Free Perspective Correction Tool
You snapped a photo of a contract, a receipt, or your notes from a whiteboard meeting. Now it's sitting on your phone — tilted, trapezoidal, and completely useless for filing or sharing.
That's the exact problem PerspectiveFix was built to fix. No drama, no detours.
PerspectiveFix is a browser-based perspective correction tool. You load a skewed image, drag four corner handles to mark the edges of your document, and the tool mathematically warps the image flat — like digitally ironing out a crumpled page.
The result looks like it came off a flatbed scanner. Straight edges, readable text, correct proportions.
It runs entirely inside your browser. There's no app to install, no account to create, and — this part matters — your files never leave your device.
The core mechanic is a homographic transformation. When you place the four corners on your image, the tool calculates a transformation matrix that maps that irregular quadrilateral to a perfect rectangle.
Under the hood, it uses the HTML5 Canvas API and Web Workers — the same browser primitives used by professional image editors. Processing happens on your CPU, locally, in real time.
Here's the step-by-step:
The whole process takes about 20 seconds once you know what you're doing.
Most "free" online tools quietly send your files to their servers. PerspectiveFix doesn't. Everything runs client-side. If you're working with tax documents, medical records, or anything sensitive — this distinction matters.
After straightening, hit the Enhance button. Two modes:
Six manual controls if you want granular control:
The ratio dropdown lets you force standard paper sizes — A4, US Letter, Square — or enter exact pixel dimensions. If you need a 2480×3508 print-ready file, type it in. The tool caps at 4096px per side and scales proportionally to stay within a 16MP budget.
Full undo and redo stack for corner adjustments. A grid overlay helps you verify alignment before downloading — useful when the document edges aren't obvious.
For power users: R resets corners, Q rotates 90°, F opens filters, E opens enhance, G toggles the grid, Ctrl+Z / Ctrl+Y for undo/redo, Ctrl+S to download.
Photographing lecture slides, whiteboards, and textbook pages is standard practice. The problem is those photos are rarely straight. PerspectiveFix gets them reading-ready in seconds — no CamScanner subscription needed.
Signed contracts, expense receipts, handwritten meeting notes — all of these regularly need to go into a PDF or an email chain. A quick straighten pass makes them look filed, not photographed.
Interior shots taken at an angle often show converging vertical lines — the "keystoning" effect. Dragging the corners to the room's actual edges corrects that without Lightroom or Photoshop.
Product packaging shots taken at an angle look unprofessional in listings. A flat, straight-on crop increases perceived quality — and PerspectiveFix delivers that from a phone photo.
Old documents, newspaper clippings, and manuscript pages scanned with a phone camera are rarely flat. This tool handles even heavy distortion without degrading the underlying image quality.
CamScanner's free tier adds a watermark to every export. The paid tier removes it — at a monthly cost. Your scans also go to their servers.
PerspectiveFix is free with no watermark, no account, and no upload. The tradeoff is that it's a web tool, not a native app — so camera integration isn't built in. You take the photo, then open it here.
For most desktop and laptop use cases, that's a non-issue.
The entire tool is a single HTML file — HTML5, CSS, and vanilla JavaScript. No frameworks, no backend, no CDN dependencies for core functionality.
The perspective math uses a homography matrix computed from the four corner coordinates. Rendering uses the Canvas 2D API with drawImage() and pixel-level manipulation for filters. Web Workers handle the heavier processing to keep the UI responsive.
It's intentionally minimal — which is why it loads instantly and works offline after the first visit.
PerspectiveFix is an independent project by Oathan Rex — a developer who got tired of paying for basic utility tools and decided to build the ones he actually needed.
If it's saved you time, a coffee goes a long way toward keeping it running and updated.