All hours (billable + non-billable) per week
Hours billed to clients per week
Filing fees, travel, copies, etc. for the billing period
Annual Projection
Optional. Used to calculate required billable hours.
Enter your rate and hours, then click calculate.
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Introduction
Attorneys at large firms are expected to bill 1,800 to 2,200 hours annually. Most bill far fewer. The Clio Legal Trends Report consistently finds that attorneys across firm sizes bill an average of 2.5 hours per day -- less than a third of their working day. The gap between hours worked and hours billed is not laziness. It is non-billable time: business development, administration, firm meetings, and unbilled client communication that never makes it to an invoice. For solo and small firm attorneys, this gap is often the direct cause of revenue shortfalls despite working 50 or 60 hours per week. This calculator models billable hour productivity against revenue targets so attorneys can see exactly how many hours must be billed and collected each week to hit their income goals -- and whether the math is achievable given their current practice structure.
What This Calculator Does
This billable hour calculator projects annual revenue, billable hour targets, and daily billing requirements based on hourly rate, target annual revenue, estimated billability rate, and collection rate. It works in both directions: enter a revenue goal to find required hours, or enter available hours to see projected revenue. It also calculates the break-even billing rate needed to cover salary and overhead at different billable hour assumptions.
The Formula
Annual billable hours are determined by the total working hours multiplied by the billability rate (the percentage of working time that is billable). At 2,000 working hours and a 60% billability rate, annual billable hours are 1,200. Multiplying by the hourly rate gives gross billed revenue. Applying the collection rate (typically 85% to 92%) gives the actual collected revenue. The daily billing requirement divides annual billable hours by the number of working days, showing the minimum daily hours that must be billed to meet the annual target.
Step-by-Step Example
Set the revenue target and hourly rate
Annual revenue goal: $250,000. Hourly rate: $275. Required billed hours: $250,000 / $275 = 909 hours. At 85% collection rate, must bill $294,118 to collect $250,000. Required billable hours: $294,118 / $275 = 1,070 hours.
Calculate daily billing requirement
Working days: 230 (accounting for vacation, holidays, sick days). Daily hours required: 1,070 / 230 = 4.65 hours per day. At 60% billability, this requires being at the desk for 7.75 hours per day of client-related work.
Check against billability rate
Billability rate: if 60% of the 8-hour workday is billable, that is 4.8 hours. This barely covers the 4.65 required. Any vacation, sick day, or administrative-heavy week creates a deficit that must be recovered.
Run alternate scenarios
At $300/hr: required hours drop to 980, daily requirement is 4.26 hours -- achievable at 60% billability. The $25/hr rate increase is worth 90 fewer required billable hours annually, reducing daily pressure by 24 minutes.
Real-World Use Cases
New Attorney Revenue Planning
A solo attorney leaving a firm to open a practice sets a $180,000 first-year revenue goal. The calculator shows that at $225/hr with 88% collection, they need 912 billable hours -- about 3.96 hours of billable work per day on 230 working days. This is achievable but requires immediate client development since building to that billing level from zero takes 3 to 6 months.
Rate Increase Justification
An attorney consistently billing 1,100 hours at $300/hr is generating $330,000 gross but collecting only $282,000 at 85.5%. Raising rates to $325/hr with the same hours and collection rate produces $305,000 collected -- a $23,000 increase for zero additional hours worked. The calculator makes this case clearly.
Associate Profitability Modeling
A managing partner evaluates whether adding a second associate is profitable. The associate bills at $225/hr, is expected to hit 1,600 billable hours at 90% collection, generating $324,000. Salary and overhead for the associate total $210,000. Contribution margin: $114,000 before partner supervision time. The calculator shows the hire is viable if the associate reaches 935 billed hours annually.
Comparison
| Firm Type | Typical Billable Hours | Billability Rate | Collection Rate | Effective Hourly Yield |
|---|---|---|---|---|
| Solo Practitioner | 900-1,300/yr | 50-60% | 82-88% | Lower -- more admin overhead |
| Small Firm (2-10) | 1,200-1,600/yr | 55-65% | 85-90% | Moderate -- some support staff |
| Mid-Size Firm (11-50) | 1,600-1,900/yr | 65-70% | 88-93% | Higher -- paralegal leverage |
| Large Firm (50+) | 1,800-2,200/yr | 70-75% | 90-95% | Highest -- billing infrastructure |
Common Mistakes to Avoid
Tracking billed hours rather than collected hours as the productivity metric. An attorney who bills 1,400 hours at $300/hr but has a 70% collection rate is collecting only $294,000 -- the same as an attorney billing 1,120 hours at $300/hr with a 90% collection rate. Collection rate is as important as billing rate and volume.
Not accounting for vacation, holidays, sick days, and CLE in the working days calculation. Using 260 working days (52 weeks x 5 days) overstates available time by 30 to 40 days. Use 220 to 235 working days as a realistic planning figure.
Setting billable hour targets based on large-firm benchmarks. A solo attorney is not comparable to a BigLaw associate. Solo practitioners have client development, administration, and billing responsibilities that consume 40% to 50% of their time. Target 1,000 to 1,300 billable hours for solo practice, not 1,800.
Ignoring write-downs in the collection rate calculation. Write-downs (reducing the billed amount before collecting) are not the same as write-offs (bad debt). Both reduce collected revenue. Track write-downs separately to identify which matters, clients, or billing habits are generating the most revenue leakage.
Frequently Asked Questions
Accuracy and Disclaimer
Billable hour and revenue projections are estimates based on the rates, hours, and collection assumptions entered. Actual revenue depends on client development, matter complexity, billing practices, and collection experience. Legal billing benchmarks are based on 2026 industry data from Clio Legal Trends Reports and ABA surveys. This calculator is for business planning purposes only and does not constitute legal or financial advice.
Conclusion
Billable hour targets only produce revenue if billing is converted to invoices and invoices are collected. Use our Legal Billing Rate Calculator to confirm that your hourly rate is set high enough to hit your income goals at realistic billable hour levels, and pair with the Retainer Depletion Calculator to project when each client retainer will require replenishment based on your weekly billing pace.
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