Image Rotator
Turn an image in quarter steps, or straighten a crooked horizon by a fraction of a degree.
Lossless — no pixel is resampled.
For straightening a horizon. This resamples.
Cuts to the largest rectangle with no empty area.
Ignored for PNG.
Drop an image here
or paste a screenshot with Ctrl+V. Nothing is uploaded.
Everything here runs on your device. Nothing you enter is uploaded or stored.
Two quite different jobs share the name “rotate”: turning a sideways photo upright, and levelling a horizon that came out a couple of degrees off. They have different costs and want different controls, so this tool keeps them separate.
How to use it
- Drop an image onto the panel, press Choose images, or paste from your clipboard.
- For a sideways photo, press the quarter-turn buttons. For a crooked one, drag the fine angle slider.
- If the fine angle leaves empty corners, pick a fill or switch on auto-crop.
- Press Download, or use the batch button to rotate a whole selection into a ZIP.
Quarter turns are free, fine angles are not
A 90 degree rotation is a pure rearrangement. Each pixel in the output corresponds to exactly one pixel in the input — nothing is blended, averaged or invented. Rotate a photo four times by 90 degrees and you get back something pixel-identical to what you started with. Use this for any photo that came out of the camera sideways.
Any other angle has to resample. A pixel in the output sits between several input pixels, so its colour is interpolated from its neighbours, and interpolation always costs a little sharpness. The effect from a one or two degree straightening is barely visible, but it is real, and it is why the tool tells you which of the two operations you are currently performing.
If you need 90 degrees, use the buttons rather than typing 90 into the angle field. Same visual result, no resampling.
Why the canvas has to grow
This is the part most rotate tools get wrong, and the mistake is easy to miss.
Picture a photograph on a table. Turn it ten degrees. Its corners now poke outside the rectangle it originally occupied. To hold the rotated image you need a bigger rectangle, and the size follows directly from trigonometry: the new width is the original width times the cosine of the angle plus the original height times the sine, and the new height is the same pair swapped.
A tool that keeps the original canvas size crops those corners away. You lose a wedge from all four, and because photographers tend to place subjects near the edges of a frame, that is often exactly the part you wanted. This tool expands the canvas instead, so nothing is ever silently discarded.
The trade is that expanding leaves four empty triangles. Filling them with white suits documents and scans. Filling them with a blurred, enlarged copy of the image keeps the frame looking complete and works well for photographs on a coloured background. Auto-crop takes the other route and cuts to the largest rectangle that contains no empty area — the geometry for that inscribed rectangle is worked out exactly rather than approximated, because an approximation leaves a visible sliver of background along one edge.
What it does not do
It rotates a flat image and does nothing about perspective, so it will not correct converging verticals in a photo of a building. There is no automatic horizon detection — you set the angle yourself, and the thirds grid on the crop tool is more helpful for judging level than a number is. Very large images are capped at the browser’s canvas limit, which you will be told about rather than left to discover.
Everything happens on your device. No upload, no queue, no limit.
Corner fill options
| Fill | Best for | Note |
|---|---|---|
| Transparent | PNG or WebP output | Comes out black if you save as JPEG |
| White | Scans and documents | Matches paper, reads as intentional |
| Black | Dark photographs | Behaves like a letterbox |
| Blurred edges | Photographs generally | Frame stays filled, no crop needed |
| Auto-crop | Straightened photographs | Loses a little edge, needs no fill at all |
Questions
Does rotating an image lose quality?
It depends entirely on the angle. A quarter turn — 90, 180 or 270 degrees — maps every destination pixel to exactly one source pixel, so the result is identical in quality to the original. Any other angle has to interpolate each pixel from several neighbours, which softens the image very slightly. That is why the quarter-turn buttons are separate from the fine angle slider rather than being the same control.
Why does my image get bigger when I rotate it slightly?
Because a rotated rectangle needs a larger rectangle to contain it. Turn a photo by 10 degrees and its corners now stick out past the original frame, so the canvas has to expand or those corners get cut off. The new size follows from the geometry — width times the cosine plus height times the sine. Tools that rotate in place without expanding are silently cropping your image, and the loss is worst at the corners where subjects often sit.
How do I get rid of the empty corners after straightening?
Three options. Fill them with a solid colour, which suits scans and documents. Fill them with a blurred, scaled copy of the image so the frame stays visually complete. Or turn on auto-crop, which cuts to the largest rectangle containing no empty corner at all — this loses a little of the edges but needs no filling and is usually the right choice for photographs.
Why are my corners black when I chose transparent?
Because you saved as JPEG, which has no transparency. The empty corners have nowhere to store their transparency, so they composite against black. Either pick PNG or WebP, which both support an alpha channel, or choose a solid fill colour instead. The tool warns you about this combination before you download.
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