6-minute billing chart: minutes to tenths of an hour
| Minutes worked | Tenths of an hour | Billed as |
|---|---|---|
| 1 to 6 | 0.1 | 6 minutes |
| 7 to 12 | 0.2 | 12 minutes |
| 13 to 18 | 0.3 | 18 minutes |
| 19 to 24 | 0.4 | 24 minutes |
| 25 to 30 | 0.5 | 30 minutes |
| 31 to 36 | 0.6 | 36 minutes |
| 37 to 42 | 0.7 | 42 minutes |
| 43 to 48 | 0.8 | 48 minutes |
| 49 to 54 | 0.9 | 54 minutes |
| 55 to 60 | 1.0 | 60 minutes |
6-minute billing divides an hour into ten units of 0.1 hours. This chart uses the usual round-up convention: any part of a 6-minute block counts as a whole block. A 4-minute call bills as 0.1 hours; a 20-minute call bills as 0.4. For longer entries, keep the whole hours and convert the remaining minutes: 1 hour 23 minutes becomes 1.4 hours.
Disclosure: This site's publisher makes the free time tracker with reports and invoicing listed below. The rounding details for Toggl Track, Clockify and Harvest come from each vendor's own help and pricing pages. The worked day is sample data.
What is a tenth of an hour in billing?
A tenth of an hour is 6 minutes, written as 0.1 on a timesheet or invoice. Billing in tenths means every piece of work is recorded as a whole number of these units: 0.1, 0.2, 0.3 and so on, up to 1.0 for a full hour. At an hourly rate of $250, each tenth is worth $25.
Billing in tenths is best known from law firms, and accountants and consultants use it too. It gives short calls, email replies and document reviews their own billable entries without charging a quarter hour for a two-minute email. One decimal place per line makes the bill easy to total.
Decimal hours and minutes are easy to confuse. 1.3 hours is 1 hour and 18 minutes, not 1 hour and 30 minutes. A quick way to check: multiply the decimal part by 60 to get minutes. 0.3 × 60 = 18, and 0.75 × 60 = 45. If your tracker shows hours and minutes and your invoice needs decimals, convert the leftover minutes with the chart rather than in your head.
How do 6-minute increments work for time over an hour?
Keep the whole hours and round only the remaining minutes. With rounding up, 2 hours 31 minutes becomes 2.6 hours because 31 minutes rounds to 0.6 on the chart. The alternative calculation is total minutes ÷ 6: 151 ÷ 6 = 25.17 units, rounded up to 26 units, or 2.6 hours.
| Time worked | Minutes ÷ 6 | Rounded up | Rounded to nearest |
|---|---|---|---|
| 4 minutes | 0.67 | 0.1 | 0.1 |
| 47 minutes | 7.83 | 0.8 | 0.8 |
| 1 hour 23 minutes | 13.83 | 1.4 | 1.4 |
| 1 hour 40 minutes | 16.67 | 1.7 | 1.7 |
| 2 hours 31 minutes | 25.17 | 2.6 | 2.5 |
| 5 hours 40 minutes | 56.67 | 5.7 | 5.7 |
The last row comes from a question one freelancer asked on Reddit: they wanted 5 hours 40 minutes rounded to 6 hours, and their tracker's free plan would not do it. In tenths it is 5.7 either way. Rounding to the next whole hour is a different billing rule, worth 18 minutes more on that one entry, and it needs to be in the agreement with the client rather than applied quietly.
Should you round up or to the nearest tenth?
Use the rounding direction in your engagement letter or the client's billing guidelines. If neither specifies one, agree it before billing. Rounding up is the convention the chart above uses, and it never takes time away: a 1-minute task becomes 6, and only an entry that is already a whole number of tenths stays the same. Rounding to the nearest tenth adds time to some entries and takes it from others, so over many entries of varied length it tends to come out close to the real total.
With rounding to the nearest tenth, the break points shift by 3 minutes. Anything under 3 minutes rounds to zero, which is why a firm that rounds to the nearest may also set a minimum charge of 0.1 for any task that was worth recording.
| Minutes worked | Rounded to nearest tenth |
|---|---|
| 0 to 2 | 0.0 |
| 3 to 8 | 0.1 |
| 9 to 14 | 0.2 |
| 15 to 20 | 0.3 |
| 21 to 26 | 0.4 |
| 27 to 32 | 0.5 |
| 33 to 38 | 0.6 |
| 39 to 44 | 0.7 |
| 45 to 50 | 0.8 |
| 51 to 56 | 0.9 |
| 57 to 60 | 1.0 |
This sample day uses a $250 hourly rate for one matter. It combines short calls and emails with longer drafting and research tasks:
| Task (sample) | Minutes | Rounded up | Rounded to nearest |
|---|---|---|---|
| Reply to client email | 2 | 0.1 | 0.0 |
| Call with the other side's adviser | 7 | 0.2 | 0.1 |
| Draft response letter | 43 | 0.8 | 0.7 |
| Review client's comments on the draft | 12 | 0.2 | 0.2 |
| Call with client | 19 | 0.4 | 0.3 |
| Send revised letter to client | 4 | 0.1 | 0.1 |
| Research on notice periods | 86 | 1.5 | 1.4 |
| Team meeting on next steps | 32 | 0.6 | 0.5 |
| Day total | 205 (3.42 h) | 3.9 h | 3.3 h |
| At $250 an hour | $854.17 | $975.00 | $825.00 |
Rounding up each entry turned 3 hours 25 minutes of work into 3.9 hours, about 29 minutes more, or $120.83 on the day. Rounding to the nearest tenth billed 3.3 hours, 7 minutes less than the work, mostly because the 2-minute email rounded to zero. With a 0.1 minimum on that email, the nearest-tenth total is 3.4 hours, within a couple of minutes of the real time.
Neither result is wrong if it is the agreed rule. The point is that "6-minute billing" on its own does not say which of these numbers the client will see.
Do you round each entry or the day's total?
Rounding each entry is the traditional method, because each line on a detailed invoice shows its own time in tenths. Rounding the day's total, or the total per client per day, rounds once instead of eight times, so it stays much closer to the time actually worked.
In the sample day, the total is 205 minutes, or 34.17 units of 6 minutes. Rounded up once, that is 3.5 hours ($875.00); rounded to the nearest, 3.4 hours ($850.00). Compare that with 3.9 hours when each of the eight entries is rounded up separately. The more short entries a day has, the bigger the gap, because each one rounded up can add up to 6 minutes. In the sample, the eight entries added 29 minutes between them.
Per-entry rounding is easier for a client to audit line by line, and it matches an invoice that shows every task in tenths. Per-day rounding is fairer when a day is made up of many small tasks. If you round per day but list the tasks, show the exact minutes on each line and the rounding once on the total, so the numbers on the invoice add up.
How do 6-minute increments compare with 15- and 30-minute billing?
Larger increments make the rounding gap bigger, because rounding up can add almost a whole increment to each entry. On the same sample day, rounding each entry up added 29 minutes in tenths, 65 minutes in quarter hours and 155 minutes in half hours:
| Increment | Each entry rounded up | Each entry rounded to nearest |
|---|---|---|
| None (exact time) | 3.42 h, $854.17 | 3.42 h, $854.17 |
| 6 minutes (0.1 h) | 3.9 h, $975.00 | 3.3 h, $825.00 |
| 15 minutes (0.25 h) | 4.5 h, $1,125.00 | 3.25 h, $812.50 |
| 30 minutes (0.5 h) | 6.0 h, $1,500.00 | 3.0 h, $750.00 |
Half-hour blocks rounded up turn this day into six billable hours, about 75% more than the time worked, while half-hour blocks rounded to the nearest drop four of the eight tasks to zero. Quarter hours suit work that comes in longer stretches, where the rounding is a small share of each entry. For a day full of short calls and emails, tenths keep the bill closest to the work of the three increments, whichever way you round.
How do you keep short calls and emails from getting lost?
Record them as they happen, not at the end of the day. A 4-minute call is the first thing forgotten when you reconstruct a day from memory, and in tenths it is a real line on the bill.
- Log before you hang up: start a timer when the phone rings, or add a manual entry as soon as the call ends. Thirty seconds then saves a guess later.
- Write what it was for: "Call with client re notice period" is billable and checkable. "Call" is neither.
- Keep one entry per task: listing several tasks under one total is block billing, which some clients' billing guidelines do not accept. Separate entries also make per-entry rounding honest.
- Check emails against your sent folder: at the end of the day, scan sent mail for client replies that never became entries.
- Round once, at billing: track exact minutes and apply the agreed rounding when you prepare the invoice, so you can always show the unrounded time if a client asks.
Which free time trackers round to 6 minutes?
Among the trackers compared below, Harvest offers 6-minute rounding on its free plan, limited to one seat and two projects. Toggl Track and Clockify offer it on paid plans only. The table shows where each setting applies:
| Tracker | Rounding on the free plan | Options | Where it applies |
|---|---|---|---|
| Harvest | Yes (free plan is 1 seat, 2 projects) | Nearest or up, to 6, 15 or 30 minutes, per entry | Summary reports, new invoices and budgets; timesheets keep exact time |
| Toggl Track | No, from the Starter plan | Up, nearest or down, to intervals from 1 minute to 4 hours, including 6; per entry or per group | Reports |
| Clockify | No, from the Standard plan | Up, down or nearest, at an interval you choose; per entry, then totalled | Reports, exports and billable amounts; the entries themselves are unchanged |
| Timen | No rounding setting | Tracked time stays exact; adjust hours on the invoice line | Invoice lines are editable |
All three that round apply it to reports rather than changing the original entries, and Harvest also applies it to new invoices. That is the right way round: the exact minutes stay available if a client questions a bill. If your tracker has no rounding setting, the free daily billing calculator rounds each client's daily total to 6, 15 or 30 minutes, up or to the nearest, and shows the amount at your rate. For a firm billing in tenths, see the law firm tracking workflow.
How do you convert common billing times?
- How many minutes is 0.1 of an hour?
- 0.1 of an hour is six minutes. An hour has ten tenths: 0.2 is 12 minutes, 0.5 is 30 minutes and 0.8 is 48 minutes. Multiply the decimal part of an hour by 60 to convert it to minutes.
- How do you bill a 4-minute phone call in 6-minute increments?
- A 4-minute phone call bills as 0.1 hours under both round-up and nearest-tenth billing. Rounding up, 1 to 6 minutes bills as one tenth. Rounding to the nearest tenth, 3 to 8 minutes is 0.1; anything under 3 minutes is zero unless your agreement sets a minimum charge.
- What is 1 hour 40 minutes in tenths of an hour?
- 1 hour 40 minutes bills as 1.7 hours when rounded up or to the nearest tenth. Keep the whole hour, then convert the 40 minutes: 40 ÷ 6 is 6.67 units, which rounds to 7 tenths.
- Is 6-minute billing better than 15-minute billing?
- For many short tasks, 6-minute billing stays closer to actual time than 15-minute billing. Rounding up can add up to 6 minutes per entry in tenths, against up to 15 minutes in quarter hours. In a sample day with 3 hours 25 minutes of work, rounding each entry up produced 3.9 hours in tenths and 4.5 hours in quarter hours.
What should you agree with a client before billing in tenths?
Agree four things in writing: the increment (0.1 hours), the direction (up or to the nearest), whether rounding applies to each entry or to each day's total, and whether there is a minimum charge per task. Then track exact minutes with a note on every entry, apply the rule once when you invoice, and keep the unrounded times so any line can be explained. The chart at the top of the page covers the conversion; the agreement is what makes the number on the invoice defensible.