If you're looking to re-floor one of your rooms but its a little quirky in size. Check out this website. Its kinda nice. It'll calculate areas for rooms with angled corners. It also calculates areas that you don't want included in the area calculation. For instance, if you want a tile pathway that meets up with a carpeted area. Its kinda just fun to play around with too.
Quick Click Flooring Estimator Tool by FindAnyFloor.com