A job can look busy, valuable and under control right up to the moment someone asks a simple question: how much unbilled work have we actually done? This WIP reporting guide is for firms that need a defensible answer, not a hopeful estimate assembled from late timesheets and scattered project notes.
For professional services businesses, work in progress is not merely an accounting figure. It is time, expertise and cost already committed to a client before that value has been billed or recognised as revenue. When WIP is unclear, partners cannot see emerging write-offs, finance cannot forecast cash confidently, and project managers discover overruns after the margin has gone.
What WIP reporting should tell you
A useful WIP report answers more than, “What has not been invoiced?” It should show the value of work performed, the cost of delivering it, what can be billed now, and where commercial risk is building.
The exact treatment depends on your firm’s contracts and accounting policies. A solicitor managing matters on hourly rates needs a different view from an architect delivering fixed-fee design stages. An agency on a monthly retainer may have little traditional WIP, but still needs to know whether delivery effort is outrunning the fee.
At minimum, your report should let decision-makers see WIP by client, matter or project, service line, responsible manager and age. It should distinguish billable work from non-billable effort, then make the billing status obvious: ready to invoice, waiting for approval, held due to scope questions, or unlikely to recover.
That last category matters. A large WIP balance is not automatically good news. It can represent future invoices, but it can also hide delay, weak scope control and revenue that will never be collected.
The numbers behind reliable WIP reporting
WIP begins with recorded effort, but recorded effort alone is not enough. Your report needs a clear commercial model for converting activity into a value the firm can act on.
For time-billed work, the basic calculation is straightforward:
WIP value = approved unbilled hours × agreed billing rate
If a civil engineering team has completed 48 approved, unbilled hours on a client project at £145 per hour, gross WIP is £6,960. Then comes the part that separates useful reporting from a simple timesheet export: check the fee cap, agreed discounts, scope changes, disbursements, prior write-offs and whether the client will accept the work as billable.
For fixed-fee work, reported WIP often needs to reflect progress against delivery milestones rather than hours multiplied by a rate. Hours still matter because they reveal the cost and margin position. A £20,000 design package that is 60% complete may support £12,000 of earned value, but if the team has already consumed 85% of the planned effort, the project is heading for a margin problem.
A commercially useful report therefore shows both value and effort. Revenue recognition belongs to your accounting policy. Operational WIP reporting is the management view that tells you what is happening before month-end makes it official.
Gross WIP, net WIP and recoverability
Gross WIP is the total value of recorded but unbilled work. Net WIP is what remains after expected write-offs, discounts or provisions. Reporting both avoids a common management mistake: treating all recorded time as recoverable revenue.
Add a recoverability assessment to larger balances. A project owner may mark a balance as high confidence, review required or at risk. That judgement should not replace data, but it should force a conversation while there is still time to invoice, reset expectations or control further spend.
Build the report around decisions, not administration
The best WIP reporting guide is not a template with more columns. It is a repeatable decision process. Start with the questions your leaders need to answer every week or month.
Which completed work can be invoiced immediately? Which client balances are ageing without a clear reason? Which fixed-fee jobs are consuming effort too quickly? Which teams are carrying substantial unbilled time because approvals or billing preparation are slow?
Once those decisions are clear, build the report so exceptions surface first. A managing partner does not need to inspect every £200 entry. They need to see the £18,000 balance that has sat unbilled for 75 days, the project with effort at 110% of budget, and the client manager who repeatedly writes off time at invoice stage.
Most firms benefit from four views:
- A client or project-level WIP register showing unbilled value, age, billing status and owner.
- A budget-versus-actual view for fixed-fee and capped engagements.
- A recoverability view showing likely write-offs, discounts and disputed work.
- A trend view showing WIP movement, invoices raised and days to bill over time.
Keep the fields consistent. If every manager creates their own definition of “ready to bill”, the report becomes a debate about labels rather than a tool for improving cash and margin.
The weak point is usually time capture
WIP reports fail upstream. A polished spreadsheet cannot repair missing hours, vague narratives or timesheets completed from memory on Friday afternoon.
Manual timers and end-of-day entries create an obvious problem: people forget. They switch between client calls, drawings, emails, case files and internal work all day, then reconstruct activity when the details have already blurred. The result is understated WIP, delayed invoices and profitability reports based on partial evidence.
That is not an employee discipline issue. It is a flawed operating model.
Accurate WIP reporting requires time data that identifies the client context, the work type and the date the work occurred. It also needs a sensible review process. Finance should not have to chase every individual entry, but project leads must be able to review exceptions before time becomes an invoice.
This is where automated client time intelligence changes the equation. eppiq Timer recognises work patterns across the tools people actually use and allocates activity to the right client, reducing dependence on memory and manual timer habits. The aim is not more surveillance or more admin. It is a cleaner evidence base for billing and margin decisions.
Set a reporting rhythm that protects cash
Monthly WIP reporting is common, but monthly-only reporting is often too slow for firms with high volumes, short projects or tight cash flow. A weekly operational review catches stalled approval, missing time and fee-cap risks before they become a month-end scramble.
Use a light weekly process. Review new WIP, identify work ready to bill, resolve exceptions and assign actions to named owners. Then use the month-end review for valuation, provisions, revenue recognition and formal financial reporting.
Ageing rules should be explicit. For example, work unbilled after 30 days may require a billing reason; after 60 days, owner review; after 90 days, director-level attention. The thresholds will vary by sector and contract cycle, but silence is never a valid status.
Also separate operational delay from client delay. If a client has not approved a change request, that is a commercial issue. If an invoice is waiting because nobody prepared the narrative, that is an internal process failure. Both affect cash, but they require different fixes.
Common WIP reporting mistakes
The first mistake is valuing every recorded hour at the standard rate without checking recoverability. The second is excluding time that feels inconvenient to record, particularly short tasks, client emails and fragmented work. Small omissions accumulate quickly across a team.
Another frequent error is reporting WIP without the original budget or fee. A balance of £9,000 means very little until you know whether it sits within a £100,000 programme or against a £10,000 capped assignment.
Finally, do not confuse utilisation with profitability. A team can be highly utilised while working on underpriced retainers, delivering unpaid scope additions or accumulating time that will be written off. WIP reporting should expose that reality, not flatter it.
Questions firms ask about WIP reporting
How often should WIP be reviewed?
Review operational WIP weekly if client work moves quickly or invoice timing materially affects cash flow. Smaller firms with longer engagements may manage fortnightly reviews, but month-end should not be the first time anyone sees the numbers.
Should non-billable time appear in the report?
Yes, although it should be clearly separated from billable WIP. Non-billable time reveals delivery overhead, rework, internal support and scope leakage. Removing it entirely makes project profitability look better than it is.
Who owns WIP accuracy?
Everyone has a role, but ownership must be clear. Staff need to capture and classify work accurately. Project or client leads need to validate commercial context. Finance needs to maintain reporting rules and ensure billing follows through. No single function can solve it alone.
A WIP report should create productive discomfort. If it shows unbilled work rising, margins narrowing or time disappearing, that is not bad reporting. It is the business getting an early warning while there is still something practical to do about it.