Sum for Trello is a Chrome Extension developed by cmb.durand. This free extension adds a useful functionality to Trello.com, allowing users to easily calculate the total cost of cards in their Trello board. It is an adaptation of Trello Scrum, offering a simplified way to sum up the costs of cards per list.

With Sum for Trello, users can now see the total cost of cards in each list by simply looking at the sum displayed. The cost is indicated between parentheses in each card's description. Starting from version 0.0.8, the extension also supports negative costs, providing even more flexibility in tracking expenses.

This extension is a valuable tool for Trello users who want to keep track of the total cost of cards in their boards. Whether you're managing a project or planning your personal tasks, Sum for Trello makes it easy to calculate and monitor the financial aspects of your cards.