# Unitful @refunit converts to other length units

**URL:** https://discourse.julialang.org/t/unitful-refunit-converts-to-other-length-units/128327
**Category:** General Usage
**Tags:** question, unitful
**Created:** [April 23, 2025, 11:30am UTC](https://discourse.julialang.org/t/unitful-refunit-converts-to-other-length-units/128327 "2025-04-23T11:30:39Z")
**Posts on this page:** 2
**Page:** 1

<div class="post-metadata">

### Author: ![prittjam](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/prittjam/32/21267_2.png) [@prittjam](https://discourse.julialang.org/u/prittjam)
#### Post date: [April 23, 2025, 11:30am UTC](https://discourse.julialang.org/t/unitful-refunit-converts-to-other-length-units/128327/1 "2025-04-23T11:30:39Z")

</div>

I define a pixel as a reference unit as follows

```julia
@refunit px "px" Pixel Unitful.𝐋 true

```

However, the following happens despite not defining its size,

```julia
 uconvert(u"mm", 1u"px")
1000 mm

```

Is this expected?

---

<div class="post-metadata">

### Author: ![prittjam](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/prittjam/32/21267_2.png) [@prittjam](https://discourse.julialang.org/u/prittjam)
#### Post date: [April 24, 2025, 11:14am UTC](https://discourse.julialang.org/t/unitful-refunit-converts-to-other-length-units/128327/2 "2025-04-24T11:14:46Z")

</div>

I don’t see that I redefined px anywhere in the code. I don’t know how it makes the association to other SI units.