About Readonly Fields in Django Administration

Django administration tip: if you want to show a field with editable=False attribute or the results of a model method in the admin form, add the field or the method name to the readonly_fields list.

from django.contrib import admin
from .models import Post

@admin.register(Post)
class PostAdmin(admin.ModelAdmin):
    fields = ["created_at", "title", "content", "get_word_count"]
    readonly_fields = ["created_at", "get_word_count"]

    @admin.display(description="Word Count")
    def get_word_count(self, obj):
        return len(obj.content.split())