Is the original ZIP modified?

No. The original file on your disk is never touched. The tool reads it into memory, builds a new combined archive, and delivers that as a fresh download.

What happens if a new file has the same path as an existing entry?

The conflict policy decides. Rename gives the new file a numeric suffix (file_1.txt, file_2.txt). Overwrite replaces the existing entry. Skip keeps the original and drops the incoming file.

Does it preserve the original compression?

No — the whole output ZIP is re-compressed at the level you pick. Store keeps things fastest; Max gives the smallest output.

Can I add to a password-protected ZIP?

Not in this tool. Decrypt first with Unlock ZIP, add the files here, and if you need encryption again, pass the result through Password Protect ZIP.

Add Files to ZIP

Convert · ZIP

1. Existing ZIP

Drop the ZIP you want to add to

Select a file

2. Files to add

Drop files or a folder to append

Select one or more files

3. Options

Conflict policy

Output compression

The whole output ZIP is re-compressed at this level, including entries from the original archive.

Output filename

.zip

4. Build combined ZIP

Convert ArchiveConvert archives between formats — ZIP to 7z, TAR to ZIP, and more.
Merge ArchivesCombine multiple archives into a single file. Handle filename conflicts automatically.
Split ArchiveSplit a large archive into smaller, independently-openable parts.
Remove from ZIPOpen a ZIP, tick entries to drop, and download a trimmed archive without the removed files.

Add Files to ZIP

1. Existing ZIP

2. Files to add

3. Options

4. Build combined ZIP

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