About the Polygonal Lasso Tool
The polygonal lasso selects with straight lines. Tap or click the first corner, then the next, and so on around the object. When you have gone all the way round, press Close shape. It is the best tool for things with straight edges, such as buildings, signs, screens, books and furniture, and it gives cleaner edges than a freehand trace. Then keep the selection and make everything else transparent, or remove it and leave a hole. Add a soft edge, crop to the selection and save a PNG with real transparency. Nothing is uploaded.
Updated October 2026
How to use the Polygonal Lasso Tool
- 1Select an image or drop one on the page.
- 2Tap or click corner after corner around the object. Pink dots show your corners.
- 3Use Undo last corner if you misplace one.
- 4Press Close shape, then choose Keep or Remove the selection and a soft edge.
- 5Press Cut out the selection and Download PNG.
Straight edges, clean cuts
Many objects in photos are made of straight edges: a building, a window, a poster, a laptop screen, a table top. A freehand lasso wobbles on such edges, while a polygon follows them exactly. By placing corners at the corners of the object, you get a selection as precise as the corner positions.
Placing corners
Start at one corner of the object and move around it in one direction. Place a corner wherever the edge changes direction. For gentle curves add corners every few pixels. On a phone, zoom your browser in before you start if the object is small, since each tap places one corner.
- Straight edges: one corner at each end
- Curved edges: many corners close together
- Misplaced corner: Undo last corner
- Done: Close shape
What to do with the selection
Keep the selection to get the object on a transparent background. Remove it to cut a hole in the picture, for example to put a new sky behind a building. A soft edge of a few pixels hides tiny irregularities. Crop to the selection removes the empty area around the object.
A quick example
To cut a painting out of a photo of a wall, tap its four corners and press Close shape. Choose Keep the selection and Crop. The result is a picture of the painting alone on a transparent background, with the wall gone.
Phone and computer
On a phone, tap with one finger; the page does not scroll while you touch the picture, so scroll with the area around it. On a computer, click with the mouse. Pictures up to about 16 million pixels work.
Good to know
A polygon needs at least three corners. The path is not allowed to be empty, and crossing lines are filled by the even-odd rule, which leaves holes where the path overlaps itself. If you see an odd hole, clear and redraw without crossing. For curved selections use the Lasso Tool, and for flat colour areas the Magic Wand Tool is faster.
Features
- Straight-edged selection with corner dots
- Undo the last corner
- Keep or remove the selection
- Soft edge and crop to selection
- Transparent PNG output
- Private: runs in your browser
Frequently asked questions
When is the polygonal lasso better than the freehand lasso?
For objects with straight edges. Clicking corners gives crisp lines that a shaky hand cannot draw.
How do I finish the shape?
Press Close shape. The last corner is joined to the first by a straight line, and the selection is made.
Can I fix a misplaced corner?
Press Undo last corner to remove the most recent one and click again. You can also press Clear selection to start over.
Can I select a curved object?
Place many corners close together along the curve, which approximates it. For a smooth curve use the Lasso Tool or the Ellipse Select Tool.
How do I keep a transparent background?
Download as PNG, which keeps transparency.
Is my picture uploaded?
No. Everything is done in your browser.