How much billable time is lost by reconstructing the day?

A lawyer can complete a full day of client work without the full day reaching the timesheet. The loss does not usually come from forgetting a hearing or a long drafting session. It accumulates through short activities that become difficult to reconstruct hours later.

The available evidence does not support one guaranteed percentage for every firm. It does show that the loss can be large enough to affect revenue materially.

12% of billable hours may never reach the timesheet

In 2017, TIQ and Clocktimizer surveyed 31 Dutch law firms and reported that an average 12% of billable hours went unrecorded. According to Advocatie's report on the survey, the main reason was that lawyers forgot work they had completed. Existing systems made recording time during the day difficult, leaving lawyers to reproduce their activities afterwards.

The figure is directly relevant to Dutch law firms, but it should not be mistaken for an official benchmark. The survey was conducted by two timekeeping vendors, and the published coverage does not provide the questionnaire, underlying records or composition of the participating firms. It tells us what those vendors found in their sample, not what every firm will recover.

Other legal-sector guidance points in the same direction. The Association of Legal Administrators suggests that disciplined timekeeping can recapture around 5% of time that slips through the cracks. This is professional guidance rather than controlled research, but both sources indicate that the gap is material rather than theoretical.

The smallest activities disappear first

A scheduled meeting remains visible in the calendar. A document may show when it was last edited. The harder work to recover is scattered between those anchors: reading an email, returning a short call, checking a provision, researching one question or briefly switching matters.

To reconstruct that work, a lawyer searches through sent mail, calendars, call histories, documents and browser tabs. The lawyer must then estimate each duration, connect related activities and select the correct matter. When the evidence is incomplete, a cautious lawyer may omit the activity entirely. Another may estimate too generously. Neither produces a complete, precise record.

Memory becomes less reliable within hours

Academic research has not measured the percentage of legal fees lost to reconstruction, but it does explain why the problem occurs. A study of online time diaries completed by 8,535 Belgian teachers found that data quality began deteriorating within several hours of an activity.

A Management Science study of 401 managers and professionals compared retrospective reports of computer use with monitored activity. Heavy users tended to underestimate their usage, while light users overestimated it. A systematic review of self-reported task duration research similarly concluded that the size and direction of errors vary with the task.

That distinction matters. Research supports replacing memory with contemporaneous evidence. It does not justify promising that every lawyer will recover the same percentage.

Missed time can cost tens of thousands per year

Time leakage occurs before realisation and collection. If an activity never reaches the timesheet, a billing partner cannot review it, write it down or invoice it. It simply disappears from the revenue cycle.

The Advocatenblad's 2023 salary survey found that participating firms expected their lawyers to record an average of 1.226 billable hours per year. The reported targets ranged from 1.000 to 1.350 hours. Using the average target as an annual workload reference, a 5% capture gap represents approximately 61 hours. A 12% gap represents approximately 147 hours.

Knab's 2026 research reports an average advertised rate of € 241 per hour for self-employed Dutch lawyers, excluding VAT. At that rate, the estimated annual value is approximately € 14.773 at 5% leakage and € 35.456 at 12% leakage per lawyer.

This is an exposure estimate, not a revenue forecast. The annual-hours figure is a target for employed lawyers, while the published rate concerns self-employed lawyers. A firm's actual result depends on its recorded hours, rates, billing rules, write-downs and collection. The calculation is most useful when those two published inputs are replaced with the firm's own figures.

The answer for your firm is measurable

Industry figures establish that there is a problem worth investigating. A firm's own records determine its size. Establish a baseline under the current timekeeping method, then compare it with automatic capture across comparable lawyers and matters. Measure the additional time approved, the entries rejected, the editing required and the amount ultimately collected.

Sixminute observes work across applications and turns that activity into matter-specific entries with client-ready narratives. Lawyers review those entries before releasing them into the firm's existing practice-management system. The result is not an assumed recovery percentage, but a record from which the firm can calculate how much billable work reconstruction was leaving behind.