Billing Rates
Estimated Weekly Hours
Common threshold: 15% to 25% of original retainer
Enter the retainer balance, billing rates, and estimated weekly hours to project when the retainer will be depleted and when to request replenishment.
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Introduction
A depleted retainer that stops an attorney's work mid-matter is one of the most avoidable disruptions in legal practice -- and one of the most common. The Clio Legal Trends Report found that cash flow problems, often driven by retainer management failures, are among the top operational stressors reported by small and mid-size law firms. The problem is not that clients refuse to replenish retainers. It is that firms wait until the balance hits zero to ask, leaving a payment processing gap of 7 to 14 days during which work must either stop or be done without secured funding. The solution is a replenishment trigger at 20% to 25% of the original retainer -- calculated from actual weekly billing pace, not from intuition. This calculator models the burn rate, depletion date, and optimal replenishment trigger for every active retainer in the firm.
What This Calculator Does
This retainer depletion calculator tracks hourly billing against a client retainer balance and projects the depletion date and optimal replenishment request date. It calculates weekly burn rate from multiple timekeepers at blended rates, generates a week-by-week drawdown schedule, and flags the replenishment alert date based on a configurable threshold percentage of the original retainer amount.
The Formula
The weekly burn rate is calculated by multiplying each timekeeper's hourly billing rate by their estimated weekly hours on the matter. Multiple timekeepers (partner, associate, paralegal) are each calculated separately and summed. The current retainer balance divided by the weekly burn gives weeks remaining until depletion. The replenishment alert is triggered when the balance is projected to fall to the threshold amount -- typically 15% to 25% of the original retainer -- giving the firm time to invoice and receive payment before funds run out.
Step-by-Step Example
Enter retainer balance and timekeeper details
Retainer balance: $15,000. Partner: $400/hr, 2 hours/week. Associate: $240/hr, 4 hours/week. Paralegal: $130/hr, 3 hours/week.
Calculate weekly burn rate
Partner: $800/week. Associate: $960/week. Paralegal: $390/week. Total weekly burn: $2,150.
Project depletion timeline
Weeks until depleted: $15,000 / $2,150 = 6.98 weeks (approximately 7 weeks). Blended hourly rate: $2,150 / 9 hours = $238.89/hr.
Set replenishment alert
Threshold: 20% of original $15,000 = $3,000. Alert triggers when balance drops to $3,000. Weeks until alert: ($15,000 - $3,000) / $2,150 = 5.58 weeks. Send replenishment invoice at week 5. Allow 10 days for client to process payment before balance reaches zero.
Real-World Use Cases
Corporate Litigation Retainer Tracking
A 5-timekeeper team on a complex commercial dispute burns through a $50,000 retainer in 8 to 10 weeks during active discovery. Running the projection weekly allows the partner to request a $30,000 replenishment at week 6, receive it by week 7.5, and maintain uninterrupted workflow through a critical deposition period.
Family Law Monthly Retainer Model
A family law attorney managing a contested divorce sets a $5,000 monthly retainer for ongoing representation. The calculator shows that at 12 billable hours per month at $275/hr, the $3,300 monthly burn leaves a $1,700 surplus that accrues until trial preparation intensifies. Modeling this in advance helps the attorney set the retainer at the right level for peak periods.
Client Budget Transparency Reporting
A corporate client requires monthly budget-versus-actual reporting on outside counsel costs. The retainer burn projection is included in the monthly status report: retainer balance, weekly burn rate, projected depletion date, and the recommended replenishment amount. This transparency reduces client billing disputes and demonstrates professional financial management.
Comparison
| Retainer Size | Typical Practice Area | Avg Weekly Burn | Typical Duration | Replenishment Trigger |
|---|---|---|---|---|
| $2,500-$5,000 | Simple family law, traffic, basic contracts | $500-$800/week | 4-8 weeks | At $750-$1,000 remaining |
| $5,000-$15,000 | Contested family law, employment, real estate disputes | $800-$2,000/week | 4-12 weeks | At $1,500-$3,000 remaining |
| $15,000-$50,000 | Commercial litigation, criminal defense, IP disputes | $2,000-$6,000/week | 8-20 weeks | At $4,000-$10,000 remaining |
| $50,000+ | Complex litigation, M&A, regulatory matters | $5,000-$20,000+/week | Ongoing | At 20-25% of balance |
Common Mistakes to Avoid
Waiting until the retainer balance hits zero to request replenishment. Payment processing, client approval cycles, and wire transfer timing mean a 7 to 14 day gap between invoice and receipt is standard. Work that must stop during this gap damages the client relationship and disrupts case momentum. Request replenishment at 20% to 25% remaining.
Using average weekly hours without accounting for matter intensity peaks. Discovery deadlines, deposition weeks, and motion briefing periods can triple or quadruple normal billing. Build in a surge multiplier for known intensive periods when projecting depletion timelines.
Tracking only attorney hours and forgetting paralegals and law clerks. A matter with a $400/hr attorney billing 2 hours per week and a $130/hr paralegal billing 6 hours per week has a burn of $1,580 per week -- 33% more than the attorney hours alone would suggest.
Not including the replenishment threshold clause in the engagement letter. The obligation to replenish should be written into the fee agreement, specifying the threshold amount, the timeframe for payment after notice (typically 5 to 10 business days), and the firm's right to stop work if replenishment is not received.
Frequently Asked Questions
Accuracy and Disclaimer
Retainer depletion projections are estimates based on the billing rates and weekly hours entered. Actual burn rates fluctuate as matter activity intensifies or decreases. Projections should be updated monthly or when significant matter developments change the expected pace of work. Attorneys must comply with all applicable state bar ethics rules regarding client trust accounts, retainer agreements, and fee arrangements. Consult your state bar association for jurisdiction-specific requirements.
Conclusion
Proactive retainer management keeps cash flow predictable and client relationships professional. Once you have the burn rate modeled, use our Legal Matter Budget Calculator to build a phase-by-phase cost projection for the full matter, and check the Billable Hour Calculator to ensure your weekly billing pace across all clients is sufficient to hit annual revenue targets.
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