Billable hours chart

Find the minutes worked in the first column and read across to the unit your firm bills in. When time is rounded up, 1 to 6 minutes bill as 0.1, 7 to 12 minutes as 0.2, and so on up to 55 to 60 minutes at 1.0. A 13-minute call therefore bills as 0.3 and a 31-minute meeting as 0.6.

An entry longer than an hour keeps its whole hours, and only the remaining minutes are looked up, so 1 hour 13 minutes is 1.3. To turn tenths back into minutes, multiply them by 6: 0.4 is 24 minutes and 1.7 is 1 hour 42 minutes.

The coarser the unit, the more a short entry grows when it is rounded up. A 4-minute email bills as 0.1 hours in tenths, 0.17 hours in 10-minute units and 0.25 hours in quarter hours. At 400 an hour, that one email costs the client 40, 67 or 100.

Over a day of short work these differences add up rather than evening out, because every entry is rounded on its own. The billable hours calculator prices a list of entries in any of these units and shows how much the rounding added.

Rounding up is the usual default, but some engagement letters and corporate billing guidelines ask for rounding to the nearest unit instead. Rounding up can add almost a full unit to an entry, which is 5 minutes in tenths and 14 minutes in quarter hours. Rounding to the nearest unit moves an entry by at most half a unit in either direction, so the time added to some entries is offset by time taken off others.

Rounding to the nearest has one consequence that is easy to miss. In tenths, any entry of 1 or 2 minutes rounds down to nothing, and in quarter hours the same happens to anything under 8 minutes, so very short tasks drop off the bill entirely. The switch above the chart shows both methods. To see each increment as brackets of minutes, use the billing increment chart, and for the exact decimal of a time without a billing unit, use the minutes to decimal converter.