How to read a floor plan: symbols and dimensions
Last updated: 26 October 2026
A floor plan is a horizontal cut through one storey, about one metre above the floor, seen from above. Cut walls appear as thick lines, doors with a quarter circle for the path of the door leaf, windows as thin lines inside the wall opening, and stairs with a walking line that starts with a circle at the bottom step and ends with an arrow pointing up. The figures on the dimension chains are usually structural (unfinished) dimensions, and the scale is given in the title block.
What a floor plan shows
Imagine cutting the house horizontally at about one metre and looking down into it. Everything the cut passes through, such as walls, columns and window frames, is drawn with heavy lines. Things that lie lower and are only seen, such as floor edges, stair treads or furniture, are drawn thinner. Parts above the cutting plane, for example an opening in the ceiling, are often dashed.
Every plan has a title block with project, storey, scale, date and author. Many also have a legend of the symbols and abbreviations used, and a north arrow. The legend always wins: not every office draws the same way.
The main symbols
Walls
Exterior walls and load-bearing interior walls are usually drawn thicker and are often hatched or filled. Thin lines show lightweight partitions, for example plasterboard. The wall thickness appears as a figure on the dimension chain, such as 36.5 for an exterior wall or 11.5 for an interior wall, both in centimetres.
Doors
You recognise a hinged door by a line for the door leaf and a quarter circle, the swing arc. It shows which room the door opens into and how much space the leaf needs. Where the line of the leaf meets the wall is where the hinges are, the hinge side.
In Germany, whether a door is "DIN left" or "DIN right" is set by DIN 107: you stand on the side the door opens towards and look at the hinges. If they are on the left, it is a DIN-left door; on the right, a DIN-right door. Double doors have two arcs, sliding doors a line parallel to the wall.
Next to the door you often find the size of the structural opening, width and height. For a standard German interior door to DIN 18101 that is 88.5 × 200.5 cm. The door leaf is narrower, and the clear passage narrower still.
Windows
Windows sit as an opening in the wall with two or three thin lines for frame and glass, often with a line for the sill on the inside. Next to them are the width and height of the opening and the sill height (German: BRH, Brüstungshöhe), meaning how high the bottom of the opening is above the finished floor.
Stairs
The walking line shows which way the stair rises: it starts with a circle or dot at the first step and ends with an arrow at the last. Because the plan is cut at about one metre, the drawn stair ends at a diagonal break line. The part above is often dashed. You will frequently see a note like "16 Stg. 17.2/28.6": 16 risers (German: Steigungen), each 17.2 cm high, with a 28.6 cm going.
Reading dimension chains
Around the outside of the plan there are usually several dimension chains side by side. The chain closest to the building measures openings and wall sections; the outermost gives the overall length. In between you often find projections, recesses or grid dimensions. Inside the plan you find the room dimensions between walls and the wall thicknesses.
- Dimensions under one metre are usually in centimetres (24), larger ones in metres (3.76). German plans use a decimal comma: 3,76.
- A superscript figure means millimetres: 3.76⁵ means 3.765 m, 88⁵ means 88.5 cm.
- Level marks with a small triangle give heights, usually relative to ±0.00 = top of the finished floor on the ground floor.
Never measure a copy with a ruler. Copies and PDFs are often reduced or distorted. The written figures are what counts.
Scale
The scale tells you how much the plan is reduced. In Germany, building permit drawings are usually at 1:100, construction drawings at 1:50, details at 1:20 or larger.
| Scale | 1 cm on the plan equals | typical for |
|---|---|---|
| 1:500 | 5 m | site plan |
| 1:200 | 2 m | overviews |
| 1:100 | 1 m | building permit, sales brochure |
| 1:50 | 50 cm | construction drawings |
| 1:20 | 20 cm | details |
Orientation
The north arrow shows where north is. It tells you which rooms get sun: in Germany the sun is in the south at midday, rises in the east and sets in the west. A living room with windows facing south or west is bright in the afternoon and evening; a bedroom facing east gets morning sun.
Structural and finished dimensions
Unless the plan says otherwise, the figures are usually structural dimensions, measured on the bare, unplastered wall. Plaster, tiles or wall linings make the finished room smaller. An example: a room is 4.01 m wide in the shell. With 1.5 cm of plaster on each side, 3.98 m remain.
Heights, on the other hand, usually refer to the finished floor (German: OKFF). The bare structural floor (OKRF) lies lower by the screed, insulation and floor covering. For furniture and fitted kitchens, the finished dimension is what matters, so measure the finished room before you buy.
Abbreviations on German floor plans
| Abbreviation | Meaning |
|---|---|
| BRH | sill height, from finished floor to top of the structural sill |
| RH | room height, usually from finished floor to underside of the structural slab |
| LH, i. L. | clear height ("im Lichten") |
| OKFF | top of finished floor |
| OKRF | top of structural floor |
| UKRD, OKRD | underside, top of structural slab |
| lichte Weite | clear width between two building parts, such as the reveals of an opening |
| Stg. | risers of a stair |
| GOK | ground level |
| NN, NHN | height above German sea-level datum |
| WD, DD | opening in a wall, opening in a slab |
| FBH | underfloor heating |
| KG, EG, OG, DG | basement, ground floor, upper floor, attic storey |
| WZ, SZ, KI, HWR, AR | living room, bedroom, children's room, utility room, storage room |
Meanings can vary slightly between offices. When in doubt, the plan's legend applies.
Tracing a floor plan in RoomPlanning
If you have a floor plan as a photo, scan or PDF, put it under your plan in RoomPlanning as a reference image. Set its scale with two points of known distance and trace the walls over it (Drawings and export). You type wall lengths directly, and with the reference line you can draw along the inside face if you measured inside (Drawing walls). For doors you set the hinge side and opening direction, just as in the plan (Doors and windows).
Then every room shows its area, and the 3D view tells you whether you read the plan correctly. Try it straight away in the editor or start from one of the template floor plans.
Frequently asked questions
How can I tell which way a door opens?
From the quarter circle: it lies in the room the door swings into. The straight line is the open door leaf, and the hinges are at its wall end.
What does the small superscript figure on a dimension mean?
It stands for millimetres. 2.01⁵ means 2.015 m, 11⁵ means 11.5 cm.
Are the dimensions on the plan the real room sizes?
Usually not quite. Plans normally show structural dimensions. The finished room is smaller by the plaster and linings. For furniture it is best to measure yourself.
What does a scale of 1:100 mean?
One centimetre on the plan equals 100 cm, or one metre, in reality. A room 4 cm long on the plan is 4 m long.
Sources
- Grundrisse entschlüsseln: Ein Leitfaden – sanier.de (German)
- Lauflinie (walking line) – Baunetz Wissen (German)
- DIN-links und DIN-rechts – Baunetz Wissen (German)
- Wandöffnungen und Türgrößen nach DIN 18101 – Baunetz Wissen (German)
- DIN 18065: Gebäudetreppen – WEKA (German)
This guide is general information and is not legal or planning advice.