The hours you spend doing tasks for a specific project are referred to as billable hours. On the other hand, you'll mark non-billable hours anytime you're doing duties that are critical to the overall success of your firm, such as bookkeeping or prospecting for new clients. Tracking billable hours is essential for more than just creating client invoices. It's also crucial for determining the efficiency and profitability of projects, clients, and the entire company. As a result, critical performance measures like time utilization, actual billable rate, and actual margin rate are all directly influenced by the number of billables and non-billable hours recorded.