Accounting for Consultants

Hourly billing is the easy case: invoice monthly, book revenue when billed, chase collections. The other three models are where books go wrong. Fixed-fee projects concentrate risk in your estimate, so revenue looks great until the hours run 40% over scope. Milestone billing creates months of invisible work followed by a spike, which makes an unmanaged P&L useless for spotting trends. And retainers, the best model for cash flow, are the worst for accounting discipline.

A prepaid retainer is not income yet. It is a deposit against future work, and it belongs in a deferred revenue liability account until you earn it. Book a $30,000 six-month retainer as January revenue and your January looks heroic while February through June look like a slump that never happened. Recognize $5,000 a month as delivered and the P&L tells the truth. For tax filing, a cash-basis firm generally picks up the prepayment when received; the point of the liability account is management truth, and your CPA reconciles the difference at filing time.

Most established consultancies end up with a mix. That is fine; the books just need to handle each stream by its own rules instead of dumping everything into one income line dated whenever the deposit cleared.

The default chart of accounts in any accounting app treats a consulting firm like a lemonade stand: one income account, a pile of expense categories. The upgrade that changes decisions is structural, not cosmetic. Split revenue by type (hourly, fixed fee, retainer), create a direct-cost section for subcontractors and project expenses that sits above the overhead lines, and, most importantly, tag every revenue and direct-cost transaction to a client or project using classes, tags, or projects in your software.

With that structure, gross margin per client falls out of the system automatically: what the client paid, minus the subcontractors and direct costs that served them. Without it, the firm's biggest client and its least profitable client can be the same client for years without anyone noticing, because the P&L only ever shows the blended average.

Utilization is billable hours divided by available hours. A solo consultant with 2,000 working hours who bills 1,200 of them runs at 60%, which is strong; much of the rest goes to selling, admin, and delivery overhead that never hits an invoice. Effective hourly rate is collected revenue divided by total hours worked, billable or not. Those two numbers, tracked monthly, explain almost every consulting income statement.

The diagnostic power comes from watching which number moves. Revenue down with utilization steady means a pricing or collections problem. Revenue steady with utilization climbing means you are buying revenue with unpaid hours, usually scope creep on fixed-fee work. Effective rate sliding while the card rate holds means discounting, write-offs, or too much unbillable time. Your books already contain the raw material for this; the monthly close just has to surface it.

Subcontractors are how consulting firms scale past the owner's calendar, and they are also the most common compliance gap we find in consultant books. The workflow is short: collect a signed Form W-9 before the first payment, pay through a traceable method tied to an invoice, tag the cost to the project it served, and issue Form 1099-NEC in January. For payments made in 2026, the federal 1099-NEC threshold is $2,000 per payee for the year, up from the old $600 rule, though some states still require reporting at lower amounts.

Classification is the bigger exposure. The IRS looks at behavioral control, financial control, and the nature of the relationship. A subcontractor who sets their own methods, uses their own tools, carries their own clients, and invoices you by deliverable is a contractor. A "subcontractor" who works your hours, on your systems, for you alone, indefinitely, looks like an employee, and reclassification means back payroll taxes, penalties, and interest.

Run your own numbers in the S corp savings calculator. The deeper strategy work, entity timing, retirement stacking, and the QBI thresholds, lives on our tax planning for consultants page.

A big engagement lands mid-year.

A single contract that doubles your income also doubles your next estimated payment and can push you through the QBI phase-out. Recompute estimates the month it signs, not next April.

Profit clears six figures for a second year.

That is the S corp conversation, plus a solo 401(k): up to $24,500 of employee deferral for 2026 and total contributions up to $72,000 with employer profit sharing.

You hire your first subcontractor or first employee.

Classification review, payroll setup if needed, and the 1099 workflow from section four. The cost of doing this right at hire number one is trivial; retrofitting it during an audit is not.

You start selling to clients in other states.

Remote services can create state income tax filing obligations depending on each state's sourcing rules. Multi-state consulting income is a facts-and-circumstances area; flag it early.

None of these require new software; they require books structured the way sections one and two describe, and a monthly close that actually happens. The ranges are typical for boutique firms, not laws of nature; the trend line matters more than the level.

A monthly package worth paying for includes: a reconciled P&L and balance sheet, revenue split by billing model, gross margin by client or project, the six KPIs above, a deferred revenue schedule for retainers, an aged receivables report with follow-up flags, and a running year-end profit projection tied to your estimated tax plan. If your current bookkeeper sends a bank-feed P&L and nothing else, you are buying data entry, not accounting.

That is the package our outsourced bookkeeping service builds for client-service firms, with CPA review layered on top. Not sure how much of it you need? An accounting consultation scopes it in one conversation, and the broader planning picture for owner-operated firms is on the small business tax planning page.