FloorSQ estimates the area inside the plan outline you select. It is a tool for comparing properties from floor-plan images—not a survey, valuation or official record of floor area.
What FloorSQ actually measures
FloorSQ works from a floor-plan image. It first separates the plan drawing from other page elements, such as listing headers, logos and content captured around the plan. It then identifies connected parts of the drawing that appear to belong to the property and creates an editable outer boundary.
FloorSQ measures the pixel area inside the selected outline, then converts it to square metres using the scale currently in use. A valid reference line with a known length takes priority; when no valid line is active, a room with labelled dimensions provides the fallback scale. The result is not necessarily the same as internal area, gross floor area, strata area or the area stated in a sales contract. Each measure may treat walls, balconies, stairs, garages and outdoor spaces differently.
- Input: a clear JPG, PNG or WebP floor-plan image.
- Scale reference: a valid line drawn over a known distance, or at least one readable dimension matched to the correct fallback room.
- Measured area: the non-transparent pixels inside the editable floor-plan outline.
- Output: an adjustable estimate and review warnings.
From a known distance or printed room dimension to a plan scale
In Space Planner, draw a reference line over a distance whose real length you know and enter that length in metres. FloorSQ divides the real length by the line length in pixels and assumes the image uses the same scale horizontally and vertically. Once valid, this line becomes the live scale and takes priority over the selected reference room.
Without a valid reference line, FloorSQ falls back to a labelled room. A room labelled 4.0 m × 3.0 m represents 12.0 m². If the corresponding room box is 200 pixels wide and 150 pixels high, it covers 30,000 square pixels. Dividing the known room area by its pixel area gives the area represented by each square pixel. Switching fallback rooms can be a useful cross-check, but it does not change the live scale while a valid reference line is active.
metres per pixel = known reference-line length ÷ reference-line pixel lengthreference-line area factor = metres per pixel × metres per pixelarea conversion factor = (dimension A × dimension B) ÷ (room-box pixel width × room-box pixel height)floor area estimate = outline pixel area × active area factorWhy boundary position matters
Wall lines on a floor plan have thickness. A detected boundary can fall on the inner face, centreline or outer face of a wall, and may shift between those positions where the drawing is faint. The same issue affects a reference line, the fallback reference-room box and the outline of the whole property.
FloorSQ therefore lets you reposition the reference line, move room edges and edit outline points. Use one convention consistently. If the reference line or fallback room measures between inner wall faces while the outer outline follows external faces, the result will mix two definitions and may be inaccurate.
- Use inner faces when you want an approximation of usable internal space.
- Use an outer-face or centreline convention only when it matches the figure you are comparing against.
- Check garages, patios, balconies, voids and detached structures individually rather than assuming they have been classified for you.
Known limits of image-derived measurement
Results are most reliable with clear, complete real-estate floor plans that have straight walls and readable metric dimensions. Dark backgrounds, perspective distortion, low-resolution screenshots, decorative textures, gaps in boundaries, angled walls and overlapping site plans can all reduce the accuracy of plan extraction or text recognition.
FloorSQ cannot determine a reliable scale when no trustworthy real-world distance is available for a reference line and no readable room dimension can provide a fallback. It also cannot tell which measurement standard the agent, architect or surveyor used, or which standard was used for the strata plan. A plan may omit wall thickness, show different levels at different scales, or include spaces that are not part of the advertised internal area.
- Do not use an estimate as a substitute for a survey, valuation or contractual disclosure.
- Do not rely on it for building approvals, insurance, finance or setting out renovation work.
- Ask for source documents and professional measurement when the area could affect an important decision.
A sensible review before using the result
Check that all relevant parts of the plan are included. When a valid reference line is active, verify both endpoints and the entered length, then cross-check another known distance with a measurement line where possible. Otherwise, confirm that the fallback dimension belongs to the selected room and that its box uses the same wall convention as the main outline.
The best use of FloorSQ is comparative: screening listings, checking whether an advertised figure appears plausible and preparing better questions for an agent or inspector. Independent verification remains the final step whenever accuracy matters.