Free online NBIB to XLS converter

A literature-review team may need citation records in an Excel worksheet for screening, sorting, or sharing with colleagues who do not use a reference manager. Converting a PubMed export to .xls makes the records available in the legacy Excel format, but field mapping must be checked after conversion.

What the NBIB format is

NBIB is a tagged plain-text bibliographic format used by PubMed and other NCBI services to export references. PubMed creates it through Send to → Citation manager; files commonly use the .nbib extension and contain tags for fields such as PMID, title, authors, journal, publication date, DOI, abstract, and publication type.

Reference managers including Zotero and EndNote can import NBIB or its tagged MEDLINE structure. NBIB is not a spreadsheet: each citation consists of tagged lines, and a record can contain multiple authors, keywords, identifiers, and other repeated fields.

What the XLS format is

XLS is the binary Microsoft Excel 97–2003 workbook format. Microsoft Excel, LibreOffice Calc, and compatible spreadsheet programs can open it for filtering, sorting, column editing, screening, and tabular sharing.

The format is useful when a recipient or older system specifically requires .xls. It does not preserve all bibliographic relationships and is less suitable than NBIB, RIS, BibTeX, or a reference-manager library for later citation-management work.

Convert NBIB to XLS online

1. Open the NBIB-to-XLS converter on 101convert.com.
2. Select the .nbib file from your computer.
3. Choose XLS as the output format and start the conversion.
4. Download the generated .xls file and open it in Excel or LibreOffice Calc.

This method requires no installed software and is available free on 101convert.com. Because the conversion translates tagged records into worksheet columns, compare several rows with the original NBIB file before using the workbook for screening or analysis. Do not upload records containing confidential information unless the service’s current privacy terms permit that use.

Convert through a reference manager

1. In Zotero, choose File → Import and select the NBIB file. If NBIB is not listed, use the MEDLINE import option.
2. Review the imported references, remove unwanted records, and resolve duplicates if necessary.
3. Use File → Export Library and export the selected records as CSV, if available.
4. Open the CSV in Excel or LibreOffice Calc, verify the delimiter and UTF-8 character encoding, and save it as Excel 97–2003 (*.xls).

EndNote can provide a similar intermediate-file workflow: import the NBIB records, select the required references, and export them with a tab-delimited output style. Open that text file in Excel or Calc, assign the correct delimiter and text encoding, then save it as .xls. Export menus and available styles vary by EndNote version.

Quality and compatibility checks

• Check author names, titles, dates, DOI values, PMID numbers, abstracts, and journal names against the source file. Tags such as FAU, AU, AB, and AID may be renamed, combined, or omitted.
• Multiple authors, keywords, and identifiers may appear in one cell, across several columns, or as repeated rows. A spreadsheet conversion does not guarantee a normalized database structure.
• Preserve the original .nbib file. Editing or resaving the workbook can remove tags and bibliographic structure needed for later import into a reference manager.
• The XLS format supports a maximum of 65,536 rows and 256 columns. Large exports may need to be split or saved as .xlsx instead, if the receiving system accepts the newer format.
• When importing an intermediate CSV or tab-delimited file, select UTF-8 and confirm that accented names, non-English titles, punctuation, and leading-zero identifiers remain intact.