Tenth-hour billing: why 6-minute increments are fairer and pay more

Most consultants skip billing anything under ten minutes because a quarter-hour feels like overcharging. Tenths fix both problems: the client pays for 6 minutes, and you stop giving the small work away.

What tenth-hour billing is

You bill time in units of 0.1 hour — 6 minutes — rounding each piece of work up to the next tenth. A 5-minute call is 0.1 h. A 20-minute review is 0.4 h. Lawyers and accountants have billed this way for decades because it is precise enough to be fair and simple enough to total.

Why it’s fairer to your clients

Task	Billed in tenths	Billed in quarter hours
5-minute call	0.1 h	0.25 h
8-minute email reply	0.2 h	0.25 h
20-minute review	0.4 h	0.5 h
50-minute session	0.9 h	1.0 h

Rounding to a quarter or half hour charges clients for time you didn’t spend. Tenths keep the rounding to a few minutes, so every line on the invoice is easy to defend.

Why it pays you more anyway

The real loss isn’t rounding — it’s the work you never log. When billing a quick call means charging 15 minutes, most people feel awkward and skip it. Those tasks add up:

Skipped quick tasks	Hours a month (21 workdays)	At $150/h	At $200/h
2 a day	4.2 h	$630	$840
4 a day	8.4 h	$1,260	$1,680
6 a day	12.6 h	$1,890	$2,520

Billing a 0.1 h line for a 5-minute task feels reasonable to you and to the client, so it actually gets logged.

Minutes to tenths

Minutes	Bill	Minutes	Bill
1–6	0.1	31–36	0.6
7–12	0.2	37–42	0.7
13–18	0.3	43–48	0.8
19–24	0.4	49–54	0.9
25–30	0.5	55–60	1.0

How to tell clients

Put one sentence in your agreement: “Time is billed in tenths of an hour (6-minute increments), rounded up per task.” Then make the invoice show it — a date, a short description and a 0.1–0.3 h line reads as careful, not nickel-and-diming.

Make small entries effortless

The habit only sticks if logging takes seconds: one-tap 0.1, 0.2 and 0.3 h buttons, dictation for the description, and a timer that rounds to the tenth when you stop it.