# Getting started with FlexUnits.jl

**URL:** <https://discourse.julialang.org/t/getting-started-with-flexunits-jl/139720>\
**Category:** General Usage\
**Tags:** units\
**Created:** [September 28, 2026, 1:42pm UTC](https://discourse.julialang.org/t/getting-started-with-flexunits-jl/139720 "2026-09-28T13:42:13Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Nathan\_Boyer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nathan_boyer/32/14825_2.png) [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Post date:** [September 28, 2026, 1:42pm UTC](https://discourse.julialang.org/t/getting-started-with-flexunits-jl/139720/1 "2026-09-28T13:42:13Z")

</div>

I am interested in using the FlexUnits.jl package. I have read through the documentation, but I’m not clear on the best way to deal with the `UnitRegistry`.

When loading the package, I want to …

1. load typical Imperial and Metric units (`u"psi"`)
2. set constants for my most used (`const psi = u"psi"`)
3. set my preferred unit simplifications (`set_preferred_unit(psi)`)

Where is the best place to keep this personalization code?

It seems to me the simplest for usage would my own `MyFlexUnits` package that has `@reexport using FlexUnits` and all the customizations. However, that workflow isn’t mentioned in the docs. The docs seem to want me to keep my customization code in a standalone file/module, but then where do I store it, and how do I load it?

Moreover, the docs say you can either modify the included unit registry or create your own. If I need to create my own package or file anyway, I wonder if there is much of a difference between using a bunch of modifying function calls in a row like `register_unit` versus just copy-paste-editing the default unit registry.

Workflow suggestions from people already using the package would be appreciated!