What Are Billable Hours? Increments, Retainers, and Invoices

Billable hours are the units of time your lawyer, paralegal, or legal assistant spends working on your case, tracked in small increments and multiplied by that person’s hourly rate to produce the fees on your invoice. Most firms log work in six-minute blocks, so even a short phone call generates a minimum charge. Once you understand how the increments, rates, and retainer accounting fit together, a legal bill stops looking like a wall of numbers and starts reading like a record of work you can check.

The Six-Minute Increment and the Math Behind It

Most firms divide one hour into ten equal increments of six minutes each, and every task is rounded up to the nearest increment.¹ Each increment equals 0.1 of an hour in the decimal format that appears on your bill. A four-minute phone call rounds up to 0.1 hours. A twelve-minute email exchange rounds to 0.2. A full sixty minutes is 1.0. Some firms still bill in quarter-hour (fifteen-minute) increments, though that approach is less common today.

To check what any line item cost, multiply the decimal by the hourly rate. If your lawyer charges $350 per hour and logs 0.3 hours for a task, that entry is $105. A full hour of courtroom work at the same rate is $350. Billing software does this automatically, but the arithmetic is simple enough to verify with a calculator.

What Counts as Billable Work

Billable time covers any task that directly advances your legal matter. The usual categories are:

Legal research in case law, statutes, and regulations relevant to your situation.
Drafting and revising complaints, motions, contracts, settlement agreements, and demand letters.
Phone calls, video conferences, in-person meetings, and emails about your case.
Depositions and discovery, including questioning witnesses under oath and reviewing documents produced by the other side.
Court appearances, including hearings, oral arguments, mediations, and trial proceedings.
Negotiations with opposing counsel on settlement, scheduling, or procedural issues.
Travel to court, depositions, or other case-related appointments, though some firms discount travel time or bill it at a reduced rate.

Not everyone on your matter bills at the same rate. Attorney rates generally run between roughly $200 and $500 per hour, with higher numbers in major metropolitan areas and specialized practice areas. A first-year associate charges far less than a senior partner in the same group. Paralegals and legal assistants typically bill in the $100 to $200 range and handle document review, case organization, and initial research. Because the gap between attorney and paralegal rates is substantial, you benefit when the firm pushes routine work down to the least expensive qualified person. When comparing firms, look at the blended rate across everyone who will touch your file, not just the lead attorney’s number.

What Should Not Appear on Your Bill

Plenty of work happens inside a firm that should never show up on your invoice because it doesn’t serve your specific case. Partnership meetings, staff training, recruiting, continuing legal education, marketing, business development, and networking events are overhead the firm absorbs. Purely clerical tasks such as filing, organizing physical documents, and basic data entry are treated the same way, even if an attorney happens to do them. A line item that looks like administrative work charged at attorney rates is worth questioning.

Billing ethics also forbid padding hours or charging two clients for the same block of time. If a lawyer works on your documents while flying to another client’s hearing, only one of you can be billed for those overlapping minutes.²

Costs That Sit Outside Hourly Fees

Your invoice will usually include a separate section for out-of-pocket costs the firm paid on your behalf. These are not billable hours. They are actual expenses passed through to you, and they often include:

Court filing fees for lawsuits, motions, and other documents.
Expert witness fees for specialized testimony or analysis.
Court reporter fees for transcribing deposition testimony.
Service of process fees for delivering legal documents to the other party.
Copying and courier charges for reproducing large volumes of documents or shipping materials.

These add up fast in litigation. Filing fees alone range from a few hundred to over a thousand dollars depending on the court and the type of case. Ask for an estimate of likely costs at the outset so you can budget for them separately from fees.

How Retainers Hold Your Money

Many attorneys ask for a retainer before starting work. That is an advance deposit the firm draws against as billable hours accumulate. When you pay it, the money is still yours. Under professional ethics rules, the retainer must be deposited into a separate trust account, often called an Interest on Lawyers’ Trust Account (IOLTA), and kept completely apart from the firm’s own operating funds.³ The firm can only move money from the trust account into its operating account after the work has been performed and billed.

Some firms use evergreen retainers, which require you to top up the trust balance once it drops below a set minimum. The retainer agreement should spell out the minimum balance, the deadline for replenishing, acceptable payment methods, and what happens if you miss a deposit, such as the firm pausing work. Either way, you should receive detailed invoices showing each task billed against the balance.

If your case ends before the retainer is used up, or if you fire the firm, any unearned portion has to be returned to you. Keeping money that was never earned through actual work would violate the reasonableness requirement for fees.²

Reading Your Invoice and Pushing Back

You have the right to a detailed invoice that shows each task, who performed it, how long it took, and the rate charged. A few things to watch for:

Block billing, meaning multiple tasks lumped into one time entry. A block-billed line might read “Research motion to dismiss; draft response; call opposing counsel — 3.5 hours,” which gives you no way to tell how long each piece took. Courts share the concern and routinely reduce fee awards built on block-billed entries, sometimes by as much as 50 percent, because the format makes reasonableness impossible to assess. Ask the firm to break any such entries into individual line items.
Overhead disguised as billable work, such as photocopying or scheduling charged at attorney rates.
Excessive staffing, such as multiple attorneys attending the same meeting or call with no clear reason for each to be there.
Vague descriptions like “review file” or “case analysis” that don’t say what was actually reviewed or analyzed.
Rounding patterns, where every entry comes in at the same increment regardless of task, which may suggest time wasn’t tracked contemporaneously.

If something looks off, raise it with your attorney first. Many billing disputes come from vague entries rather than intentional overcharging, and the firm can usually clarify or adjust. If a direct conversation doesn’t resolve the issue, most state bar associations run fee dispute resolution programs, typically an arbitration or mediation process where a neutral panel reviews the bill. These programs are generally inexpensive and faster than filing a lawsuit. For larger matters, some clients hire independent legal auditors to review invoices against the agreed billing guidelines.

Model Rule 1.5 requires that every legal fee be reasonable and that the basis of the fee be communicated to you, preferably in writing, before or shortly after work begins.² You should always receive an engagement letter or fee agreement spelling out the hourly rate, billing increment, estimated costs, retainer amount, and payment terms before anyone starts working.

When Hourly Isn’t the Right Structure

Hourly billing is the default, not the only option. Many firms offer alternative arrangements that give you more cost predictability.

Flat fees. You pay a single predetermined amount for a defined scope of work, such as drafting a will, handling an uncontested divorce, or forming a business entity. The price doesn’t change regardless of how many hours the work takes.
Contingency fees. The attorney collects a percentage of what you recover, typically between one-third and 40 percent, and charges nothing upfront. If you don’t win, you don’t pay attorney fees. These arrangements must be in writing and are not permitted in criminal cases or certain family law matters. They are common in personal injury, employment discrimination, and other plaintiff-side cases.²
Capped fees. The firm bills hourly but agrees to a maximum total. You pay less if the case resolves quickly, and the cap protects you from runaway costs.

Each has trade-offs. Flat fees work best for predictable, well-defined tasks. Contingency fees shift the financial risk to the attorney but cost more overall on a large recovery. Capped fees offer a middle ground but still require you to review hourly invoices. When meeting with a potential attorney, ask which structures the firm offers and why one might suit your matter better than another.

1
United States District Court Northern District of California. Billing Increment Chart – Minutes to Tenths of an Hour
2
American Bar Association. Rule 1.5 Fees
3
American Bar Association. Rule 1.15 Safekeeping Property