. A plan with tags and schedules is a document someone can price, order and build from.

Each opening gets a mark (D1, D2, W1, W2) in a small circle or oval beside it. The marks point to two tables:

Door schedule (example)

Window schedule (example)

Two checks stop most schedule errors. First, the quantity in the schedule must equal the count of that tag on the plan. Second, the sill and height in the schedule must match what the elevations show. If the plan says 1350 and the elevation says 1200, the contractor will build whichever he reads first.

Doing it in CAD

If you draw in AutoCAD, set up before you draw:

• Put doors on a layer called A-DOOR and windows on A-GLAZ. These follow the common US layer naming convention, and any name works as long as it is consistent.
• Draw one door as a block with the hinge as the insertion point and the width as a parameter. A dynamic block lets you stretch it to 750, 900 or 1000 without redrawing the arc.
• Use TRIM or BREAK to open the wall, then insert the block. Draw jambs on the wall layer.
• Attach the tag to the block as an attribute so the schedule can be pulled out automatically.

In parametric tools like Revit or ArchiCAD, the symbol is generated for you, but the swing direction, the sill height and the hinge side still need to be checked by you. The software does not know your bed is there.

A 12-point check before the plan leaves your table

1. Every opening has jamb lines closing the wall ends.
2. Every arc has a radius equal to its leaf width.
3. No swing hits a bed, wardrobe, toilet or another door.
4. Every corridor stays at least 900 mm to 1000 mm wide with a door open.
5. Every opening sits between columns, with enough solid wall beside it for the lintel bearing.
6. Door and window heads line up at one level (or at the beam soffit).
7. Every habitable room passes the light and air test, using your local percentage.
8. Every main room has openings on two walls, and east and west windows are shaded.
9. Windows near a boundary follow your authority’s rule for openings.
10. Window opening direction does not clash with burglar-proof bars.
11. Every opening has a tag, and the schedule quantity matches the plan.
12. The plan, elevations and schedule give the same sizes and sill heights.

Print the plan and walk it with a coloured pencil, tracing the path from the front gate to every room. Each place the pencil stops because of a door or a clash, you have found a mistake that would have cost you on site.

Mistakes I would stop making

• Leaving the wall open at a door or window.
• Drawing the arc with a radius that is not the leaf width.
• Drawing a window across a column line.
• Putting a door directly opposite the toilet.
• Using the same line weight for walls and arcs, so nothing stands out.
• Forgetting that a floor plan gives width but not height.
• Copying a door block from another drawing without checking its size.

How this changes in other countries

The symbols are almost identical worldwide, because the plan-cut logic is the same. What differs is units, standard sizes and the rules behind the numbers.

Whatever the country, the logic is the same: draw the symbol, size it to the room, and check it against your own code.

Try it yourself (3 minutes)

A bedroom is 3.0 m × 3.5 m inside. It has a 900 mm leaf and a sliding window of 0.9 m × 1.35 m.

1. What is the floor area, and how much glazing and openable area does the 8% / 4% test need?
2. What is the window’s glazed area and openable area?
3. How much floor does the door swing take?

Answers: Floor area = 10.5 m². Needed: 0.84 m² glazing and 0.42 m² openable. The window is 1.215 m² glazed (11.6%) and 0.61 m² openable (5.8%), so it passes both. The door swing is π × 0.9² ÷ 4 = 0.64 m², or about 6% of the room.

Where to go from here

If you are drawing a plan for a small plot, the symbols are the easy part. The decisions that save you money are the swing, the sill, the column line and the room’s air. Draw them on paper first, where changing your mind costs a pencil stroke, and not on a half-built wall, where it costs a lintel and a repaint.

If you want ready-made small-plot plans that already have the doors, windows and schedules worked out, browse our Plans Library. To learn how to read and draw plans from scratch, visit Plan School. If you would rather have a professional draw and check yours, our Services page explains how we work. You can also find more guides on our Homepage.

FAQ

What is the symbol for a door on a floor plan?
A gap in the wall with a thin leaf standing at 90 degrees and a quarter-circle arc showing the swing.

How do you show a window on a floor plan?
Three thin parallel lines across a gap in the wall, with a tag and a schedule giving size and sill height.

How wide is a standard door on a floor plan?
About 900 mm for bedrooms, 750 mm for bathrooms and 1000 to 1200 mm for a main entrance, though sizes vary by country.

How do you show which way a door swings?
The arc shows the swing, and the hinge is at the end where the arc meets the wall.

How do you draw a sliding door?
Two parallel offset lines in the wall thickness with an arrow or note; no arc.

How big should a window be?
A common reference is at least 8% of the floor area in glass and 4% openable, then adjust to your local code.

Do I need a door and window schedule?
Yes. A floor plan shows width and position, and the schedule gives height, material and quantity.

Should doors open inward or outward?
In houses, usually inward, except where a swing would hit furniture or where local code requires outward for escape.

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Author

Massodih Okon is a Nigerian built-environment professional with academic and professional experience in urban and regional planning, geography, architectural design, Landscape Design, GIS and land development.

He holds a Master’s degree in Urban and Regional Planning from the University of Uyo and a first degree in Geography and Regional Planning.

Through MassodihPlans, he publishes practical guides on Nigerian house plans, building design, physical planning, site planning, development approval and residential construction. Read the full author profile →

About The Author

Massodih Okon

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