I would fill a like container with fabric, measure it to determine the yardage and multiply by $8 (average price for a yard of cotton fabric). Then multiply by the number of containers you had and up it by 10 to 15 percent, just in case you missed something. That should satisfy the insurance company. So sorry this happened to you. It must be heart wrenching to lose your stash and so much stash. That is a lot of fabric!