Node.js module to convert excel timestamps to JS dates.

Usage no npm install needed!

<script type="module">
  import exceldate from 'https://cdn.skypack.dev/exceldate';



Codeship Status for floydnoel/exceldate

A Node.js package to convert excel timestamps to JS dates. A simple utility function with no dependencies, exceldate accepts a number directly or stored in a string.


yarn add exceldate
# or
npm install exceldate


Check it out:

const exceldate = require('exceldate')

// use it directly
console.log(exceldate('1').toISOString()) // 1899-12-31T00:00:00.000Z
console.log(exceldate(4242.4242).toISOString()) // 1911-08-12T10:10:50.880Z

// or use it with a callback
exceldate(9000, (err, res) => {
  if (!err) console.log(res.toISOString()) // 1924-08-21T00:00:00.000Z



  • clone/download the repo
  • navigate to the repo: cd exceldate
  • install dev dependencies to test: yarn or npm i

To test run yarn test or npm test


This is free and unencumbered software released "as is" into the public domain, without warranty of any kind. For more information, please refer to the LICENSE file and https://unlicense.org


  • 0.0.3: first stable version
  • 1.0.0: support callback style interface, remove semicolons, updated test framework, updated README
  • 1.0.1: remove old code comment
  • 1.0.2: update README
  • 1.1.0: added testing dev dependency, integrate eslint & prettier, added JSDoc types, friendlier error messages, invalid inputs will now throw an error, and README updates