twineconvert

free · in-browser · no upload

BibTeX to NBIB
Converter

Drop your BibTeX file. We'll convert it to NBIB right here in your browser, your file never leaves your device.

BIBTEX
to
NBIB

Select your file here to get started

or drop your file here.

Accepts .bib, .bibtex

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

  1. 1

    Drop your file

    Click the dropzone above or drag a BibTeX from your desktop. Files of any size, there's no upload, so there's no upload limit.

  2. 2

    Convert in your browser

    The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.

  3. 3

    Download

    Get your NBIB the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Drop a file, get a converted file.

Formats involved

About BibTeX and NBIB

BibTeX, BibTeX bibliography

BibTeX is the de facto bibliography format for LaTeX since 1985, plain-text entries like @article{key, author={...}, title={...}, journal={...}, year={2024}}. Used by every academic publisher's LaTeX template and supported as an import/export format by Zotero, Mendeley, EndNote, and Papers. Strengths: trivially diff-able in git, scriptable, tooling-rich. Weakness: there's no single canonical spec, so different parsers handle edge cases (special characters, cross-references, @string macros) inconsistently.

How to open

Any text editor (the format is plain text). Reference managers like Zotero, Mendeley, JabRef, BibDesk all read and write it natively.

Full BibTeX format guide →
NBIB, PubMed citation format

NBIB is the National Library of Medicine's citation format for PubMed exports. Structurally identical to RIS with a different tag dictionary (PMID, FAU, JT, AID instead of ID, AU, JO, DO). Reference managers treat .nbib files as RIS-flavored with PubMed-specific extensions. The format ships with PubMed downloads and the major systematic-review tools (Covidence, Rayyan).

How to open

Zotero, Mendeley, EndNote, Papers, all read NBIB natively. Plain text in any editor.

Full NBIB format guide →

Related tools

Convert other files to NBIB

Convert your BibTeX to other formats

How we compare

BibTeX → NBIB vs the alternatives

FeatureUstwineconvertCloudConvertiLovePDFFreeConvertSmallpdf
Files uploaded to a server
Free file size limitNo limit1 GB200 MB1 GB5 GB
Free conversions per dayUnlimited10/dayLimitedLimited2/day
Signup required
Watermark on output
Works offline (after first load)

Last verified May 2026 from each competitor's pricing and FAQ pages. Limits and pricing change frequently.

FAQ

Common questions

Is this BibTeX → NBIB converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert BibTeX to NBIB?

Academic citations in LaTeX papers; reference-manager export. PubMed citation export; systematic review imports. The most common reason to convert is compatibility, NBIB works in places where BibTeX doesn't, or vice versa.

How do I open a BibTeX file in the first place?

Any text editor (the format is plain text). Reference managers like Zotero, Mendeley, JabRef, BibDesk all read and write it natively.

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.