Keystone Correction Tool

Keystone distortion happens when the camera is tilted up or down at a building or room. Vertical lines that are parallel in reality converge in the photo, so the subject looks wider at one end than the other, like the keystone shape of an arch. It is most noticeable in architecture, interiors and real estate photography with wide-angle lenses.

Click the area at the top and choose an image file. The Adjust Distortion controls appear with two sliders, Top Width and Bottom Width, both starting at 100. Adjust them to counter the convergence in your photo, then click Apply & Download. The corrected image is saved to your device as keystone-corrected.png. Check it, and if the lines still lean, change the sliders and apply again.

Each slider ranges from 50 to 150 percent of the image width, with 100 meaning no change. The tool maps the top and bottom edges of your photo to those widths, centered, with a true perspective warp in between. If verticals lean inward toward the top, as when shooting up at a building, widen the top relative to the bottom until the lines look parallel.

The output keeps your photo's original dimensions. Widening an edge beyond 100 pushes parts of the image outside the frame, so they are cut off, while narrowing an edge leaves transparent areas at the sides of the PNG. Leave some space around your subject when shooting so you have room to correct, then crop the PNG in your editor to remove any empty areas.

Keep the camera level, with the sensor parallel to the building's facade, and use a higher shooting position or a wider lens with room to crop instead of tilting up. A tilt-shift lens corrects perspective optically. When tilting is unavoidable, shoot a little wider than needed so that correction in post leaves enough image for your final crop.

Yes. It is free, adds no watermark and needs no software. Your photo is processed in your browser on your own device and never leaves it. To use the tools, you answer once that you are a photographer and create or log into a free Imagen account, which unlocks every tool on the site.