Guides
Drawing a floor plan to scale
To scale does not mean measuring every line as you draw. It means the drawing exists internally in real metres and the scale only appears at output. Work that way and the same plan prints at 1:50, 1:100 and 1:200 without redrawing anything.
The habit that breaks this is drawing by eye and correcting individual dimensions afterwards. The plan is then right in three places and wrong everywhere else — and the area calculation is worthless even though the labelling looks correct.
Calibrate first, then draw
Start from a known length. Measure an external wall or a long internal wall and enter that dimension first. Every other wall follows from it, and each room's area then falls out of the geometry automatically.
After that, work by typing numbers rather than by eye. A wall whose length you entered is correct; a wall that looks about right is an error you will never find again.
- Start from one measured reference length
- Type wall lengths instead of estimating them
- Snap right angles where reality is square
- Check two dimensions against the building when finished
Which scale you need
For flats and houses, 1:100 is the standard: a typical dwelling fits an A4 sheet and room names stay legible. 1:50 suits single rooms and detailed fit-out drawings; 1:200 suits large buildings and floors with many units.
Choose the scale to fit the sheet, not the other way round. A 1:50 plan squeezed onto A4 is unusable even though the ratio is formally correct.
Keeping the scale through export
The critical moment is printing. As soon as somebody selects "fit to page" or copies an A3 plan onto A4, the printed 1:100 is wrong. The scale bar stays correct, because it scales with the drawing.
So always put a scale bar on the plan alongside the ratio. For recipients who genuinely need to measure, supply a DXF anyway — there the geometry sits in millimetres and is independent of any paper size.
Frequently asked questions
Which scale is usual for residential plans?
1:100. A typical dwelling fits an A4 sheet and the labelling stays readable. 1:50 is for detail drawings, 1:200 for large buildings or whole floors.
How do I check whether my plan is to scale?
Measure two distances on site that lie far apart on the plan and compare. If both deviate by the same proportion, the calibration is off; if only one does, there is an input error at that point.
Does the scale survive in a PDF?
The drawing does; the print only if nothing is rescaled. That is why a scale bar belongs on every plan — it scales with the page and stays correct after a format change.