Epic typically charges developers a 5% royalty for use of its Unreal Engine on projects that exceed $1,000,000 USD gross lifetime revenue. See the Unreal® Engine End User License Agreement For Publishing for more information.

However, Meta has arranged for your Unreal Engine license to be royalty-free for the first five-million US dollars (USD $5,000,000) of revenues generated from sales related to your application in the Store.

You must obtain a license to the Unreal Engine Directly from Epic. Meta is not granting you an Unreal Engine license. You remain responsible for complying with all of the terms of your license to the Unreal Engine.

Meta is only responsible for reporting and paying royalties for sales related to your application in the Store. For clarity, you must report and pay royalties to Epic on the following in accordance with your Unreal Engine license:

a. All revenues generated outside of the Store (e.g., advertising, sales through other platforms); and b. All Net Revenues above five-million US dollars (USD $5,000,000).

You can report your royalty obligations to Epic using the Epic Royalty Report - https://epicgames.formstack.com/forms/royalty_report