DocCoords
Client-side only • No uploads Open Tool

Docs

Everything you need to understand llx,lly,urx,ury, export placements, and stamp signatures - fully in-browser.

PDF points
Origin bottom-left
Stamp PNG

Getting started

  1. Open Tool and load a PDF (local file).
  2. Create a box on the page where you want the signature/field.
  3. Adjust using drag handles or keyboard nudging (if enabled in your build).
  4. Copy/export the resulting llx,lly,urx,ury coordinates.
Tip: keep a small margin from page edges (e.g., 10–20 points) to avoid printer clipping.

Coordinate system

PDF coordinates are measured in points (1 point = 1/72 inch). The origin (0,0) is typically at the bottom-left of the page.

What do llx,lly,urx,ury mean?

  • llx = lower-left X
  • lly = lower-left Y
  • urx = upper-right X
  • ury = upper-right Y

Example

llx=72, lly=120, urx=220, ury=170
That is a rectangle 148pt wide and 50pt tall.
Watch out: some libraries/tools display coordinates with a top-left origin. DocCoords uses the PDF mental model (bottom-left origin).

Export format

Exported placements are intended to be easy to feed into your backend signing/stamping pipeline. 

{
  "pages": [
    {
      "pageIndex": 0,
      "pageNumber": 1,
      "boxes": [
        {
          "llx": 50, "lly": 716, "urx": 166, "ury": 762
        }
      ]
    }
  ]
}

Page numbering

Decide whether your system is 1-based or 0-based and be consistent. If your pipeline is 0-based, convert on export/import.

Units

Units are PDF points. If your target uses pixels, convert using DPI: px = points * DPI / 72.

Stamping a signature

  1. Upload a PNG signature (transparent background recommended).
  2. Select the target box.
  3. Stamp it to the selected box (or apply across page/all pages depending on your tool options).
Best result: use a transparent PNG cropped tightly around the signature, then scale within the box.

Precision & DPI

Your PDF may render to screen at a zoom scale, but exported coordinates must remain in PDF points. A common source of mismatch is mixing render pixels with PDF points. 

points = pixels / scale
pixels = points * scale
If you ever notice “shifted” stamps, check scale/zoom conversions and page rotation.

Best practices

  • Keep boxes within page bounds (avoid negative coordinates).
  • Use consistent box sizes for a professional look across pages.
  • Prefer snapping guides for alignment (center/edges).
  • Name labels clearly: Signer 1, Initials, Date.
  • Test on 2–3 real PDFs (scanned, digital, rotated) before standardizing.

Troubleshooting

Want to try it now?

Open the tool and place your first box.

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