Why Do Lawyers Bill in Six-Minute Increments?

New clients reading their first legal invoice tend to get stuck on the same oddity: every line ends in a decimal. The call was 0.2, the letter 0.4, and nowhere does the bill just say eighteen minutes. Lawyers stop noticing this somewhere in their first week of practice. Clients never quite do, which is why the question keeps landing in intake calls and billing FAQs. The short version is that six minutes is one tenth of an hour, and law firms bill in tenths.

The longer version is more useful, because the six-minute unit has a history, rounding has real rules, and one factor matters more than whichever increment your firm happens to pick.

Six minutes is one tenth of an hour

Start with the arithmetic, because the arithmetic is the whole appeal. An hour breaks into ten six-minute pieces, and the timesheet records each piece as 0.1, so twelve minutes is 0.2 and a full hour is 1.0. At $450 an hour, a 0.3 entry is exactly $135. No long division, no rounding argument on the client's statement, and a biller can total a page of entries in her head. Bill in raw minutes instead and every single line asks somebody to divide by sixty. That, more than anything grander, is why six-minute billing increments became the default.

Where the six-minute convention came from

Lawyers did not always bill by the hour. For much of the profession's history, fees were set by the matter or by custom. Hourly billing standardized through the middle of the twentieth century, and once you charge for time, you need a unit to record it in.

Two units competed. The quarter hour, 0.25 or fifteen minutes, is easy to picture and was common early. The tenth, six minutes, is finer. The difference shows on short tasks: a brief call rounded to a quarter hour gets billed as fifteen minutes; at the tenth, the same call is six. As clients read their bills more closely, the finer unit looked fairer, so tenths won out. They also added up easily by hand, which mattered before billing software.

How rounding actually works

Real tasks rarely land on a clean tenth, so every firm needs a rounding rule. The common one rounds up to the next tenth: a four-minute task goes in as 0.1, a seven-minute task as 0.2. Some clients and their outside counsel guidelines require rounding to the nearest tenth instead, which sends that four-minute task down to 0.1. Firms doing sensitive work follow whatever the client's guidelines specify, since those terms get enforced at bill review.

Trouble comes from minimums on short tasks. A firm that bills a flat quarter hour for any call, however brief, will see those lines questioned. A two-minute call recorded as 0.5 is the classic entry that draws a red pen at bill review, and plenty of client guidelines now spell that out. The practical move is unglamorous: write the rounding rule into your firm's timekeeping policy and stick to it, matter after matter.

Increments other than the tenth

The tenth is the most common unit, but it is not the only one. Plenty of firms and clients bill differently. Some set 0.2 as the smallest increment. Others use quarter hours (0.25) on flat-rate or older arrangements, or fifteen-minute blocks for certain work. One firm can run different increments for different clients, since the client's guidelines set the terms.

This is worth checking before you configure any timekeeping tool. Ajax, the automatic timekeeping software we build, records in tenths by default, and a different firm-wide increment (0.2, 0.25, or fifteen minutes) is a configuration setting rather than a workaround. Task codes and billing rules can then be set per client, so a matter governed by UTBMS codes and outside counsel guidelines follows those rules while the rest of the firm bills as usual.

The part nobody talks about

Here's what gets lost in every argument about rounding. The increment only decides how to record time that reached a timesheet at all. The bigger number is the time that never got recorded.

At most hourly firms, 5 to 15% of billable work goes uncaptured: the four-minute call between meetings, the email answered from a phone, the quick review nobody timed. Round all of that however you like and it still bills zero, because it was never written down. The gap between rounding methods is a rounding error next to the gap between capturing your day and rebuilding it from memory later.

That's the problem worth solving. If your attorneys already record every tenth they work, rounding policy is a fine-tuning exercise. If they don't, and almost nobody does, the increment is nearly beside the point. This is where automatic capture of billable hours earns its keep: it records the small tasks as they happen, assigns each to the right matter, and applies your firm's increment, so the tenths on the bill match the day actually worked.

FAQ

What does 0.1 mean on a legal bill?

On a legal bill, 0.1 means six minutes, or one tenth of an hour, the standard smallest unit of billed time. To find the charge, multiply by the hourly rate: 0.1 at $400 an hour is $40.

Do all law firms use six-minute increments?

No. Most firms bill in six-minute increments, meaning tenths of an hour, but some use 0.2, quarter hours (0.25), or fifteen-minute blocks. A firm may even apply different increments to different clients, depending on each client's guidelines.

What about rounding up to the next increment?

Every firm rounds somehow, so the real question is whether your rounding rule would survive the client reading it. Minimums are the usual trouble spot, a big one on a tiny task most of all, since that's the first line a bill reviewer questions. Write the rule down in the timekeeping policy and hold to it; where a client's guidelines set different terms, those terms win on that client's matters.

Can billing increments be changed per client?

Yes. Increments and rounding rules can be set per client, usually to match that client's outside counsel guidelines. In Ajax, tenths are the default and a different increment is a firm-level configuration, with task codes and rules layered on per client.

The cleanest way to pressure-test a rounding policy is a real day of work. Book a demo and we'll run one through, small tasks and all.