Every lock-up calculator asks for a work in progress figure, which is the one number a small firm cannot produce. It exists as unbilled hours in a system, not as a balance.
If more is stuck before the invoice goes out than after it, credit control is the wrong lever. Most firms reach for it anyway because debtors are the half they can see.
One client can account for a third of everything tied up, which is a concentration risk as well as a cash problem, and it does not show in a revenue report.
A partner on a high hourly rate rebuilding a spreadsheet costs considerably more than the same work done further down. Nobody calculates it because the time is not billed.
No signup and no email wall. Nothing you enter is sent anywhere.
Products solve the problem every professional services business has. When the problem is yours specifically, that is a build.