To track billable hours, record each task as you do it in six-minute increments, tag it to the right client or matter, and write a description specific enough that someone reading the invoice knows exactly what you did. That’s the whole system in one sentence. The habits around it — what to count, how to describe it, what never to bill twice — are what separate time records that get paid from records that get cut during review or trigger an ethics complaint.
What Counts as Billable
Billable time is work that directly advances a specific client’s objectives and can be charged under your engagement agreement. Legal research, drafting, negotiation, deposition prep, and client communication about the matter all qualify. In consulting or accounting, the same logic applies to analysis, strategy sessions, and client deliverables. The test is simple: someone asked for the work, and the agreement says they pay for it.
Everything else is non-billable. Internal meetings, administrative work, training, continuing education, business development, and firm communications keep the business running but belong to overhead. Blurring the line creates ethical problems and damages client trust, so draw it clearly before you start recording anything.
Travel sits in between. If a client meeting or court appearance requires travel that keeps you from serving other clients, billing for it is generally reasonable, and many professionals bill distant travel at half their normal rate. Local travel inside your home market usually isn’t billed unless you’re doing substantive work during the trip, like a strategy call. Whatever your policy, put it in the engagement letter so the invoice doesn’t surprise anyone.
The Six-Minute Increment
The standard unit of billable time in professional services is one-tenth of an hour, or six minutes. An hour divides into ten segments: a six-minute call is 0.1, a twelve-minute document review is 0.2, and so on up to 1.0 for a full hour. Any task under six minutes rounds up to 0.1. The decimal keeps the math clean when you multiply time by your hourly rate.
Some firms use fifteen-minute increments and record any partial quarter-hour as 0.25. That approach can work for long tasks but inflates short ones badly. Four one-minute calls on four different matters would generate a full hour of billable time for less than five minutes of actual work. The ABA has flagged this, noting that minimum time increments can lead to inflated and unreasonable fees, and courts have treated quarter-hour billing as inherently suspect when short tasks are involved.1American Bar Association. ABA Formal Opinion 93-379 – Billing for Professional Fees, Disbursements and Other Expenses Six-minute increments are the safer default.
Record Time as You Go
The single most important habit in billable-hour work is recording time while you’re doing the work, not reconstructing it later. End-of-day reconstruction is where most revenue leaks start. People underestimate how long tasks took, forget short calls entirely, and lose track of which matter consumed which block of time. Contemporaneous recording fixes all of it.
The simplest tool is a running timer. Most legal and professional billing platforms have one built in: start it when you begin a task, stop it when you finish, and the software captures the duration and attaches it to a matter. If you don’t have dedicated software, a spreadsheet with columns for date, client or matter number, task description, start time, and end time works, though it demands more discipline and introduces transfer errors when the data moves into an invoice.
Whichever tool you use, every entry needs the same handful of fields: the date, a client or matter identifier, the time in decimal format, and a narrative description. The identifier prevents cross-matter billing errors when you’re juggling several clients in a day. The narrative justifies the charge when the client reviews the invoice.
Writing Descriptions That Survive Review
Vague entries are the fastest way to get an invoice rejected or written down. “Worked on case” or “research” tells a client nothing. A description needs to identify the specific task. “Reviewed plaintiff’s responses to first set of interrogatories and identified inconsistencies in damage calculations” gives the client enough context to understand what they paid for. In consulting, “Analyzed Q3 revenue data and drafted preliminary findings for board presentation” does the same work.
The other common mistake is block billing: lumping multiple tasks into one entry. A line reading “Prepare for and attend deposition; review exhibits; draft follow-up letter — 4.5 hours” makes it impossible for the client or a reviewing court to judge whether that time was reasonable for each piece. Corporate legal departments increasingly use automated review software that flags block-billed entries and rejects them outright. Courts reviewing fee petitions have applied across-the-board reductions of 10% or more when attorneys submit block-billed records.
The fix is one task per entry. If you spent 1.2 hours preparing for a deposition and 3.0 hours attending it, those are two separate lines. Recording them takes slightly more effort and dramatically reduces pushback on the bill.
Ethical Lines Your Tracking Has to Respect
For attorneys, how you track hours is governed by professional conduct rules, not just firm preference. ABA Model Rule 1.5 prohibits charging an unreasonable fee and lists eight factors for assessing reasonableness, including the time and labor required, the difficulty of the work, the customary rate in your area, and the results obtained. The rule also requires that the basis or rate of the fee be communicated to the client, preferably in writing, before or within a reasonable time after representation begins.2American Bar Association. Model Rules of Professional Conduct – Rule 1.5 Fees Poor tracking can trigger ethical complaints and discipline.3American Bar Association. Billing Best Practices for New Lawyers
Don’t Bill the Same Time Twice
ABA Formal Opinion 93-379 spells it out: a lawyer who spends four hours working on matters for three different clients has not earned twelve billable hours. If you fly six hours for one client and work on another client’s file during the flight, you cannot bill both clients for the full flight. The opinion also addresses recycled work product. If you drafted a memo for Client A last year and reuse it for Client B with minor changes, you cannot bill Client B for the full original drafting time. The benefit of that efficiency belongs to the client.1American Bar Association. ABA Formal Opinion 93-379 – Billing for Professional Fees, Disbursements and Other Expenses A tracking habit of logging two concurrent entries for the same block of time will catch you here.
Don’t Pad
Rule 1.5 and its state equivalents also prohibit billing more time than you actually worked.3American Bar Association. Billing Best Practices for New Lawyers Inflating hours, aggressive rounding, or logging time you spent staring at the ceiling while nominally “reviewing” a file are all padding. These aren’t close calls about whether a task took six minutes or twelve; they’re fabrications, and they’re treated as such. Disciplinary proceedings, malpractice suits, and termination of the client relationship are all on the table.
Retainers and the Trust Account Boundary
Tracking a billable hour doesn’t make the money yours. Many attorney-client relationships start with a retainer paid up front, and under ABA Model Rule 1.15 that money must sit in a client trust account separate from the firm’s operating funds.4American Bar Association. Model Rules of Professional Conduct – Rule 1.15 Safekeeping Property The funds belong to the client until the lawyer earns them. As work is performed, the lawyer sends an itemized invoice and then transfers the corresponding amount from the trust account to operating.
Commingling client trust funds with your own operating money is one of the most heavily disciplined ethical violations in law. It can produce suspension or disbarment even if no client funds are actually lost. Lawyers may deposit a small amount of their own money into the trust account solely to cover bank service charges, and that’s the only permitted exception.4American Bar Association. Model Rules of Professional Conduct – Rule 1.15 Safekeeping Property Until the work is done and properly billed, retainer money is off-limits. Even borrowing from it briefly with every intention of paying it back can trigger discipline.
Check Whether Your Tracking Is Actually Working
Two numbers tell you whether your tracking habits are turning into revenue.
Your utilization rate is the percentage of your available work hours spent on billable tasks. Work an eight-hour day and bill 3.2 hours, and your utilization is 40%. The average across the legal profession hovers around 37%, meaning most lawyers spend nearly two-thirds of the workday on non-billable activity. Watching this number tells you where time is being lost to administrative overhead.
Your realization rate measures how much of the time you bill actually gets paid. Bill $100,000 in a quarter and collect $85,000 after write-downs, disputes, and uncollected invoices, and realization is 85%. This is the number that separates busy practices from profitable ones. High utilization means nothing if half the bills get cut during pre-bill review or go unpaid. Tracking both together gives you a realistic picture of what your time records are actually worth.