How to Sign a PDF Online — Free, No Software, No Watermark

A contract arrives as a PDF and the next move is "sign and send back." The annoying way: print, sign, scan, email. The right way: open the PDF in a browser, draw your signature with a finger, click where it should go, download. Fifteen seconds, no app, no account. Here's how it works.

When you actually need to e-sign a PDF

Real cases: NDAs from new clients, employment offer letters, vendor contracts under $50k where the qualified e-signature isn't required, lease agreements between friends, school permission slips, any document a real human needs to acknowledge but the workflow doesn't justify a $20/month DocuSign seat.

A drawn signature embedded in a PDF carries the same legal weight as a hand-written one on paper — including the fact that it can be forged with a screenshot. For anything that's legally critical, you want a qualified e-signature (eIDAS in the EU, ESIGN in the US, similar regimes elsewhere) backed by an identity provider. For everything else, a visual signature on a PDF is what people've been emailing each other for fifteen years.

The fastest decision rule

If the document says "qualified electronic signature" or names a specific identity provider, use that provider. Otherwise a drawn signature on a PDF is what the other side expects.

How to sign a PDF online, step by step

Open the Sign PDF tool

Go to convertpdfgo.com/sign. No account, no email, no installation. Page loads in under a second.

Drop the PDF in

Drag the file onto the upload area or click to pick it. Up to 30 MB without a queue. Encrypted in transit (TLS 1.3), encrypted at rest, deleted within one hour.

Build a signature

Three modes. Draw — sign with a mouse or finger on the canvas; works on phones and tablets. Type — enter your name and we render it in a cursive font. Upload — drop a PNG of an existing signature (transparent background works best).

Click on the page to place it

The PDF page preview is interactive. Click anywhere on the page and the signature appears at that position. Pick a different page from the thumbnail row if you need to sign on page 5 instead of page 1.

Download the signed PDF

Click Sign PDF. The server stamps your signature image onto the chosen page at the exact coordinates you picked, then sends back a fresh PDF. Open it in any reader to confirm.

What we do under the hood

Behind the scenes, the signed PDF is generated by pdfcpu, a pure-Go PDF processor we run server-side. Your signature image gets stamped onto the chosen page at coordinates measured from the page's bottom-left corner, in PDF points (1 pt = 1/72 inch). We don't rasterise the rest of the page — only the signature is added, so the original PDF's text remains selectable and searchable.

For the drawn signature, your canvas strokes are exported as a PNG with a transparent background, then uploaded alongside the PDF. The typed signature renders the same way: name → cursive font → canvas → PNG. From the server's perspective there's no difference between the three input modes — it just receives an image and stamps it.

Common signing problems and how to avoid them

The signature comes out too small or too big

We default to a 180-point-wide signature (≈ 2.5 inches), which fits a standard signature line. If yours is too small, draw on a larger area of the canvas — pdfcpu scales the image to width and keeps the aspect ratio.

The signature lands in the wrong spot

The click is the bottom-left anchor of the signature. If it lands above where you wanted, click lower; the preview updates instantly so you can re-click before submitting.

The drawn signature has a white box around it

That happens with uploaded JPGs because JPEG can't store transparency. To get a clean signature with no box, upload a PNG with a transparent background, or use the draw / type modes — both generate PNGs with transparency by default.

The PDF is password-protected

You can't sign a file you can't open. Remove the password first via our protect tool (set to "remove"), sign, then re-add the password if needed.

Privacy and the legal weight of a drawn signature

Three things on privacy: files go over TLS 1.3, files are encrypted at rest while we process them, and files (input PDF, signature image, output PDF) are deleted within one hour. We don't look at your documents.

On legal weight: a visual signature on a PDF is generally accepted for everyday business — same legal status as a hand-written signature scanned to a PDF. For qualified signatures backed by identity verification (legally distinct, sometimes required for property transfers, government filings, or high-value contracts), you need a dedicated provider — DocuSign, Adobe Sign, or a national e-ID provider in your country.

If the document is high-stakes

Sign it here for speed, but back it up with password protection and consider following up with a wet-signed or qualified-e-signed copy. A drawn signature is fine for "please confirm you agree"; it's thin for contracts that might end up in court.

How we compare to other free PDF signing tools

Feature	convertpdfgo	Smallpdf (free)	iLovePDF (free)
Sign-up	None	After 2/day	Optional
Watermark	None	None	None
Draw / Type / Upload	All three	Two	All three
Click-to-place signature	Yes	Yes	Yes
Auto-delete window	1 hour	Vague	2 hours

Frequently asked questions

Will the recipient see the signature even if they don't have my font?

Yes — the signature is embedded as an image, not text. Anyone with a PDF reader sees the exact pixels you drew.

Can I sign on multiple pages?

One page per pass. Run the signed PDF through the tool again to add a signature on another page.

What about signature blocks like 'Signed by: ___ on ___'?

Add a quick watermark with the date and your name, then sign on top. Two passes, but you end up with the same look as DocuSign.

Can I sign on a phone?

Yes — the drawing canvas works with touch. Tablets give the best result because there's more room, but a phone in landscape works fine.

What file size can I sign?

30 MB per upload as a guest, 50 MB when signed in.

Are signed PDFs accepted by my company's compliance team?

Depends on the company. Most accept visually-signed PDFs for internal documents and routine vendor contracts. For audit trails, check with compliance — they may require a qualified e-signature provider.

Is there a usage limit?

No. Free, no daily cap, no sign-up wall, no watermark.

What to do next

One-click follow-ups

After signing, you can password-protect it, stamp a date, bundle it with attachments, or compress it before emailing. All free.

Or browse our full list of 49 free PDF tools.