Make a seal, stamp a PDF
Use this when a contract needs a seal and your carved stamp and ink pad are somewhere else. Type a name, get a transparent PNG, and drop it onto a PDF or image. Your files stay in this browser.
What this tool does
A seal carries a name and gets pressed onto paper. The mark it leaves is called an impression. This page draws that mark on screen. The result is a PNG with a transparent background, so whatever sits under the seal still shows through.
There are two ways to use it. Download the seal and use it elsewhere, or open a PDF or image right here and stamp it. Both live on the same screen.
Step by step
- Open the seal tab and type a name. The preview updates as you type.
- Pick a shape: round, square, or oval.
- Pick a text direction. Vertical reads right column first, the way carved seals do.
- Set the font, the ink color, the border width, and the size in millimetres.
- Download the PNG. The background is transparent.
- Switch to the stamping tab and pick a PDF or an image.
- Drag the seal on the preview, then set size, opacity, and angle.
- Export. The stamped file downloads straight from this page.
How it actually behaves
- Text size is chosen for you. The tool divides the space left by the border across rows and columns, and rounds shapes get less room than squares because the corners are cut off.
- Vertical layout uses one column up to three characters, two up to six, three beyond that. Horizontal layout uses one row up to two characters, two columns up to four, three beyond that.
- Sizes run from 5mm to 60mm. The exported PNG is drawn at 300dpi.
- Cutting a photo removes every pixel whose red, green, and blue all sit above the threshold. The default threshold is 200 and you can move it between 100 and 250.
- A PDF can be stamped on many pages at once. Stamp every page, or type ranges such as 1-3, 5. Reversed or out of range numbers come back as an error instead of being dropped silently.
- Rotation is baked into the seal image. Rotating inside the PDF would shift the centre, and then the exported spot would not match what you saw.
- Fonts are six SIL Open Font License families plus your device font. We do not host font files. Your browser fetches them from Google Fonts, and the device font makes even that request disappear.
- The server only learns that a step happened once. No name, no file name, no document content.
- Missing on purpose: seal registration, signing certificates, text curved along an arc, placing several seals at once, undo, saved presets, and opening password protected PDFs.
Practical tips
- Two or three characters look best in a round vertical seal. Longer names read better in a square.
- Lower the opacity a little when the seal sits over text. Letters showing through is what sells it.
- A border near 1mm works. Thicker shrinks the name, thinner breaks up in print.
- Photograph a real impression on white paper in even light. Shadows survive even a low threshold.
- Save the PNG once and upload it next time. That skips setting everything up again.
Seals and the law
Making a seal in someone else's name can be a crime in Korea. Article 239 of the Criminal Act punishes forging or misusing another person's seal or signature with up to three years of imprisonment. Make seals in your own name only.
What you make here is not a registered seal. Article 6 of the Enforcement Decree of the Seal Certificate Act sets registered seals at 7mm to 30mm per side, and that rule applies to physically carved stamps filed with a government office. This screen shows the range for reference only.
Article 3 of the Digital Signature Act says an electronic signature is not denied effect merely because it is electronic. That is not a guarantee from us. This tool draws an image on your document. Legal effect comes from your agreement and the applicable law.
When you get stuck
- Boxes instead of letters means the font has not arrived yet. Wait a moment or pick the device font.
- Export says there is no seal. Type a name in the seal tab, or cut one out of a photo first.
- The PDF will not open. Password protected files are not supported. Remove the password first.
- The seal prints blurry. Rebuild it at a larger size instead of stretching it on the page.
- Only one page got stamped. Turn on every page, or type the page numbers you want.