Fix a crooked photo in seconds. Rotate it by any angle down to a tenth of a degree while a grid shows what is level, or simply draw a line along the horizon or a wall and let the tool calculate the angle. The empty corners are cropped away automatically.
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Drag along the horizon or any edge that should be level or vertical.
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How to use the Straighten Image
Add your photo by dropping it in, choosing a file or pasting. A tilted sample is shown first.
Level it with the horizon tool: click Draw level line and drag along the horizon, a table edge or a wall. Vertical lines work too.
Fine-tune with the slider or the ±0.1° and ±1° buttons while checking the grid.
Choose the edges: keep Auto-crop on to remove the empty corners, or turn it off and pick a corner fill.
Download the straightened image as JPG, PNG or WEBP.
How much does straightening crop?
When an image of width w and height h is rotated by an angle θ, the largest rectangle of the same shape that still fits inside it is scaled by
k = min( w ÷ (w·cos θ + h·sin θ), h ÷ (w·sin θ + h·cos θ) )
Auto-crop uses exactly this rectangle, centered. The table shows how much of each side remains for common photo shapes:
Angle
3:2 landscape
4:3 landscape
1:1 square
16:9 landscape
0.5°
98.7%
98.9%
99.1%
98.5%
1°
97.5%
97.7%
98.3%
97.0%
2°
95.1%
95.6%
96.7%
94.2%
3°
92.8%
93.6%
95.2%
91.6%
5°
88.7%
89.9%
92.3%
86.9%
10°
80.3%
82.2%
86.3%
77.3%
A slightly tilted handheld photo is often off by just a degree or two, so the loss is small. If you need every pixel, turn Auto-crop off and fill the corners instead.
Tips for a perfectly level photo
Use the true horizon for seascapes and open landscapes. Hills and shorelines are rarely level, so they make poor references.
In architecture, use vertical lines near the center of the frame, such as a door frame or the edge of a building. Lines near the edges can lean because of lens perspective, which rotation cannot fix.
Indoors, a table edge, window sill or the line where the wall meets the ceiling works well.
Draw a long line. The longer the reference, the more precise the measured angle. You can draw again on the corrected preview to refine it.
Scanned documents straighten best along a line of text or the edge of the page.
Frequently asked questions
How do I straighten a crooked photo?
Add the photo, click Draw level line and drag along something that should be horizontal, such as the horizon, a shelf or a window sill. The tool measures the tilt and rotates the image by the opposite angle. Check the grid, adjust with the ±0.1° buttons if needed, and download.
Why does straightening crop my photo?
Rotating a rectangle by any angle other than 0° or 90° makes its corners stick out, leaving empty triangles in a rectangular frame. Auto-crop keeps the largest rectangle of the same shape that fits inside the rotated image. The larger the angle, the more is cut: on a 3:2 photo each side shrinks by about 5% at 2° and about 11% at 5°.
Can I straighten without losing the corners?
Yes. Turn off Auto-crop and the canvas grows to fit the whole rotated image. Choose transparent corners (PNG or WEBP), white, or any color to fill the empty triangles.
Does the horizon tool work with vertical lines?
Yes. If the line you draw is closer to vertical than horizontal, the tool makes it perfectly vertical instead. That is useful for buildings, door frames and poles.
Does rotating reduce image quality?
Rotation by an arbitrary angle resamples the pixels, which softens the image very slightly; this is unavoidable in any editor. Saving as PNG avoids extra compression. With Auto-crop the result is a little smaller than the original unless you enable scaling back to the original size.
Which way does a positive angle rotate?
A positive angle rotates the image clockwise and a negative angle rotates it counter-clockwise. If the right side of your horizon is too low, the photo needs a counter-clockwise (negative) correction.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.