The definition, the formula, a worked example with the arithmetic shown, and the 2025 benchmarks. Written for CFOs, directors of finance, controllers and billing managers at firms of 50 to 500 attorneys.
Lockup is the number of days a law firm's revenue spends between work being performed and cash being banked. It combines unbilled work in progress and unpaid receivables. Calculate each as the balance divided by annual fees billed, times 365, then add them. The 2025 median for law firms is 93 days (Clio Legal Trends Report, 2025).
| What it is | The days revenue spends between the timesheet and the bank account. |
| Two components | Realization lockup (unbilled WIP) and collection lockup (unpaid AR). |
| Formula | (WIP ÷ annual fees billed) × 365, plus (AR ÷ annual fees billed) × 365. |
| 2025 median | 43 days WIP, 32 days AR, 93 days total (Clio Legal Trends Report, 2025). |
| UK comparison | 134 days, or 144 including unbilled disbursements (The Law Society, 2026). |
| Why it matters | A $100M firm carries about $274,000 in every day of lockup ($100M ÷ 365). |
Lockup is the amount of a firm's revenue tied up in unbilled and unpaid work, expressed in days. It answers one question: from the moment a lawyer does the work, how long until the firm has the money?
Two components, and they behave nothing alike. Realization lockup is work performed but not yet invoiced, your WIP, which sits inside the firm and needs nobody outside it to act. Collection lockup is work invoiced but not yet paid, your AR, which moves only when the client acts.
Total lockup is the sum, and that split is the point of the metric. A firm at 60 days of WIP and 20 of AR and a firm at 25 days of WIP and 55 of AR post almost the same total and need opposite fixes.
Three formulas. Use annual fees billed as the denominator, not total revenue, so disbursements and non-fee income do not distort the result.
| Metric | Formula |
|---|---|
| Realization lockup | (WIP balance ÷ annual fees billed) × 365 |
| Collection lockup | (AR balance ÷ annual fees billed) × 365 |
| Total lockup | Realization lockup + collection lockup |
Three practical notes. Pair a point-in-time balance with a trailing-twelve-month denominator, since WIP and AR are measured on a date while fees billed is measured over a period. Decide how you treat unbilled disbursements and hold to it: the Law Society's Financial Benchmarking Survey 2026 reports 134 days excluding them and 144 days including them, on the same firms. Run it monthly, on the same day, because lockup measured at quarter-end by a firm that pushes billing before quarter-end is a flattering number rather than a true one.
Take a hypothetical 200-attorney firm, Hale & Corrigan: annual fees billed of $100M, WIP of $14M, AR of $11M.
At 91 days the firm sits just inside the 93-day median (Clio Legal Trends Report, 2025). That reads as acceptable until you separate the halves: WIP at 51 days against a median of 43, AR at 40 days against a median of 32. Worse than median on both components, median in total, which is why the aggregate is not where decisions get made.
The daily figure prices any change: $100,000,000 ÷ 365 = $273,973 per day of lockup.
| Component | Current | Target | Days released | Cash released |
|---|---|---|---|---|
| Realization lockup | 51 days ($14.0M) | 30 days ($8.2M) | 21 | $5.78M |
| Collection lockup | 40 days ($11.0M) | 25 days ($6.8M) | 15 | $4.15M |
| Total | 91 days ($25.0M) | 55 days ($15.1M) | 36 | $9.93M |
Working: 30 × $273,973 = $8,219,178, so $14,000,000 less $8,219,178 = $5,780,822. And 25 × $273,973 = $6,849,315, so $11,000,000 less $6,849,315 = $4,150,685. Together, $9,931,507. Target figures are practitioner convention, not published benchmarks.
| Metric | 2025 median | Target |
|---|---|---|
| Realization lockup (WIP) | 43 days | Under 30 days |
| Collection lockup (AR) | 32 days | Under 25 days |
| Total lockup | 93 days | Under 60 days |
Medians: Clio Legal Trends Report, 2025. Targets are practitioner convention, not published data.
43 + 32 = 75, not 93. This is not an error in the source. Each figure is a separate median across a population of firms, and medians do not add: the firm at the median for WIP days is not the firm at the median for AR days. For any individual firm the two components sum exactly to its total, as they do for Hale & Corrigan above. Benchmark each component separately and do your own arithmetic for the total.
Clio's sample skews toward small and solo firms. A 300-attorney firm with institutional clients, outside counsel guidelines and e-billing runs a longer WIP cycle than a four-lawyer practice invoicing by email. Treat 43 / 32 / 93 as directional, not as a peer benchmark for the Am Law 200.
UK firms report higher. The Law Society's Financial Benchmarking Survey 2026 put total year-end lockup at 134 days, down from 146 in 2024, or 144 days including unbilled disbursements, down from 156 in 2024.
Days sales outstanding counts from invoice issued to cash received. Lockup counts from work performed to cash received. The difference is the WIP stage, and for law firms that is the larger half.
| DSO | Total lockup | |
|---|---|---|
| Starts counting at | Invoice issued | Work performed |
| Includes unbilled WIP | No | Yes |
| Hale & Corrigan reads | 40 days | 91 days |
| What it tells you | How fast clients pay | How fast the firm converts work to cash |
Same firm, same month, a 51-day gap, all of it work already performed that the firm has not asked to be paid for. That gap explains a familiar pattern: a firm sees a 40-day DSO, concludes collections is broadly fine, and spends the year pushing receivables while the largest and most controllable delay sits upstream, unreported. At the median, 43 of the 93 days are pre-invoice (Clio, 2025), and no receivables report will show them to you.
DSO is not a bad metric, it is a partial one. Report it as a component of lockup, not as the cash-cycle number.
Divide annual fees billed by 365. That converts a process argument into a capital argument.
| Annual fees billed | One day of lockup | Ten days released |
|---|---|---|
| $50M | $136,986 | $1.37M |
| $100M | $273,973 | $2.74M |
| $200M | $547,945 | $5.48M |
Derived: annual fees billed ÷ 365.
Ten days at a $100M firm is roughly $2.7M, and it arrives without a rate letter, a client negotiation, or the realization risk a rate increase carries. Calculate your own firm's lockup →
A firm-level number averages populations that behave nothing alike. Run the same formula at group level, using each group's own fees billed as the denominator. Here is Hale & Corrigan's $100M split four ways.
| Practice group | Fees billed | WIP | AR | Realization | Collection | Total |
|---|---|---|---|---|---|---|
| Litigation | $42M | $7.0M | $5.4M | 61 days | 47 days | 108 days |
| Corporate and M&A | $28M | $4.2M | $3.1M | 55 days | 40 days | 95 days |
| Labor and employment | $18M | $1.9M | $1.6M | 39 days | 32 days | 71 days |
| Intellectual property | $12M | $0.9M | $0.9M | 27 days | 27 days | 55 days |
| Firm | $100M | $14.0M | $11.0M | 51 days | 40 days | 91 days |
Illustrative worked example, not benchmark data.
The firm average of 91 days conceals a 53-day spread. Litigation is not a slightly worse version of the firm, it is a different business with a different problem: 61 days of WIP, which is a billing-cycle issue rather than a collections issue.
Price it. Litigation bills $42M, so one of its lockup days is $42,000,000 ÷ 365 = $115,068. Moving it from 108 days to the firm average of 91 releases 17 × $115,068 = $1.96M from one group.
Then go to partner level. Two cuts earn their keep: days in draft by billing partner, the mechanical driver of realization lockup, which most firms cannot report today; and collection lockup by relationship partner, since that is who makes the call on a 90-day invoice. Set a minimum fee threshold before ranking anyone, because small books produce noisy numbers, and segment AR by reason rather than age, because a disputed invoice, one awaiting a client's internal approval, and one nobody has looked at need three different actions and look identical on an aging report.
Lockup is an outcome, not a lever. Revenue passes through five gates between work performed and cash banked, and the largest block of days sits at the billing cycle, entirely inside the firm's control. The sequence and the fix at each gate are in how law firms get paid faster.
A rejected invoice is a lockup event rather than an administrative one, so first-pass acceptance belongs on the same report as lockup, alongside the other metrics in the law firm billing KPIs guide. Work invoiced late is also easier to discount, so a long WIP cycle shows up twice: once in days, and once in the realization rate.
Oddr is a revenue intelligence platform that sits on top of a firm's existing system of record, such as Aderant, Elite/3E, ProLaw or Orion, and runs the invoice-to-cash cycle: billing, secure invoice delivery and tracking, predictive collections, client payments, and 12-month cash-flow forecasting. On lockup it reports both components by practice group and partner, plus days in draft and first-pass acceptance rate, which are the cuts most firms cannot produce without a manual export.
To be clear about what it is not: Oddr does not track time and does not manage cases. If your lockup problem starts at time capture, that is a different tool. Oddr is built for firms of roughly 50 to 500 attorneys and holds ISO 27001 and SOC 2 Type 2.
Calculate your own lockup by practice group in a few minutes, then see what a tracked invoice-to-cash cycle does to it.
Request a Demo →