The default sizes sent by Shiptheory to Fedex are 25cm x 25cm x 25cm.
You can change the sizes passed Fedex your standard shipping dimensions by navigating to your Fedex Settings in Shiptheory.
At the bottom of the Fedex settings page in Shiptheory you'll find a small cog (the advanced options).
Here you can specify the dimensions (height, width, depth) that are to be used.
If you have any questions please contact us