I'm from Poland and I need to know what it means to spend 16.8 hours a week on something. When I first saw 2.4 hours I thought it was 2 hours 40 minutes, but with 16.8 this interpretation makes no sense.

(Help! In Poland, we don't use this style, and I need to know this for my work.)


3 Answers 3


There are 168 hours in a week (7 x 24). Thus 16.8 hours is a tenth of a week.

16.8 hours is 16 and 8/10 hours which is exactly 16 hours and 48 minutes.

As a night-shift worker myself, working in an industry (Security) which offers 24/7/365 services, I am aware that some 24 hour payment systems work on dividing up the week into sections and one way of doing that is to use tenths of a week.

We refer to some of our customers as a 'one-six-eight' customer or an 'eighty-four' customer depending on the number of the contracted hours involved. Then those contracted hours will be divided up to give shift rotations, which can result in fractions of an hour being allotted to individual shift-workers.

Microsoft Accounting :

This article describes how to enter fractions of an hour in time sheets in Microsoft Office Small Business Accounting, in Microsoft Office Accounting Professional, and in Microsoft Office Accounting Express.

  • 16
    This coincides nicely with OP's mention of 2.4 hours (one tenth of a day). If you work 16.8 hours a week, you've averaged 2.4 hours per day.
    – Flater
    Commented Nov 8, 2017 at 9:27
  • 1
    And the factor 10 isn't just because we are used to decimal. The usual shift schedule for 24/7 operations is a 5 shift schedule so a single shift covers 33.6 hours.
    – MSalters
    Commented Nov 9, 2017 at 9:27
  • 3
    Just to clear things out: you get the minutes by doing 60 * 0.8 = 48 minutes.
    – luizfzs
    Commented Nov 9, 2017 at 18:08
  • 1
    @MSalters - Please tell me you've misworded that somehow! "a single shift covers 33.6 hours" sounds like the length of a shift (i.e. the length of continuous working by an individual) is 33.6 hours. I hope you mean that an individual on "B Shift" works a total of 33.6 hours in a week, with "B Shift" actually carrying out 4 or 5 shifts in a week.
    – AndyT
    Commented Nov 10, 2017 at 14:24

16.8 is 16 plus 8/10. As I come from England, my first instinct on seeing a "." is that it's a decimal separator. Being from Poland, I assume you would have had the same instinct had it been written "16,8", rather than expecting the punctuation to be a time separator.

I suspect you have seen this in an invoice for time spent by a company's employees working on your project. At the company I work for, I have to fill in my timesheet to the nearest half-hour (30 minutes), so an invoice might say I worked for 2.5 hours one week and 17.0 hours the next week. My wife has worked for companies where she has to fill in her timesheet to the nearest 0.1 hours (6 minutes), so an invoice might say she worked for 2.4 hours one week and 16.8 hours the next week.


It is quite simply a decimal fraction of hours and to figure the amount on a calculator it is the number of minutes in an hour which is 60, times the fraction of the hour which is .8. So 60 x .8 = 48 minutes. If you need to figure this amount for work you are doing you would take the number of minutes you work in an hour and divide by 60. So if you worked 12 minutes in an hour it would be 12/60ths of an hour, or 12 divided by 60.

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