FontSize in percentage %?

I love how my application looks the same(same proportions) on all different screen sizes using Grids and %-size in Height and Width.

The only thing that is fixed, is the FontSize. Why is it not possible to use % for the FontSize?

And what are the workarounds?

I mean on bigger screens the FontSize should be bigger and on smaller screens smaller FontSize.

How can I achieve this?

The only solution currently is to wrap it in a <Viewbox></Viewbox> and define the viewbox as a percentage, it will look a little funny on the desktop preview but when i preview it on the iPhone it looks perfectly fine


<Viewbox Height="100%" Width="100%">
<Text Value="Hello" FontSize="30" Color="Black"/>

Play around with the fontsize & the percentages you need alter both to get what your looking for

See this existing thread as well:

Mention “FontSize” as a percentage of the parent element.

<StackPanel ux:Name="parentWindow" >
    <Text Value="Hello" FontSize="width(parentWindow)*0.5"" Color="Black"/>