How to sign a PDF online for free (no DocuSign needed)

Image signatures vs. digital signatures — the honest distinction

Two very different things share the same word, and conflating them is the most common reason people overpay for a signing tool.

• Image signature. A picture of your handwritten signature is placed at coordinates on the PDF page, just like signing a piece of paper. There is no cryptographic binding to your identity, no audit trail beyond what the PDF itself records. This is what ScoutMyTool's sign-pdf tool does, and what 90% of everyday paperwork actually needs: vendor agreements you've already negotiated, internal forms, HR documents, letters of authorisation, lease addenda.
• Digital signature (PKI / certificate-based). A cryptographic signature using a public-key certificate issued by a trusted authority. The signature mathematically binds the signer's identity to the exact document contents and produces a tamper-evident audit trail. This is what Adobe Acrobat Sign, DocuSign, and the EU's eIDAS-conformant qualified-signature providers do. The PDF specification itself defines the embedding format (§12.8 of ISO 32000-1, "Digital Signatures")¹; the regulated trust framework around it (eIDAS in the EU, ESIGN/UETA in the US) is what makes such signatures court-recognised.²

When do you need the digital version? Real estate closings, cross-border B2B contracts where the counterparty has specified "qualified electronic signature", regulated industries (pharma, finance, legal e-filing), and any document where a future dispute is foreseeable. For everything else, an image signature is faster, free, and what your counterparty was expecting anyway.

Step-by-step: sign a PDF in your browser

ScoutMyTool's sign-pdf tool runs entirely in your browser using the open-source pdf-lib library. Your PDF and your signature image are read into a sandboxed memory buffer; the signature is drawn into the page content stream; the signed PDF is written back as a download. Nothing leaves your device.

1. Create a signature image (one-time setup). The fastest path: sign your name on a clean white piece of paper, photograph it with your phone in good light, and run the photo through any free background-remover app to make the white background transparent. Save as PNG (preserves transparency cleanly). The same file is reusable forever — produce it once, use it on every PDF.
2. Open the tool. Go to scoutmytool.com/pdf/sign-pdf. Static HTML, no account screen. The upload zone appears within about a second.
3. Drop both files. The PDF and the signature image (PNG or JPG) go in together — the tool picks the right role for each based on extension. JPGs work but cannot have a transparent background, so they'll show as a white box around the signature; PNG with transparency is what you want.
4. Choose the page. Enter the page number (1-based — page 1 is the first page) where you want the signature placed. Multi-page signing is one pass per page in the current version; feed the signed output of pass 1 in as the input to pass 2.
5. Set the coordinates. PDF coordinates use points (72 points = 1 inch) with the origin at the bottom-left of the page. Useful defaults:
   • x=72, y=72, width=150 — lower-left corner, about 2 inches wide. Typical "signature line" on a US-letter document.
   • x=400, y=72, width=150 — lower-right corner, where two-column letterheads usually put the signature line.
   • x=72, y=200, width=150 — about 2.75 inches up from the bottom, useful when the signature line is in the middle of the page.
   Height auto-scales to preserve the signature image's aspect ratio, so you only control width.
6. Click "Sign PDF". The tool embeds the signature image into the chosen page's content stream via pdf-lib's drawImage call. This is not an annotation that can be toggled off — it becomes part of the page itself. The download appears as <your-pdf-name>-signed.pdf.
7. Preview before sending. Open the signed PDF in any viewer. Check that the signature is on the right page, in the right spot, and at the right size. If it's in the wrong place, the original is untouched — re-run with different coordinates.
8. If the PDF is password-protected. The tool refuses to sign an encrypted PDF, because re-saving would silently strip the encryption — a security failure in a signing workflow. Unlock via unlock-pdf, sign the unlocked copy, then re-protect with protect-pdfif you still want a password on the final document.

How ScoutMyTool compares to Smallpdf, iLovePDF and PDF2Go

All four offer image-signature workflows on the free tier (none of them offer true PKI digital signatures without a paid plan — that's a Adobe Acrobat Sign / DocuSign category). The meaningful differences are quota, signup, size cap, and whether your file leaves your device.

Third-party tool quotas are taken from each vendor's public pricing page as of May 2026 and may change.

Related PDF tools on ScoutMyTool

• PDF Form Fill — fill in interactive AcroForm fields before signing.
• PDF Form Flatten — bake filled fields into the page so they can't be changed downstream.
• Add Watermark — drop a visible "DRAFT" or "CONFIDENTIAL" mark on every page.
• Protect PDF — add a password to the signed PDF before sending.
• Unlock PDF — required first step if your source PDF is password-protected.
• Merge PDF — combine the signed document with a cover letter or attachments.

Frequently asked questions

Is this a real "digital signature" with a certificate?

No — and being honest about that distinction matters. ScoutMyTool's sign-pdf tool places an image of your signature on the PDF, the same way you'd sign a piece of paper. For PKI / certificate-based digital signatures (which cryptographically bind the signer's identity to the document and produce tamper-evident, court-recognised audit trails), you need a regulated workflow like Adobe Acrobat Sign or DocuSign. For internal forms, vendor agreements you've already negotiated, and most everyday paperwork, an image signature is what people actually use and what most counterparties expect.

Does it work without a touchscreen or stylus?

Yes. The tool takes a PNG or JPG signature image, so you have several easy ways to produce one: sign a piece of white paper and photograph it, use a free background-remover to make the background transparent, save as PNG. You can also use any drawing app on a laptop touchpad or phone screen, then export as PNG. The signature image is reusable — sign once on paper, photograph once, drop the same PNG onto every PDF that follows.

Is my file uploaded to your servers?

No. The sign-pdf tool runs entirely in your browser using the open-source pdf-lib library. Your PDF and your signature image are read into a sandboxed memory buffer, the signature is embedded into the page content stream, and the signed PDF is written back as a download. Nothing leaves your machine — confirm in your browser's network tab.

Where exactly is (x, y) on the page?

PDF coordinates: origin is the bottom-left of the page, units are PDF points (72 points = 1 inch). x grows rightward, y grows upward. So x=72, y=72 places the signature one inch from both the left edge and the bottom edge — the typical "signature line" location for most letterheaded documents. Width is given in points (height auto-scales to preserve aspect ratio).

Can I sign multiple pages at once?

Not in the current version — sign each page in a separate pass. A multi-page UI is on the roadmap. In the meantime, the signed PDF from pass one becomes the input to pass two, so the workflow is just: sign page 1 → download → re-upload that output → sign page 2 → download.

Can I sign a password-protected PDF?

No. The tool refuses to silently strip encryption from a locked source — signing is supposed to add provenance, not weaken access control. Unlock the PDF first via /pdf/unlock-pdf (you'll need the existing password), sign the unlocked copy, then re-protect with /pdf/protect-pdf if you still need a password on the final document.

Will the signature survive printing, re-saving, or being processed by other PDF tools?

Yes. The signature is embedded as part of the page content stream (a drawImage call inside the page's drawing instructions), not as a removable annotation. It prints exactly where it appears on screen, survives any downstream PDF tool that re-saves the file, and cannot be hidden by simply toggling annotation visibility.