A walkthrough of every function in the tool. Four steps, a few optional tools, and a printable PDF report at the end.
Click Upload Floor Plan to select a file from your device. PlanSnapper accepts JPEG, PNG, WEBP, and PDF. PDF files are automatically rendered to an image (first page only) so you can trace them like any other floor plan.
Works best with:
After uploading, PlanSnapper asks whether your floor plan shows multiple floors on one image. Most plans are single-floor — click Skip to proceed directly to tracing.
If the plan shows a first floor and second floor side by side on a single image, use the lasso tool to select each floor separately before tracing. PlanSnapper will measure each one independently and label them in the results. See our guide to measuring multi-story homes.
Click Lasso a Floor Level to draw a selection box around one floor on the image. A modal will prompt you to name it — choose from suggestions like "Main Level", "Upper Level", or "Basement", or type your own.
Repeat for each floor. Lassoed floors appear as a checklist in the sidebar. Once all floors are identified, click Done to proceed to tracing. Each floor will be measured in isolation.
Click Auto Detect to run computer vision on the floor plan. The tool analyzes contrast edges, finds the exterior boundary, and places a polygon around it automatically.
Works reliably on clean floor plans with a clear exterior perimeter. If the polygon looks close but not perfect, you can accept it and adjust — or switch to manual trace for full control.
Controls how aggressively the auto-detect algorithm bridges gaps in the floor plan outline. A higher value connects lines across larger breaks — useful for floor plans with room labels, furniture, or hatching inside the boundary.
Start at 35 (the default). If the polygon fragments or doesn't close, increase toward 80. If it collapses to a rectangle and misses detail, decrease toward 10.
Click Manual Trace to draw your own polygon by clicking each corner of the exterior perimeter. Click to place each vertex, working your way around the boundary. The polygon closes automatically when you click near the starting point.
Use manual trace when:
Secondary actions are grouped in a compact icon row below the primary trace buttons. Hover any icon to see its label and keyboard shortcut. The icons are:
Click the straighten icon (or press O) after tracing to snap all vertices to the nearest orthogonal alignment — horizontal or vertical walls only. Useful for buildings where you know every wall is a 90° angle and want to clean up a rough manual trace in one click.
Click the add area icon (or press N) to trace a second (or third) region. Use this for:
Each polygon is calculated independently and listed in the results. The total shown is the combined square footage of all polygons.
Press R or click the remove points icon to toggle remove mode. While active, the icon highlights red and a hint bar appears below the toolbar. Click any vertex to delete it — the polygon closes cleanly around the remaining points.
Useful for cleaning up auto-detected polygons with extra vertices, and works well on touch screens where dragging small targets is harder than tapping.
When you start tracing manually, PlanSnapper runs a background scan to detect wall corners in the floor plan image — the intersections of horizontal and vertical lines. While you are placing vertices, a blue ring appears whenever your cursor is within snapping range of a detected corner.
Click anywhere near that ring and the point snaps exactly to the wall corner — no need to zoom in and pixel-hunt. The snap indicator appears and disappears automatically as you move around the canvas.
Once the perimeter looks right, click Approve Trace to lock it in and advance to the scale-setting step. You can always come back to redo the trace.
The tool calculates area in pixels. Before it can convert that to square feet (or meters), it needs one known dimension to use as the pixel-to-feet ratio. You can provide that either by identifying a wall or by picking any two points.
When you upload a dimensioned floor plan — one with room measurements printed on it like 12 x 10 or 5'6" x 8'4" — PlanSnapper scans the image in the background using OCR (optical character recognition) and extracts any dimension labels it finds.
If dimensions are detected, blue chips appear at the top of the Set Scale step. Click one and the tool enters two-point mode with the distance pre-filled — just click the two endpoints of that wall and scale is set automatically, with no typing required.
Two toggle pills control the wall offset applied to each detected dimension:
Click Choose Wall to Set Scale, then click on any wall segment in your traced polygon. The selected wall highlights. A dialog asks you to enter the real-world length of that wall in feet (or meters).
This is the fastest method when you know one wall measurement — for example, from a recorded deed, a previous inspection, or a dimension printed on the floor plan itself.
Click Pick Two Points to Set Scale, then click any two points anywhere on the image — not just on the polygon. A dialog asks you to enter the real-world distance between those two points.
Use this when you want to measure between two features that aren't walls in your polygon — like across a room, using a known dimension from the opposite side of the floor plan, or using a reference object in an aerial photo.
Click Calculate Square Footage to run the final computation. Results show:
Clears the current polygon, scale, and results so you can start over on the same image. The uploaded image stays — you don't need to re-upload.
A magnified loupe appears near your cursor whenever you are placing or adjusting vertices. It gives you a zoomed-in view of the area under your cursor so you can snap to exact corners and edges without needing to zoom the whole canvas.
The loupe is always active whenever an image is loaded and your cursor is over the canvas. You do not need to turn it on — it appears automatically any time you are working with the floor plan.
Navigate the floor plan canvas with standard mouse and trackpad gestures:
Common shortcuts for faster tracing and editing:
Once an image is loaded, the project name appears at the top of the sidebar. Click the pencil icon to rename it — a modal lets you type a property address or any label. The name appears in the PDF export header and is used to identify saved projects.
Click Save Project to store your floor plan, polygon, scale, and results to the cloud. Projects are tied to your account and accessible from any device.
To reopen a saved project, go to My Projects from the tool navigation. All measurements and the floor plan image are restored exactly as you left them.
Click Export as PDF to generate a one-page measurement report. The report includes:
The report is formatted to fit a single page. It opens in a new browser tab and triggers your system print dialog — use "Save as PDF" to export the file.