What accuracy means for floor plans
Floor plan accuracy is typically expressed as a deviation per measurement. A deviation of 1 cm per wall means the measured wall length differs from the actual wall length by up to 1 cm. For a 5-meter wall, that is an error rate of 0.2%.
Two numbers matter in practice: deviation per wall and cumulative error across a full building. A method that is accurate per individual measurement but introduces systematic errors when rooms are stitched together produces an unusable floor plan. LiDAR scanning handles both — per-wall accuracy and room-to-room consistency — because the sensor builds a continuous point cloud rather than a series of individual measurements.
LiDAR floor plan accuracy: what the data shows
Metaroom floor plans produced with iPhone Pro or iPad Pro are accurate to within 1% per wall. For a typical room with walls between 3 and 6 meters, the deviation is 1 to 2 cm per wall. Total area calculations for a 70 m² apartment are typically within 1 to 2 m² of the actual figure.
| Method | Accuracy per wall | Cumulative error (full apartment) | Redraw required? |
|---|---|---|---|
| Tape measure | ±5 to 10 mm (operator-dependent) | Errors accumulate with building size | Yes — always |
| Laser distance meter | ±1 to 2 mm per measurement | Errors accumulate with manual entry | Yes — always |
| LiDAR scan (iPhone Pro) Recommended | Within 1% (1 to 2 cm per wall) | Consistent — continuous point cloud | No — generated automatically |
| Professional laser scanner | 1 to 3 mm | Very low | No — but requires specialist equipment |
A laser distance meter measures individual distances more precisely than LiDAR. However, the floor plan produced from those measurements is only as accurate as the person entering and drawing them. Manual entry introduces its own errors — transposition mistakes, missed angles, and inaccurate sketches. LiDAR captures the full geometry in one pass without manual intervention.
Is 1 to 2 cm accuracy sufficient for professional work?
For most professional building documentation, 1 to 2 cm accuracy is sufficient. The table below shows the accuracy requirement for common use cases.
| Use case | Accuracy needed | LiDAR sufficient? |
|---|---|---|
| Renovation planning and quotes | 1 to 3 cm | Yes |
| Energy certificate documentation | 1 to 5 cm | Yes |
| As-built documentation | 1 to 3 cm | Yes |
| Electrical base plans | 2 to 5 cm | Yes |
| Lighting planning (DIALux, Relux) | 2 to 5 cm | Yes |
| CAD and BIM input files | 1 to 3 cm | Yes |
| Custom joinery and fitted furniture | 1 to 5 mm | No — use laser distance meter |
| Structural surveys | Sub-millimeter | No — use professional laser scanner |
LiDAR scanning covers the majority of professional documentation use cases. For fitted furniture dimensions or structural work, a laser distance meter or professional scanner is more appropriate.
For rooms where fitted furniture or built-in cabinets are planned, a two-step workflow delivers both speed and precision. Scan the full room with Metaroom to get the complete floor plan and room geometry in 10 to 20 minutes. Then measure the 3 to 5 critical dimensions — niche width, installation depth, distance to power outlets — with a laser distance meter. This gives you millimeter accuracy where it matters, without spending 2 to 4 hours measuring the entire room by hand.
What affects LiDAR scan accuracy?
LiDAR accuracy on iPhone Pro and iPad Pro is consistent across most conditions, but a few factors influence the result.
Slow, steady movement
Walking slowly through each room gives the sensor more time to capture geometry. Scanning each wall from multiple angles improves point cloud density.
Lighting conditions
LiDAR uses infrared laser pulses, not visible light. Scan accuracy is the same in a dark room as in a well-lit one. Lighting does not affect results.
Highly reflective surfaces
Mirrors, glass walls, and highly polished floors can scatter LiDAR pulses and introduce gaps. Scan these areas more slowly and from multiple angles.
For standard rooms with painted walls, concrete floors, and normal ceiling heights, accuracy is consistently within 1%. Unusual materials or geometries may require additional attention during scanning.
Camera-based scanning vs. LiDAR: accuracy comparison
Some apps produce floor plans on standard iPhones and Android devices using camera-based depth estimation rather than LiDAR. These apps infer distances from images rather than measuring them directly.
Camera-based floor plans are typically accurate to ±5 to 15 cm per wall under good conditions, with larger errors in low light, near plain surfaces, and in rooms with unusual geometry. For professional documentation, this level of accuracy requires manual verification and correction. LiDAR scanning eliminates the need for post-scan correction in standard rooms.
Frequently Asked Questions (FAQ)
Metaroom is a professional floor plan scanning app for architects, tradespeople, and energy consultants. You scan a room with iPhone Pro or iPad Pro — the app captures geometry automatically using LiDAR. Scan accuracy is within 1%, or about 1 to 2 cm per wall. The result is a dimensioned 2D floor plan and 3D model, exportable to PDF, DXF, IFC, or Excel in 30+ formats. A 3-room apartment scans in under 20 minutes.
