PDFMaxValidate PDF Signature
Need to know if a signed PDF is genuine? This free tool validates the digital signature inside your document, so you can confirm who signed it and whether the file was changed afterward. Upload a signed PDF and PDFMax checks the signature against its certificate, showing the signer's details, the signing time, and whether the signature is still valid. There's no signup and nothing to install — everything runs in your browser on desktop or mobile. It's the quick way to verify a contract, invoice, or official document before you trust or forward it to someone else.
Validate PDF Signature →100% freeNo signupWorks in your browser
Why PDFMax
- Confirms the signer's identity by checking the digital certificate attached to the PDF
- Detects tampering — tells you if the document was modified after it was signed
- Shows useful details like the signing time and certificate information
- Completely free with no signup, no install, and no watermarks
How to validate PDF signature
- Upload your signed PDFDrag and drop the signed PDF onto the page, or click to select it from your device.
- Run the signature checkPDFMax reads the digital signature and validates it against the signer's certificate.
- Review the resultSee whether the signature is valid, who signed the file, when, and if it was changed after signing.
Frequently asked questions
Is validating a PDF signature free?
Yes. Checking a PDF signature on PDFMax is completely free. There's no signup, no subscription, and no watermark added to your file.
Is it safe and private?
Your document is only used to verify its signature, and the process runs in your browser. We don't share your files, so it's safe for contracts and other sensitive documents.
Are there any limits?
No tool limits to worry about — validate as many signed PDFs as you need. Very large files may simply take a little longer to process.
Does it work on mobile?
Yes. PDFMax runs in any modern browser, so you can validate a signed PDF on a phone or tablet just as easily as on a computer.
What does a valid signature mean?
A valid result means the signature matches the document and the file hasn't been changed since it was signed. An invalid result can mean the document was altered or the certificate isn't trusted.
Do I need to install anything?
No. There's nothing to download or install. Just open the page in your browser and upload your signed PDF.