Most firms pay for one financial role while needing another. A precise breakdown of what each one does, what each costs, and how to diagnose which your firm is actually missing.
Harold Rosbottom · Founder & Managing Partner · 8 min read
A bookkeeper records what already happened. A controller makes sure those records are accurate, controlled, and closed on schedule. A CFO uses the resulting numbers to decide what to do next — how to price, staff, borrow, compensate, and grow. The three roles are sequential rather than interchangeable, and the most common financial mistake in a growing law firm is paying for one while needing another.
The confusion is understandable. All three appear in the same conversation, all three involve QuickBooks, and firms shopping for financial help are usually shopping in the middle of a problem. So they hire whoever is available, and eighteen months later they still can’t answer a simple question: which practice areas make money?
The three roles, precisely
Bookkeeper — recording
A bookkeeper enters transactions, reconciles bank and trust accounts, processes accounts payable, runs payroll entries, and keeps the general ledger current. In a law firm, the trust accounting piece carries real weight: three-way reconciliation of IOLTA against client ledgers and the bank statement isn’t optional, and getting it wrong is a bar complaint rather than an accounting error.
Bookkeepers are backward-looking by design. The work is accuracy and completeness of the historical record.
Typical cost
$45,000 to $70,000 for an in-house full-charge bookkeeper, or $800 to $3,000 monthly outsourced.
Controller — verifying and closing
A controller owns the integrity of the financial system. Practically, that means designing the chart of accounts so it produces useful segmentation, closing the month on a defined calendar, building internal controls so no single person can both authorize and disburse, managing the audit or review process, and producing financial statements someone can rely on.
The distinction from bookkeeping is authority and design. A bookkeeper enters a case cost into whatever account she was told to use. A controller decides that case costs should be tracked by practice area, case type, and referral source, and configures the system so that happens automatically.
Typical cost
$95,000 to $150,000 in-house, or $2,500 to $6,000 monthly outsourced.
CFO — deciding
A CFO takes accurate statements and turns them into decisions. In law firms, that means:
Profitability analysis by practice area, case type, attorney, and referral source. Not revenue — true profit per case with labor, case costs, marketing, and overhead allocated.
Forecasting, including the 13-week rolling cash flow that matters enormously to contingency firms and the annual plan tied to capacity.
Capital structure — whether to fund case costs with a line of credit, a specialty lender, or retained earnings, and what each actually costs.
Compensation design — partner distributions, attorney bonus structures, and staff incentive plans that reward the behavior the firm wants.
Pricing and case selection — which case types to accept, decline, or refer out based on expected value net of cost to produce.
Transaction readiness — clean financials, normalized earnings, and defensible add-backs, whether the firm is buying, selling, or borrowing.
Typical cost
$200,000 to $350,000 base full-time; $3,500 to $12,000 monthly fractional.
Side-by-side
BookkeeperControllerFractional CFO
Time orientationPastPast, verifiedFuture
Core outputAccurate ledgerReliable statementsDecisions and forecasts
Trust accountingExecutesOwns complianceOversees risk
Reports toController or ownerCFO or ownerOwner / partners
Fixes“Our books are behind”“Our numbers don’t tie out”“We don’t know if this is profitable”
Typical firm sizeAny$3M+$3M–$5M+
Annual cost$45K–$70K$95K–$150K$42K–$144K fractional
Diagnosing which one you need
Answer these honestly.
Are your financial statements closed within 15 business days of month end, every month? If no, you have a bookkeeping or controller problem. Nothing else can be fixed until this is.
Do you trust the numbers when you see them? If your instinct on receiving a P&L is to question it rather than act on it, that’s a controller problem — the system isn’t producing reliable output.
Can you state your net profit margin for last month without looking it up? If not, you have a reporting cadence problem, which is a controller issue with CFO implications.
Do you know which practice area or case type is most profitable, with allocated costs? If no, that’s squarely CFO work. Most firms know their revenue mix and assume it maps to profit. It frequently doesn’t. Volume practice areas with heavy case costs and long cycles can carry high revenue and thin or negative contribution.
Do you know your cost per signed case by marketing channel? Also CFO territory, and it usually requires cooperation between finance and marketing that nobody currently owns. We cover the method in cost per signed case.
Have you made a capital decision in the last year without a model? Signing a lease, hiring three attorneys, taking a line of credit, buying a firm — if these were decided on gut feel, that’s what a CFO prevents.
The pattern: bookkeeping and controller problems are about the past being unclear. CFO problems are about the future being unmodeled.
The order matters
If your books are a mess, do not hire a fractional CFO. This is the single most expensive sequencing error in law firm finance. A CFO working from unreliable data produces analysis that is precise, confident, and wrong — and then the firm makes a real decision based on it. Fix the foundation first. Any competent fractional CFO will tell you this in the first meeting and will often insist on a cleanup phase before doing anything else.
Conversely, if your controller has closed the books cleanly for eighteen straight months and nobody reads them, adding more accounting rigor won’t help. The bottleneck has moved.
Firms between $3M and $15M in revenue frequently run a stack: outsourced bookkeeper, part-time or outsourced controller, fractional CFO 10 to 20 hours a month. Combined cost lands somewhere around $85,000 to $160,000 annually — meaningfully less than a single full-time CFO, and it covers all three functions rather than leaving two of them to the founder at midnight.
Why a tax CPA isn’t a substitute
Nearly every firm has a CPA. Nearly every firm assumes that covers finance. It doesn’t, and the reason is structural rather than a criticism of CPAs.
A tax CPA is engaged to minimize tax liability on a completed year. The work is retrospective, deadline-driven, and compliance-oriented. Excellent tax planning is genuinely valuable and can save a firm six figures. But your CPA is not building your 13-week cash forecast, not modeling whether the third associate pays for herself, not analyzing whether your mass tort docket is generating positive contribution net of case cost carry, and not designing your partner compensation formula. Those aren’t tax questions.
The two roles complement each other. In well-run firms they talk regularly — the CFO builds the plan, the CPA optimizes its tax consequences.
What to expect in the first 90 days
A fractional CFO engagement typically opens with a financial diagnostic: reconstructing 24 months of financials into a usable format, segmenting revenue and cost by practice area and case type, and rebuilding the chart of accounts if it can’t support that segmentation. Most firms discover something uncomfortable here — a practice area losing money, a marketing channel with negative unit economics, or an owner compensation structure that has quietly made the firm unfinanceable.
From there: a rolling cash forecast, a monthly financial package that fits on two pages and gets reviewed in a scheduled meeting, and a model for the two or three biggest pending decisions. The output isn’t a report. It’s a recurring rhythm where the firm’s leadership actually uses its numbers.