PDF Overlay

Stamp one PDF on top of another as a foreground or background layer. Perfect for letterheads, logos, and certificate templates. 100% in your browser — your files never leave your device.

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PDF overlay is the process of stamping one PDF directly on top of another so that both documents appear on the same pages at once. OneClickPDF's overlay tool runs entirely in your browser — your base PDF and overlay PDF are never sent to any server. Upload a base document and an overlay PDF such as a letterhead, logo, watermark, or certificate template, choose whether it sits in the foreground or background, set the opacity, and download a single composited PDF. It is completely free, needs no account, and your files never leave your device.

How it works

How to Overlay Two PDFs in 3 Steps

Three steps. Add your overlay PDF, choose a layer position and opacity, preview the result, and download — all in your browser.

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Step 1: Upload Your PDFs
Upload your base PDF — the document you want to overlay onto — then add your overlay PDF, the letterhead, logo, watermark, or template you want to apply. Both files are read entirely within your browser and are never transmitted to any external server. File size is limited only by your device's available browser memory.
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Step 2: Choose Layer Position and Set Opacity
Choose whether the overlay sits as a background layer (behind the base content — ideal for letterheads and borders) or a foreground layer (on top of the base content — ideal for watermarks and stamps). Set the opacity from 0 to 100% to control how subtle or solid the overlay appears. If your overlay PDF has fewer pages than your base document, keep the Repeat overlay option on so the last overlay page is stamped across the remaining pages automatically. A live page-1 preview shows the result before you download.
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Step 3: Download Your Overlaid PDF
Click Apply Overlay & Download. Both documents are composited entirely inside your browser, so no files are stored on any server. The output is a single PDF with the overlay applied — the page count matches your base document — ready to share, send, or archive.

Everything You Need to Overlay PDFs

Foreground and background layers, opacity control, and an automatic repeat option — all running entirely in your browser, with your files staying on your device.

Foreground and background layers

Choose whether the overlay sits on top of your base content (foreground) or behind it (background). Letterheads and logos usually work best as background layers — they appear on the page without obscuring the document text. Watermarks and approval stamps often work better as foreground layers. The tool defaults to background and switches with one click.

Opacity control

Adjust how transparent or solid the overlay appears with a 0–100% slider. Set a low opacity for a subtle watermark effect, a medium opacity for a branded letterhead that stays readable, or full opacity for a solid stamp. The opacity applies to the overlay layer only, so your base content is never dimmed.

Repeat overlay across pages

If your overlay PDF is a single page — a letterhead template, for example — but your base document has many pages, the repeat option applies the last overlay page to every remaining base page automatically. Leave it on to brand an entire report in one step, or switch it off for strict page-by-page matching.

Live page-1 preview

Before you download anything, a live preview composites page 1 of both PDFs at your chosen layer position and opacity. Confirm the overlay lands where you expect and is as subtle or solid as you want, then download — no guesswork.

100% browser-based processing

Both PDFs are processed locally inside your browser using client-side computation. Nothing is uploaded to any external server at any point — which is critical for documents that may contain confidential information such as internal reports, client contracts, patient records, or financial statements.

No account, no ads, no limits

Open the tool and start working immediately. No sign-up, no email confirmation, no usage caps, and no advertising interrupting the workflow. Process as many overlaid PDFs as you need, with file size bounded only by your device's available browser memory.

Why Use OneClickPDF to Overlay PDFs?

Privacy-first by design. PDF24 processes your files on its servers and Adobe locks overlay behind a paid subscription. OneClickPDF never uploads anything. Both the base document and the overlay PDF are composited inside your browser using client-side PDF processing, so no third party ever sees your document — which matters when you are branding contracts, financial reports, medical records, or anything confidential.

Opacity control most free tools lack. A 0–100% opacity slider lets you dial in a faint watermark, a readable branded letterhead, or a solid stamp. PDF24, the main free competitor that offers overlay at all, has no opacity control.

See the result before you download. The live page-1 preview composites your two PDFs at the chosen layer position and opacity. You are not guessing — switch foreground to background or nudge the opacity and the preview updates instantly.

Truly free, with no hidden limits. There is no daily cap, no hourly restriction, no file count limit, and no watermark added by us. Overlay as many PDFs as you need, at any time, for free.

Common Uses for PDF Overlay

Adding a company letterhead as a background layer across an entire report, proposal, or contract — the letterhead appears on every page without changing the original content
Certificate templates — overlay a decorative border or official seal template over a blank or pre-filled certificate PDF, adjusting layer position and opacity as needed
Watermarking documents — stamp Confidential, Draft, or For Review across every page using a foreground layer at reduced opacity, so the watermark stays visible without obscuring the text
Adding logos to existing PDFs — position your logo within a full-page overlay PDF, then stamp it onto invoices, order confirmations, or reports without recreating the document
Approval and signature stamps — overlay official approval stamps or date stamps over finalized documents as a foreground layer before archiving or distributing
Designing a single-page brand template and applying it as a background across every page to keep internal and external reports visually consistent — then add a text watermark if you need one

Why choose ours?

Private, instant, unlimited

Most competitors either don't offer PDF overlay or upload your files to their servers. We process everything in your browser.

Feature	Sejda	iLovePDF	SmallPDF	PDF24	Adobe	Ours
PDF-on-PDF overlay	✗	✗	✗	✓	✓ Paid	✓
Free & unlimited	—	—	—	✓	✗ $23/mo	✓
No account needed	—	—	—	✓	✗	✓
Files stay in browser	—	—	—	✗	✗	✓
No ads or interruptions	✗	✗	✗	✗	✗	✓
Foreground & background	—	—	—	✓	✓	✓
Opacity control	—	—	—	✗	✓	✓
Auto-repeat overlay	—	—	—	✓	✓	✓
No file size limit	—	—	—	✗ 500MB	✗	✓

Competitor information was accurate at time of publication and may have changed.

Finished overlaying? add a text watermark stamp a custom text mark across every page, or merge, compress, or sign your PDF. All tools run in your browser, no account required.

Frequently Asked Questions

What is PDF overlay?

PDF overlay is the process of stamping one PDF on top of another so that both appear simultaneously on the same pages. The overlay PDF sits either in front of or behind the base document depending on the chosen layer position. It is commonly used to apply letterheads, logos, watermarks, certificate borders, and approval stamps to finished documents without editing the original content. The result is a single PDF with both documents composited together, keeping the same page count as the base document.

How do I overlay two PDFs online for free?

Upload your base document to OneClickPDF's Overlay tool, then add the overlay PDF you want to apply. Choose whether the overlay should appear as a foreground or background layer, set the opacity level, and keep Repeat overlay on if you want a shorter overlay applied across every page. Click Apply Overlay & Download. Everything runs inside your browser with no server upload, no account required, and no file size cap beyond your device's available memory.

What is the difference between PDF overlay and PDF merge?

PDF merge combines documents sequentially — it adds the pages of one PDF after the pages of another, making a longer document. PDF overlay places one document on top of another, so both are visible on the same page at the same time. Use merge to combine separate reports into one file. Use overlay to apply a letterhead, logo, or watermark to an existing document without changing its page count or content structure.

What is the difference between foreground and background overlay in a PDF?

A foreground overlay sits on top of the base document content, appearing over the text and images. A background overlay sits behind the base content, appearing underneath it. For letterheads and decorative borders, the background layer typically works best because the document text remains fully readable in front of it. For watermarks and approval stamps, a foreground layer at reduced opacity ensures the stamp is clearly visible across the page. OneClickPDF's overlay tool defaults to the background layer and lets you switch with one click.

What does opacity control do in PDF overlay?

Opacity control determines how transparent or solid the overlay layer appears on the final page. A low opacity setting, for example 20–30%, makes the overlay very faint, which is useful for subtle watermarks or lightly branded backgrounds that should not distract from the document content. Full opacity gives the overlay complete visual weight, suitable for logos or stamps that need to stand out. OneClickPDF provides a 0–100% opacity slider applied to the overlay layer.

What does the repeat overlay option mean?

Repeat overlay handles the case where your overlay PDF has fewer pages than your base document. If your overlay is a single-page letterhead template and your base document has twenty pages, repeat overlay stamps that page across all twenty base pages automatically. When the option is off, the overlay is applied only to base pages that have a matching overlay page — so a one-page overlay would land on page one only. The option is on by default and is toggled with a single switch in the tool settings.

Can I add a letterhead to every page of my PDF automatically?

Yes. Design or export your letterhead as a PDF, then upload it as the overlay in OneClickPDF's Overlay tool. Set it as a background layer so it appears behind your document text, adjust the opacity if needed, and keep Repeat overlay on to apply it to every page of your base document. Download the result and every page will carry your letterhead without any manual page-by-page processing. The entire operation runs in your browser with no server upload.

Do my files get uploaded to a server when I use PDF overlay on OneClickPDF?

No. Both PDFs are processed entirely inside your browser using client-side computation. Neither the base document nor the overlay PDF is transmitted to any external server at any point. This matters for confidential materials such as internal contracts, client proposals, financial reports, or patient records that should not pass through third-party servers. The composited output is also generated and downloaded locally, so no file ever touches an external system.

Which free online tools support PDF-on-PDF overlay?

Among the major free PDF tools, very few support true PDF-on-PDF overlay. Sejda, iLovePDF, and SmallPDF do not have a PDF overlay feature at all. PDF24 offers free overlay but processes files on its servers, shows advertising, and has no opacity control. Adobe Acrobat has overlay capabilities but requires a paid subscription. OneClickPDF is a free, browser-based PDF overlay tool that includes opacity control, a repeat option, and no ads, with files that never leave your device.

Can I use PDF overlay to add a watermark to a PDF?

Yes. Create your watermark as a PDF — for example the word Confidential or Draft on an otherwise blank page — then upload it as the overlay in OneClickPDF's tool. Set it as a foreground layer so it appears over the base document content and reduce the opacity so the watermark is visible without completely obscuring the text underneath. Keep Repeat overlay on to apply the watermark across every page, then download. The result is a watermarked PDF produced entirely in your browser.

Guides & tutorials

How to Overlay One PDF on Top of Another

Stamp one PDF on top of another as a foreground or background layer. Add letterheads, stamps, and templates — free and private in your browser.

Add a Company Letterhead or Background to a PDF

Place your company letterhead behind every page of a PDF. Use PDF overlay to add branded backgrounds to any document — free in your browser.

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