How to merge contract pdfs into a single document
- Step 1Order your contract components first — Decide the final reading order before you start: base agreement, then addenda in execution order, then exhibits/schedules, then signature pages. The merge panel adds files in the order you drop them and has no drag-to-reorder, so the sequence you load is the sequence you get.
- Step 2Drop the base agreement, then each addendum and exhibit — Add files to the PDF Merge dropzone. Each queued file shows its name, size, and page count. Drop them in the right order; if one lands out of place, click the × to remove it and re-add — there is no in-place reorder.
- Step 3Flatten any fillable agreement before merging — If a component is a fillable contract (an AcroForm), run it through PDF Flatten first. Merge copies pages but does not rebuild a working form, so flattening bakes the filled values in as static content that survives the merge intact.
- Step 4Confirm the file count and run the merge — With at least two files queued, click Process. The engine creates a new PDF and appends every page of every source document in order. Processing is local; nothing uploads.
- Step 5Download the unified contract — Save the combined PDF. The output filename is derived from the first file (e.g.
agreement.merge.pdf). The result panel shows the output size and confirms zero bytes were uploaded. - Step 6Paginate or number for the record — For a filing-ready bundle, follow with PDF Page Numbers for continuous pagination, or PDF Bates Numbering for discovery-style
PREFIX000001stamps across the whole assembled set.
What merging preserves vs. what it doesn't
Grounded in how the tool actually works — pdf-lib copies pages into a fresh document. Anything tied to the source document's catalog (not its pages) is not carried over.
| Aspect | Behaviour on merge | What to do about it |
|---|---|---|
| Page content & quality | Preserved exactly. Pages are copied, not rasterised or re-encoded — vector text stays vector, scans stay at original DPI | Nothing — this is the intended behaviour |
| Mixed page sizes | Preserved. Each page keeps its own MediaBox, so A4 and Letter pages coexist in one file | Use PDF Resize only if your DMS requires uniform pages |
| Bookmarks / outline | Not carried over. The merged file has no document outline, even if sources had one | Add navigation with PDF Page Numbers; rebuild bookmarks in a desktop editor if essential |
| Interactive form fields (AcroForm) | Not merged into a working form. Field dictionaries are not reliably reconstructed and same-named fields would collide | PDF Flatten each fillable file first to lock values in as static content |
| Document metadata (title/author) | Not copied. Output uses a fresh, empty metadata block | Set metadata afterward in your reader; this is often desirable for a clean record |
| Existing digital signatures | Invalidated for the assembled file. Any byte change after signing breaks signature coverage | Sign or re-sign the *merged* PDF; verify later with PDF Signature Verifier |
Free vs. Pro limits for contract merges
Real limits from the tier configuration. Free batch merge is gated to two files per run, once per day.
| Limit | Free | Pro |
|---|---|---|
| Files per merge | 2 (once per day) | Unlimited |
| Max size per file | 2 MB | 50 MB |
| Max pages per file | 50 | 500 |
| Upload | None — local only | None — local only |
Cookbook
Real contract-assembly orderings and what the merged output looks like. Because there is no drag-to-reorder, the load order *is* the document order — these examples show the exact sequence to drop files in.
Base agreement + two addenda + exhibit
The standard execution package. Load in chronological/legal order so the merged paper trail reads correctly. Mixed page sizes are fine.
Load order (add each file in this sequence): 1. Master_Services_Agreement.pdf (US-Letter, 12 pages) 2. Addendum_1_Pricing.pdf (US-Letter, 2 pages) 3. Addendum_2_SLA.pdf (US-Letter, 3 pages) 4. Exhibit_A_Scope.pdf (A4, 4 pages — kept as A4) Merged output: MSA.merge.pdf — 21 pages, sizes preserved per page.
Assemble separately signed signature pages
Each party signed their own page and emailed back a one-page PDF. Merge them onto the end of the agreement in counterparty order.
Load order: 1. Agreement_body.pdf (10 pages) 2. Signature_Party_A.pdf (1 page) 3. Signature_Party_B.pdf (1 page) 4. Signature_Witness.pdf (1 page) Result: a single 13-page executed contract. Note: these visual signature pages are images/scans, not cryptographic signatures — merging them is just page assembly.
Flatten a fillable agreement, then merge
A vendor sent an AcroForm contract with filled-in fields. Flatten first so the values survive — merge alone would not preserve a working form.
Step 1: PDF Flatten on Vendor_Form_Contract.pdf
→ Vendor_Form_Contract.flatten.pdf (values baked in)
Step 2: Merge:
1. Vendor_Form_Contract.flatten.pdf
2. Cover_letter.pdf
3. Exhibit_pricing.pdf
Result: filled values appear as permanent text in the bundle.Number the assembled bundle for filing
After merging, add continuous page numbers so the bundle reads as one document for the court or counterparty.
Step 1: Merge → contract_bundle.merge.pdf (38 pages)
Step 2: PDF Page Numbers, bottom-center, start 1
→ Page 1..38 stamped across the whole bundle
Optional: PDF Bates Numbering, prefix CONTRACT-, 6 digits
→ CONTRACT-000001 .. CONTRACT-000038Reverse a merge to extract one exhibit
Counsel needs Exhibit C on its own. Merge is non-destructive of the originals, but if you only have the bundle, pull the range back out.
Bundle: contract_bundle.pdf, Exhibit C is pages 30-34 Use PDF Extract Pages → pages "30-34" → contract_bundle.extract.pdf (5 pages, Exhibit C only) Or PDF Split by Range with "1-29, 30-34, 35-38" for three files.
Edge cases and what actually happens
You expected to drag-reorder the queued files
By designThe merge panel lists queued files with a remove (×) button but no drag handle — files merge strictly in the order you add them. To fix an order mistake, remove the misplaced file and re-add it at the right point, or merge as-is and rearrange afterward with PDF Reorder.
A source contract had bookmarks / a clause outline
Not preservedMerging via copyPages copies page content but not the document outline, so any bookmark tree from the source agreements is dropped. The merged file opens with no outline panel. Add navigational page numbers with PDF Page Numbers, or rebuild bookmarks in a desktop editor if your filing requires them.
A fillable (AcroForm) agreement was merged
Form not preservedInteractive form fields are not reconstructed as a working form in the merged document, and identically-named fields across files would collide. Run each fillable contract through PDF Flatten before merging so the entered values become permanent static text that copies cleanly.
A component PDF requires a password to open
RejectedDocuments that need a user/open password to decrypt their content cannot be read for merging and the file will fail to load. The engine does ignore *permission-only* (owner) encryption, so a print-restricted but openable PDF merges fine. For password-locked files, remove the protection first with PDF Remove Password.
A contract was already digitally signed
Signature invalidatedA cryptographic signature covers a specific byte sequence. Adding that PDF's pages into a new merged file changes the bytes, so the original signature no longer validates against the assembled document. Assemble first, then apply (or collect) signatures on the *final* merged contract; verify with the PDF Signature Verifier.
Free tier: trying to merge a third file
Limit reachedFree merging is capped at 2 files per batch, once per day. Adding a third file shows an upgrade prompt. Workarounds: merge in two passes across two days, or upgrade to Pro for unlimited files at higher size/page caps.
One exhibit exceeds 2 MB or 50 pages on free
Limit reachedEach file on free must be ≤ 2 MB and ≤ 50 pages. A heavy scanned exhibit can trip either cap. Shrink it first with PDF Compress (Aggressive), or upgrade to Pro (50 MB / 500 pages per file).
Mixed page sizes look inconsistent in the bundle
ExpectedEach page keeps its original size, so an A4 exhibit after Letter pages is normal and intended (no content is scaled or cropped). If your document management system demands one uniform size, run the merged file through PDF Resize to a single target like A4 or Letter.
You want the originals' title/author metadata kept
Not copiedThe merged PDF is built fresh and does not inherit the source files' title, author, or creation date. This is usually preferable for a clean record. Set whatever metadata you need afterward in your PDF reader.
Frequently asked questions
Will merging change my contract's formatting or quality?
No. Each page is copied exactly from its source PDF — no re-rendering, no image re-encoding. Fonts, vector text, scanned exhibits, stamps, and page layouts are preserved at their original quality and resolution. The merge only concatenates pages; it never touches the content within them.
Can I reorder the files before merging?
Not inside the merge panel — there is no drag-to-reorder. Files combine in the order you add them, so load the base agreement first, then addenda, exhibits, and signature pages in sequence. If a file lands out of order, remove it and re-add it. Alternatively, merge in any order and rearrange the result with PDF Reorder.
Are bookmarks from the original agreements preserved?
No. The merge copies pages but not the document outline, so bookmark/clause-navigation trees from the source PDFs are dropped — the merged file opens with no outline. For navigation, add page numbers with PDF Page Numbers, or rebuild bookmarks in a desktop PDF editor if your filing process needs them.
What happens to a fillable contract form when I merge it?
Interactive form fields are not preserved as a working AcroForm in the merged output, and same-named fields across files would conflict. Flatten each fillable file first with PDF Flatten — this converts the filled values into permanent static content that copies through the merge intact.
Is it safe to merge confidential or privileged contracts in a browser?
Yes. The merge runs entirely in your browser using pdf-lib — no file data is transmitted to any server. Only an anonymous usage counter (no file content) is recorded when you are signed in, which you can opt out of. For privileged or NDA material this is the relevant point: there is no upload, so no server-side exposure surface.
How many contract PDFs can I merge at once?
Free merges combine 2 files per batch, once per day, with each file up to 2 MB and 50 pages. Pro removes the count cap (unlimited files) and raises the per-file limits to 50 MB and 500 pages — appropriate for large scanned exhibit sets and full closing binders.
Will an existing digital signature still be valid after merging?
No. A digital signature covers a specific set of bytes; merging produces a new file with different bytes, so the original signature no longer validates against it. The correct order is to assemble the contract first, then sign (or collect signatures on) the final merged PDF. You can confirm validity afterward with the PDF Signature Verifier.
Can I merge a password-protected agreement?
Only if it does not need a password to open. The engine ignores permission-only (owner) restrictions, so a print- or copy-restricted but openable PDF merges fine. A file that requires a user/open password to decrypt its content can't be read for merging — remove the password first with PDF Remove Password.
My exhibits are different page sizes — will they get squashed to one size?
No. Each page keeps its own dimensions, so an A4 exhibit after US-Letter pages stays A4 — nothing is scaled or cropped. If you specifically need one uniform size for a court or DMS, run the merged file through PDF Resize to a single target.
How do I add continuous page numbers across the whole bundle?
Merge first, then run the result through PDF Page Numbers for sequential pagination (choose position and start number), or PDF Bates Numbering for discovery-style PREFIX000001 stamps. Numbering the merged file (not each component) keeps the sequence continuous.
Can I undo a merge or pull one exhibit back out?
Your original files are never modified — merging always produces a new download. If you only have the combined bundle and need one exhibit, use PDF Extract Pages to pull a page range into a new file, or PDF Split by Range to break the bundle into sections.
Does merging carry over the original documents' author and title?
No. The merged PDF is created fresh with empty metadata rather than inheriting any single source file's title, author, or dates. For a clean legal record this is usually what you want; set any metadata you need afterward in your PDF reader.
Privacy first
All PDF processing runs locally in your browser using PDF-lib and pdf.js. No file is ever uploaded — only metadata counters are saved for signed-in dashboard stats.