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Image Straightening
Auto-Straighten Crooked Images
- Auto-detect or manual angle · Live preview
- Photos and scanned documents · Re-process anytime
- JPG, PNG, WebP
Drag and drop an image here
or click to browse · JPG, PNG, WebP, GIF, BMP, AVIF
Why Straighten Images?
Straightening creates professional and properly aligned photos. Tilted images can be distracting and reduce visual quality.
Benefits of Image Straightening
- Professional Appearance:: Create properly aligned, level images.
- Automatic Detection:: Auto-detect rotation angle using edge detection.
- Manual Control:: Fine-tune the rotation angle manually.
- Document Quality:: Straighten scanned documents for readability.
- Quick Fix:: Instantly correct tilted photos and images.
How Image Straightening Works
The tool detects dominant lines and estimates rotation angle, then rotates the image to align horizontal and vertical structures.
Straightening Process
- Edge Detection:: Finds strong edges and candidate lines in the image.
- Angle Calculation:: Computes the correction angle from detected line orientation.
- Rotation Transformation:: Applies rotation to straighten the image.
- Interpolation:: Interpolates pixel values to preserve quality.
- Output Generation:: Produces a straightened image for export.
How to Straighten Crooked Images Online
Automatically detect and correct image rotation using edge detection or manual adjustment.
- Upload image: Upload JPG, PNG, WEBP, or GIF.
- Auto-detect: Use auto-detect to estimate correction angle from edges and lines.
- Manual adjust: Fine-tune rotation with the slider when needed.
- Preview: Review alignment in real time.
- Download: Export in PNG, JPG, or WEBP.
Common Use Cases
Useful for landscape photography, documents, and architecture.
- Landscape Photography: Straighten horizon lines in outdoor scenes.
- Scanned Documents: Fix pages captured at slight angles.
- Architectural Photography: Improve alignment in building photos.
Frequently Asked Questions
How accurate is the auto-detect feature for fixing a tilted horizon?
Auto-detect analyzes dominant edges and lines in your image to calculate the correction angle. It works best when clear horizontal or vertical references are visible — like a horizon, a window frame, or a tabletop edge. For subtle tilts under 1 degree, fine-tune with the angle slider, or drag a line along anything that should be level.
Why does my straightened image have white corners after rotation?
Rotating an image exposes empty triangular areas in the corners that were outside the original frame. "Crop to fill" trims them away for you. With "Keep everything", nothing is cropped and the corners are filled instead — transparent in a PNG, white in a JPEG or WebP.
Does re-straightening a JPEG reduce image quality?
Re-encoding a JPEG after rotation introduces a small amount of compression loss due to pixel re-interpolation. To avoid it, export your straightened image as PNG, which is lossless. For small correction angles the visual difference is usually imperceptible.
Can this tool fix perspective distortion in architectural photos?
Straightening corrects rotational tilt (camera roll) but not perspective distortion caused by pointing the camera upward at a building. If vertical lines converge toward the top of the frame, you need a dedicated perspective or keystone correction tool rather than an image straightener.
How do I straighten a scanned document that was placed at a slight angle?
Upload the scan: the tool looks for the dominant line direction in the document edges or text baselines and applies the correction angle automatically, and "Auto-Detect Rotation" runs it again. If the scan is faint or low-contrast, drag a line along a line of text or the page edge, or set the angle with the slider.
Can I batch-straighten multiple photos at once?
Yes, with Pro. Upload several images and apply the same angle to all of them with "Process All Images"; each one can still be re-processed with its own angle, and the whole set downloads together as a ZIP file. Free straightens one image at a time.
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