Day.js vs Luxon
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
Open source · MIT
A small JavaScript library for working with dates and times, with an API similar to Moment.js.
Open source · MIT
A JavaScript library for working with dates, times, and time zones.
The short answer
Choose Day.js if you need…
- JavaScript developers who used Moment.js and want a smaller library
- Front-end projects where bundle size matters
- Apps that need date formatting and simple date arithmetic
- Projects that need localized date output via locale files
Choose Luxon if you need…
- JavaScript developers who need to work with dates and time zones in an app
- Teams moving away from Moment.js, since the README has a guide for Moment users
- Projects that want to avoid shipping large locale or time zone data files
Side-by-side
| Day.js | Luxon | |
|---|---|---|
| Type | Library | Library |
| Price | Free and open source | Free and open source |
| Licence | MIT | MIT |
| GitHub stars | 48.7k | 16.5k |
| Setup difficulty | Beginner | Beginner |
| How you get it | Install with a package manager | Install with a package manager |
| Main language | JavaScript | JavaScript |
| Last code update | 52 days ago | 3 months ago |
What each one is
Day.js
Day.js is a small JavaScript library (about 2kB, per the README) that parses, checks, changes, and formats dates and times. Its API is largely compatible with Moment.js, so people familiar with Moment.js can use it with little relearning. Its objects are immutable, so operations return new values instead of changing the original.
Luxon
Luxon is a JavaScript library for handling dates and times. It provides DateTime, Duration, and Interval types, and uses the browser or runtime's built-in Intl and time zone support rather than bundling its own locale or time zone data. Developers use it to parse, format, and do math on dates in a chainable, immutable way.
Best for
Day.js
- JavaScript developers who used Moment.js and want a smaller library
- Front-end projects where bundle size matters
- Apps that need date formatting and simple date arithmetic
- Projects that need localized date output via locale files
Luxon
- JavaScript developers who need to work with dates and time zones in an app
- Teams moving away from Moment.js, since the README has a guide for Moment users
- Projects that want to avoid shipping large locale or time zone data files
Strengths
Day.js
- Small footprint (about 2kB according to the README)
- Familiar API for anyone who has used Moment.js
- Immutable and chainable, which makes code easier to reason about
Luxon
- Immutable, chainable API that the README describes as unambiguous
- Uses native time zone and Intl support, so no separate locale or time zone files are needed
- MIT licensed with a large star count and documented API and upgrade guide
Not ideal for
Day.js
- Projects that need full timezone handling beyond what the README describes; the README does not detail timezone support, so check the docs first
- Non-JavaScript environments, since the library is written for JavaScript
- Users who need a graphical or no-code tool
Luxon
- Non-developers, since it is a code library and needs to be called from a program
- Projects that cannot rely on the platform's Intl and time zone support, since Luxon uses it rather than bundling its own data
- Anyone who only needs a simple date display and not a library dependency
Trade-offs
Day.js
- Some functionality is in optional plugins, which must be loaded separately
- Compatibility with Moment.js is described as largely, not complete, so some code may need changes
- Documentation and details live on the external site day.js.org rather than the README
Luxon
- Depends on the runtime's Intl and time zone support, so behavior can vary across environments (inferred from the feature description)
- The README does not list a latest release, and the project mentions planning a major version 4.0, so check the current status before adopting
- The README is brief; detailed usage is on the external documentation site
Getting started
Luxon
Install from npm (package name from npm badge link)
npm install luxonFrequently asked questions
What is the difference between Day.js and Luxon?
Day.js: A small JavaScript library for working with dates and times, with an API similar to Moment.js. Luxon: A JavaScript library for working with dates, times, and time zones. Day.js suits javascript developers who used moment.js and want a smaller library, while Luxon suits javascript developers who need to work with dates and time zones in an app.
Are Day.js and Luxon free?
Day.js: Free and open source. Luxon: Free and open source.
Is Day.js or Luxon more popular?
Day.js has more GitHub stars (48.7k) than Luxon (16.5k). Popularity isn't the same as fit — check which one matches your use case above.
What are other alternatives to Day.js and Luxon?
Other options people compare them with include flatpickr, react-dates.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.