Guide
Straightening documents, whiteboards and buildings shot at an angle
Photos taken at an angle turn rectangles into trapezoids: a document photographed on a desk, a whiteboard shot from the side of the room, a painting in a museum, a building front from the street. Perspective correction maps the four corners of that shape back to a true rectangle, producing a flat, front-on image. This tool does it with four draggable corners.
Placing the corners
After adding a photo, four handles appear. Drag each one onto a corner of the object you want to straighten: the corners of a page, the edges of a screen, the frame of a painting, the corners of a facade. They stay in order, top left, top right, bottom right, bottom left, so the result is never flipped. Zoom into the photo on a phone or use a large window on a computer for precise placement.
The shape of the result
The output rectangle needs a shape. Auto estimates it from the distances between your corners, a good choice for most photos taken from near the front. For paper, choose A4 or Letter so the document has its true proportions even when shot at a steep angle. Card uses the size of bank and ID cards, 85.6 × 54 millimeters. Square, 4:3 and 16:9 suit artworks, screens and slides.
Document clean-up
“Clean up as a document” turns the straightened result into a clean, high-contrast grayscale image with white paper, removing shadows and the yellow cast of indoor light. It makes receipts, letters and forms easier to read, print and send. Leave it off for photos, artworks and colored documents.
Getting a sharp result
The far side of an angled photo has fewer pixels, which must be stretched. The straighter and closer the original photo, the sharper the result. Use good light, hold the phone parallel to the page when possible, and keep the whole object in the frame with a small margin around it.
Typical uses
Digitizing receipts for expenses, saving notes from a whiteboard after a meeting, straightening photographed book pages and printed forms, capturing slides from a conference, documenting paintings and posters, and correcting converging lines on building fronts for real-estate and architecture photos.
Formats
JPG keeps files small for photos and color documents. PNG preserves sharp text perfectly, ideal for cleaned-up documents. The result’s pixel size is shown before downloading.
From photo to PDF
After straightening several pages, combine them into one document with JPG to PDF, or use Scan to PDF, which works with your camera directly. For searchable text, run Image to Text OCR on the cleaned result.
Privacy
Receipts, IDs and letters stay on your device; nothing is uploaded.
Building fronts and keystoning
When you tilt a camera up at a building, vertical lines lean inward, an effect called keystoning. Place the corners on the building’s outline, choose Auto or a suitable ratio, and the verticals become parallel again. Leave some space around the building in the original photo, because the correction crops the edges.
Related tools
For simple rectangular cropping, use Crop Image. To straighten a slightly tilted horizon without perspective change, Rotate Image is quicker.
Checked against the current version of the Perspective Crop on .