Billing leakage tracker.
A monthly sheet that turns WIP, invoicing, and collection numbers into one headline figure: how much cash is walking out.
A monthly tracker with the four numbers that matter — hours recorded, hours billed, revenue invoiced, revenue collected — plus the realisation, collection, and leakage math already written.
Managing partners and practice managers who want the leakage conversation grounded in actual numbers, not gut feel. Any firm using hourly, fixed-fee, or mixed billing.
Realisation drift you don't notice until bonus season. Collection creeping out from 30 to 45 days. The gap between 'recorded at rate' and 'actually collected' that nobody puts a number on.
| Month | Hrs recorded | Hrs billed | Invoiced £ | Collected £ | Realisation % | Collection % | Leakage £ | Leakage % |
|---|---|---|---|---|---|---|---|---|
| Jan 2026 | 1,620 | 1,410 | £253,800 | £240,800 | 87.0% | 94.9% | £50,800 | 17.4% |
| Feb 2026 | 1,580 | 1,440 | £259,200 | £248,400 | 91.1% | 95.8% | £35,000 | 12.3% |
| Mar 2026 | 1,670 | 1,520 | £273,600 | £264,700 | 91.0% | 96.7% | £35,900 | 12.0% |
| Next 9 months left blank — add monthly. | ||||||||
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The four monthly numbers
Pull these from your practice-management system, accounts package, or time-recording tool on the first working day of the month:
- Hours recorded— total billable time logged in the month, across all fee earners.
- Hours billed— total hours that actually went on invoices sent to clients, after any pre-bill write-downs.
- Revenue invoiced— total £ on invoices raised in the month.
- Revenue collected— total £ actually received in the bank in the month.
The three formulas
These are already in the CSV. If you're rebuilding from scratch:
- Realisation %= Hours billed ÷ Hours recorded
- Collection %= Revenue collected ÷ Revenue invoiced
- Leakage £= (Hours recorded × blended rate) − Revenue collected
- Leakage %= Leakage £ ÷ (Hours recorded × blended rate)
The monthly conversation
Once the numbers are in, the review takes 15 minutes with the managing partner or finance lead. In order:
- Is realisation trending up, flat, or down? Down > 2 points in a month is a pre-bill discipline issue.
- Is collection trending? Down means aged debt is building. Pull the debtors report before next month's review.
- Is leakage £ bigger than it was three months ago? If so, which lever — realisation or collection — is driving it?
- One fix you'll commit to before next month. Only one.
Pairs well with
Run the Billing Leakage Calculator alongside this tracker to stress-test a single month. Use the tracker for trend, the calculator for a point-in-time diagnosis.
Notes from other operators.
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