How to Merge Split File Parts Back Together

You received a large file in pieces — `backup.zip.001`, `backup.zip.002`, and so on — or you split one yourself to send it. Now you need the whole thing back. Merging file parts rejoins those segments in order to reconstruct the original file exactly. This guide explains how rejoining works, what you need for it to succeed, and how it fits with splitting.

What merging parts does

Merging concatenates split file segments back into the single original file. Each part is a raw chunk of the original's bytes; joined in the right order, they reproduce the source file perfectly — identical to what was split. It is the second half of the split-and-rejoin process, and useless without all the pieces.

How to merge file parts with this tool

1. Open the File Merger tool.
2. Add all the split parts.
3. Confirm they are in the correct order.
4. Merge and download the reconstructed file.

Everything runs in your browser, so your file is never uploaded.

What you need for a clean rejoin

Reassembly is exact and unforgiving, so:

• Every part must be present. A single missing segment makes the file incomplete and unusable. Confirm you have the full set before starting.
• The order must be correct. Parts join in sequence — 1, 2, 3, … — and the numbering exists to preserve it. Out-of-order parts produce a corrupt file.
• The parts must be intact. A segment damaged in transfer breaks the whole. If the result will not open, a corrupted or missing part is the usual cause.
• Match the split method. Parts made by File Splitter rejoin here cleanly.

Verifying the result

After merging, check the file actually works — open it, or inspect it with File Inspector to confirm it is the type you expect and not truncated. If the original was zipped, Zip Extractor unpacks the rejoined archive. If it was encrypted, Decrypt File restores it with the password.

Merging parts vs. merging documents

A quick clarification, since "merge" is overloaded: this tool rejoins *byte segments* of one split file. It does not combine *different* documents into one — that is Merge PDF for PDFs or Zip Creator for bundling. Use file merger only to reassemble parts that were split from a single original.

Common uses

• Reassemble a file sent to you in parts.
• Rejoin a file you split for transfer or storage.
• Reconstruct a large backup from segments.

Related tools

File Splitter is the essential counterpart — split to send, merge to use. Together they move files that are too big to transfer whole.

Privacy and limits

Merging is fully local — no upload, no file-size cap, nothing stored, offline once loaded. Open the File Merger tool to rebuild your file.