Areas, perimeters & a sketch
Room area calculator & floor plan sketch
Draw rooms on a grid, or type their sizes, and read off each room's floor area and perimeter with the total, in square metres and square feet. The plan stays in this browser and exports as SVG or PNG.
Select a room to move it, drag its corners, or edit it in the panel. Drag empty space to pan.
Rooms and areas
| Room | Area | Perimeter |
|---|---|---|
| 20 m²215.3 ft² | 18 m | |
| 13.44 m²144.7 ft² | 16 m | |
| 8 m²86.1 ft² | 13.2 m | |
| 17 m²183 ft² | 16.8 m | |
| 6 m²64.6 ft² | 9.8 m | |
| Total (5) | 64.44 m²693.6 ft² | 73.8 m |
Selected room
Choose a room on the plan or in the list above to rename, move or reshape it.
x runs right and y runs down from the plan's origin mark.
Add a room by typing
Save and export
Your plan is saved in this browser automatically. Nothing is uploaded.
How to use the floor plan sketch
Choose Rectangle and drag across the grid to draw a room, or choose Shape and click each corner in turn for an L-shaped or angled room; click the first corner again, double-click or press Enter to close it (Backspace removes the last corner, Escape cancels, Shift keeps sides straight). Corners snap to the grid and to the corners of other rooms, so neighbouring rooms meet cleanly.
With Select, drag a room to move it or drag its round handles to reshape it. The panel beside the plan renames, nudges, duplicates or deletes the selected room, and its corner list can be edited directly.
No mouse? Add a room by typing: give a width and depth, walk round the walls ("right 4, down 3, left 4"), or list the corners. Lengths can be typed as 3.45, 345 cm or 12' 6". In the plan, arrow keys move the selected room and Delete removes it.
Areas use the shoelace formula, which works for any shape whose sides do not cross; perimeters add up the sides. Draw the inside faces of the walls for floor area, as you would measure for flooring.
Worked example
The example kitchen is an L: 4 × 4 m with a 1.6 × 1.6 m corner taken out, 16 − 2.56 = 13.44 m². Its perimeter is the outline all the way round, 16 m. The five rooms of the example flat add up to 64.44 m², or 693.6 ft².
Sources
- NIST, SI units: length: the inch has been exactly 25.4 mm since 1959, so a foot is exactly 0.3048 m and 1 m² is about 10.764 ft².
Questions
How do I work out the area of an L-shaped room?
Split it into two rectangles and add their areas, or take the missing corner away from the full rectangle. Here you can draw it as one shape by clicking its six corners, or type it as directions such as "right 4, down 3, left 1.5, down 1, left 2.5".
How do I convert square metres to square feet?
Multiply by about 10.764, because a foot is exactly 0.3048 m and a square foot is 0.0929 m². A 20 m² room is about 215 ft². Every area here is shown in both units.
Should I measure inside or outside the walls?
For flooring, carpet, tiles and paint for the floor, measure inside, wall to wall. Official or sales floor areas can follow other rules (some include the walls), so use those definitions when you need a figure for a listing.
Where is my plan saved?
Only in this browser's local storage, saved after every change. To move it to another device, download the JSON backup and open it there. Clearing the plan or your browser data deletes it.
Can I use it with a keyboard only?
Yes. Add rooms with the typing form, pick a room from the list, then rename it, edit its corners or move it with the arrow buttons. When the plan has focus, arrow keys move the selected room and Delete removes it.