Whether you're a homebuyer estimating square footage, an architect checking measurements, or a real estate agent preparing a listing, this free online tool lets you calculate room areas and total floor area directly from a floor plan image — no expensive software required.
Click "Upload Floor Plan" or drag and drop any JPG or PNG image of your floor plan.
Click "Auto-Detect" to find wall intersections automatically, or use Draw Room to manually trace each room.
Draw a reference line over a known dimension (e.g. a 90 cm door) and enter the real-world length to calibrate the scale.
Instant area, perimeter and bounding-box dimensions for every room, plus total floor area in m² or ft².
Adding vertices: In Draw Room mode, click to place each vertex. Click the first vertex again (or press Enter) to close the polygon. You can also double-click any edge to insert a new vertex mid-line.
Editing: Switch to Select mode to drag any vertex to a new position. Right-click a vertex to remove it. Right-click a room to rename or delete it.
Snapping: When Auto-Detect has run, corners glow green. Your cursor snaps to them while drawing for precise alignment.
Zoom & Pan: Use the scroll wheel to zoom and Alt+drag (or middle-mouse drag) to pan around a large floor plan.
The calculator works in pixel coordinates until you provide a real-world reference. Using the Reference Line tool, click two points on a feature whose real dimension you know — such as a standard internal door (usually 80–90 cm wide) or an exterior wall shown on the architect's legend. Enter that real dimension in the dialog box, and all areas and lengths will instantly convert to real-world units.