Adobe Acrobat Pro costs $23.99 per month. If you need to sign a PDF once a week — or once a month — that's an absurd price to pay. The good news is that signing a PDF for free is a solved problem, and several free tools do it just as well.
Here are the four best ways to sign a PDF without Adobe, with an honest look at what each one can and can't do.
Why people look for Adobe alternatives
Adobe Acrobat is the industry standard for PDF work, but it has real problems for everyday users:
- Expensive subscription: At $23.99/month for Adobe Acrobat Pro, signing the occasional contract or lease costs more than the document itself is worth in time.
- Feature bloat: Most people need to sign PDFs and occasionally annotate them. Acrobat bundles in dozens of features they'll never use.
- Account required for everything: Even basic Acrobat functions require an Adobe account and often prompt you to upgrade.
- Free Reader is crippled: The free Adobe Reader app lets you read PDFs and sign documents that have pre-set signature fields — but for a PDF without those fields (which is most documents you receive), you need a paid subscription.
4 free ways to sign a PDF without Adobe
| Method | Price | Download needed? | Watermarks? | Encrypted storage? | Best for |
|---|---|---|---|---|---|
| PrimeDocu | Free | No — browser-based | None | Yes — AES-256 | Any device, privacy-conscious users |
| macOS Preview | Free (built-in) | No — already on Mac | None | No cloud storage | Mac users who prefer offline |
| Smallpdf | Free (limited) | No — browser-based | None (free tier) | Temporary cloud only | Occasional use, browser-only |
| DocuSign | Free basic plan | No — browser or app | None | DocuSign cloud | Sending documents to others for signature |
Method 1 — PrimeDocu (best overall free option)
PrimeDocu is a browser-based document app that works on Windows, Mac, Android, iPhone, and any other device with a modern browser — no download, no app store required.
How to sign a PDF in PrimeDocu:
- Go to PrimeDocu in your browser and upload the PDF.
- Open the document and tap the signature tool.
- Place your signature — draw it with your mouse or finger, type your name, or upload an image of your existing signature.
- Position the signature on the document and adjust the size.
- Download the signed PDF. The signed document is also automatically saved to your encrypted vault.
What makes it stand out: The signed document is stored in AES-256-GCM encrypted storage, with the key on your device — not on PrimeDocu's servers. No watermarks on the free plan. You also get 10 free AI credits per month to summarise or analyse the document before signing, which is genuinely useful for contracts.
Method 2 — macOS Preview (best for Mac users who want offline)
macOS Preview is built into every Mac and can sign PDFs without any additional software or account.
How to sign a PDF in Preview:
- Open the PDF in Preview (double-click it).
- Click the Markup toolbar button (pencil icon) or press Shift+Cmd+A.
- Click the Signature button (the squiggly line icon).
- Create a new signature: draw it on your trackpad, sign on paper and hold it to the camera, or type it using a font.
- Click and drag to place the signature. Save the file.
Limitation: Preview only works on Mac, and there's no cloud storage — the signed file stays where you put it on your Mac. If your laptop is lost or your drive fails, the signed copy is gone unless you manually back it up.
Method 3 — Smallpdf
Smallpdf is an online PDF toolkit that includes a signature tool. The free tier allows a limited number of tasks per day — in practice, this is usually sufficient for occasional signing.
How it works: Upload the PDF at smallpdf.com, use the eSign tool to add your signature, and download the signed file. No account required for basic use.
Limitation: Free users are limited in how many tasks they can perform per day. Smallpdf stores files temporarily on its servers before deletion — not ideal for highly sensitive documents.
Method 4 — DocuSign (best for sending to others)
DocuSign's free plan lets you sign documents and send up to three documents per month for others to sign. It's more formal than the other tools and better suited to workflows where multiple parties need to sign in sequence.
Best for: Situations where you need to send a document to another person for their signature and want an audit trail showing who signed and when — useful if you need the signature to be legally binding.
Limitation: Three sent documents per month on the free plan is a tight limit. For signing documents sent to you, the other tools are faster and simpler.
Frequently asked questions
What is the best free alternative to Adobe Acrobat for signing PDFs?
PrimeDocu is the strongest free alternative — it works in any browser, requires no download, adds no watermarks, and includes encrypted storage for your signed documents. macOS Preview is excellent for Mac users who want a completely offline option. Smallpdf is a solid browser-based option but limits free users to a small number of tasks per day.
Can I sign PDFs in a browser without Adobe?
Yes — PrimeDocu and Smallpdf both let you sign PDFs entirely in a browser without any software installation. Open the site, upload your PDF, place your signature, and download the signed file. PrimeDocu additionally stores the signed document in an AES-256 encrypted vault, so you always have a secure copy.
Does the free Adobe Reader let you sign PDFs?
Adobe Reader (the free version) allows you to add a typed or drawn signature to PDFs that have been specifically prepared for signing with signature fields. For PDFs without pre-set signature fields — which is most documents you receive — you need Adobe Acrobat Standard or Pro, which costs $12.99–$23.99 per month. This is why most people look for alternatives.