Glossary
Work in progress (WIP)
Also called: WIP · unbilled time · unbilled work
In professional services, work in progress (WIP) is the value of time and expenses that have been recorded but not yet invoiced. Rising WIP means work is being done faster than it is being billed; old WIP is revenue at risk of being written off.
Last updated October 13, 2026
Measuring WIP
WIP = unbilled billable hours × their rates + unbilled billable expenses. Measure it per client and by age: anything older than one billing cycle deserves a reason. A monthly WIP review before invoicing is the simplest control a small firm can run.
Why WIP grows
The usual causes are delayed invoicing (waiting for a 'good moment'), unclear scope on fixed-fee work, hours that need client approval, and time logged without a project so it cannot be priced. Each is fixed by process, not by working harder: invoice on a schedule, track fixed-fee hours against the contract, and never leave an entry unassigned.
WIP and write-offs
A write-off is WIP you decide not to bill — usually because it is too old, over the agreed budget, or embarrassing to explain. Some write-off is normal; tracking it per client and per kind of work tells you where scoping or billing discipline is failing.
In Hoursmith
The invoice builder in Hoursmith lists a client's unbilled billable time and expenses so WIP is pulled onto an invoice in one step; invoiced entries are then locked, keeping WIP and billed work separate.