Annotate image online with clear notes and useful measurements

Paste, drop, or choose a JPG, PNG, or static WebP. Use arrows, text, rectangles, highlights, and numbered steps to explain the image. Select a mark to move or restyle it; download the completed annotations as a PNG. No account is required.

Choose Arrow and drag toward the detail. For Text, type a note, set its font size, wrap width, and optional background, then click the image. Use Select to edit text or drag either arrow endpoint. Short notes usually keep the underlying screenshot easier to read.

Switch to Measure, choose Distance, and drag from the first point to the second. The label shows the straight-line distance in source pixels, including diagonal lines. No reference is needed for pixels. Select the line and drag either endpoint to refine its placement.

Draw Reference line over a segment whose real length you know, enter that length, choose its unit, and confirm the scale. Length equals measured pixels × known length ÷ reference pixels. Units include mm, cm, m, in, ft, and µm. All distance and area labels use the confirmed scale.

A single scale is suitable for a scan, flat drawing, or front-facing planar image with a known reference in the same plane. Strong perspective, lens distortion, or different object depths can invalidate that scale. This tool does not perform perspective correction or infer unknown real dimensions. More decimal places do not make a photo more accurate.

Choose Angle and click a point on the first arm, the vertex, and a point on the second arm. The second point is the vertex; the result is the smaller 0–180° angle in the image plane. Angles need no length calibration. Select the angle to adjust any of its three points.

Choose Rectangle area and drag between opposite corners. The tool measures an axis-aligned rectangle in px², or in squared units after calibration. For example, at 20 px per cm, a 200 × 100 pixel rectangle is 50 cm². It does not trace polygons, tilted rectangles, circles, or irregular boundaries.

Yes. While you annotate image online, switch to Select, then drag the numeric label to a clear spot. Dragging the label only changes its position. Circular handles edit endpoints, and dragging the line or region moves the whole object. Color, stroke, and measurement label size remain editable.

Preview zoom only changes display size, so measurements stay the same. Moving a reference endpoint or changing its length input or unit requires confirmation again; until then, lengths and areas use pixels. Replacing the image clears the scale. After crop, resize, perspective edits, or stitching, check the reference again; old exported numbers are fixed pixels.

Yes. Download PNG combines the original image with completed annotations, measurement lines, angle arcs, numbers, and notes at the source pixel dimensions. Unfinished drafts and selection handles are excluded. The resulting PNG has no editable layers or reusable calibration, so keep editing in the current tab until you are satisfied.

Measurement calculates a length from a known reference inside the picture. Printing to scale arranges an image on paper at a length you specify. Use the separate print tool when you need a paper template or a chosen output size; entering a print size does not establish the real dimensions of an unknown object.

Image editing, measurement calculations, undo history, and PNG export run locally in your browser. The image is not uploaded for processing. The wider website uses ads and analytics. Hide sensitive information with opaque redaction before sharing; a translucent highlight is only an emphasis mark.