how to change a drawableLeft icon size on a button?

Just use Google's MaterialButtons: https://material.io/develop/android/components/buttons/

app:icon
app:iconGravity
app:iconPadding
app:iconSize

update:

Just use the MaterialButton it has icons property, for example:

app:icon
app:iconSize
app:iconGravity
app:iconPadding



<com.google.android.material.button.MaterialButton
    app:icon="@drawable/test"
    app:iconSize="8dp"
    app:iconGravity="end"
    app:iconPadding="8dp"/>

Wrap your resource in a drawable that defines your desired size similar to:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

  <item
      android:drawable="@drawable/icon"
      android:width="@dimen/icon_size"
      android:height="@dimen/icon_size"
      />

</layer-list >

After that, use this drawable in your android:drawableLeft tag