Image Straighten Tool

Straighten tilted photos by drawing a reference line along the horizon.

Tested tool guide Tested browser tools Checked August 16, 2026

What Image Straighten Tool does and how it behaves

Image Straighten Tool corrects camera roll in a photo by using a line you draw across a feature that should be horizontal. Trace the feature as it currently appears, such as a sloping sea horizon or shelf edge. The tool measures that visible tilt and rotates the image in the opposite direction until the reference is level. A common mistake is drawing the line where the horizon ought to be; the line must follow the tilted horizon that is already in the picture.

How the result is produced

Reading the reference line

The two endpoints of the drawn line establish its angle relative to horizontal. A line rising toward the right represents tilt in one direction, while a line falling toward the right represents tilt in the other. The correction uses the opposite angle. Longer reference lines generally make careful endpoint placement easier because a small positioning error has less influence on the measured slope.

Rotating the photograph

Straightening rotates the photograph as a single flat image so that the chosen reference becomes horizontal. It does not separately reshape objects in different parts of the scene. Rotation also changes the axis-aligned footprint of a rectangular image, so inspect its corners and outermost subjects after correction. Border handling can affect how much of the original edge content remains in the final rectangle.

Good uses

Level a beach, lake, or landscape photograph in which handheld camera roll made a naturally straight horizon slope from one side of the frame to the other.
Correct a slightly skewed scan or overhead photograph by tracing a long printed baseline, table rule, or page edge that was horizontal in the original document.
Remove camera roll from an architectural or interior photograph by following a dependable horizontal feature such as a roofline, shelf, window head, or countertop.

Limits and checks

Confirm that the feature you traced was actually horizontal in the photographed scene. A sloping road, shoreline seen in perspective, pitched roof, or intentionally angled object can produce a technically level line but an incorrectly oriented picture.
Do not use a very short or poorly defined segment when a longer straight feature is available. A few pixels of endpoint error can noticeably change the inferred angle when the guide line spans only a small distance.
Review more than the chosen line. A level horizon does not prove that verticals, nearby edges, or the overall composition are correct. Perspective convergence and lens curvature can make different parts of an image disagree even after camera roll is removed.

Common questions

Should I draw a horizontal line or follow the tilted horizon?

Follow the horizon exactly as it appears in the loaded photograph, placing the endpoints on two well-separated points along the same straight feature. Do not draw the line where you want the horizon to end up. Its current slope is the measurement the tool needs. If no genuine horizon is visible, use another feature known to have been horizontal in the scene.

Will straightening also fix perspective or a curved horizon?

No. Straightening addresses rotational tilt by making one selected reference line horizontal. It does not, by that operation alone, remove converging verticals, keystone distortion, lens distortion, or panoramic stitching errors. If the horizon bows or different horizontal features have different slopes, choose the line most important to the composition and expect the remaining geometric distortion to persist.

References and verification

The behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.