Harvest
Best for Invoicing billable hours by project phaseWebsite: https://www.getharvest.com/
Best for: Invoicing billable hours by project phase
Starting price: $9 per user/month (billed annually)
Free plan: Yes
Pros: Strong invoicing tied to tracked time; Budget alerts by project and task
Cons: Free plan covers 1 seat and 2 projects; Flex usage fees can add to the per-seat price
Harvest turns tracked hours into client invoices with less rework than most tools in this list. You set a budget per project or task, track time against it, and the invoice pulls the same numbers. That matters for architects, because one project often runs through concept, schematic design, design development and construction documents. Harvest lets you watch each slice separately instead of learning at the end that one phase ate the fee for the next.
The Teams plan costs $9 per user per month billed annually, and Enterprise costs $14 with timesheet approvals and profitability reporting. A free plan covers 1 seat and 2 projects. Note that Harvest now adds Flex usage fees for active projects, clients, tasks and invoicing on top of the seat price, so ask for the full renewal figure before you commit.