The biggest reason to track income and expenses by project is knowing which engagements actually make you money. A $15,000 contract sounds great until you realize you spent $4,000 on subcontractors, $1,200 on software licenses, and 120 hours of your own time. Without project-level tracking, you only see total revenue and total expenses for the month. You never learn which clients are profitable and which ones are quietly draining your margins.

In QuickBooks Online, the Projects feature lets you create a project for each client engagement and assign transactions directly to it. Every invoice you send and every expense you incur for that project gets tagged. When you pull up the project view, you see total income, total costs, and net profit in one place. This is the foundation, and it only works if you’re consistent about assigning transactions as they happen.

For income, tie every invoice to the correct project when you create it. If you have retainer clients, create a recurring project or a new one each quarter depending on how you want to measure. The goal is making sure no revenue sits in your books unattached to a specific engagement.

For expenses, separate direct project costs from general overhead. Direct costs include things like subcontractor payments, project-specific software, travel to client sites, and any materials purchased for a particular engagement. These get assigned to the project. Overhead like your internet bill, general liability insurance, or accounting fees are business expenses that don’t belong to any single project. Trying to split overhead across projects creates busywork without adding useful insight.

Time tracking is where many consultants fall short. Even if you bill flat fees instead of hourly rates, tracking your hours per project lets you calculate your effective hourly rate. You might discover that your $8,000 project took 90 hours (about $89 per hour) while your $5,000 project took 25 hours ($200 per hour). That information changes how you price and which types of work you pursue.

Review project profitability monthly or at the end of each engagement. Look at what you earned versus what you spent, including your time. If a project type consistently underperforms, raise your rates or stop taking that kind of work. If certain clients require more revisions, more meetings, or more scope changes, your project data will show it clearly.

Keeping this system running smoothly takes discipline, and that’s where working with a small business bookkeeping service helps. A bookkeeper can make sure every transaction lands in the right project, reconcile your accounts regularly, and generate the reports you need to see how each engagement performed. That way you spend your time on client work instead of sorting through transactions at the end of the month.