7:45 or 7.75? Two ways of writing the same time
On the clock, an hour has 60 minutes. In payroll, on many timesheets and in time-tracking systems, however, people calculate in decimal hours. There the hour has 100 parts, often called industrial minutes. 7 hours and 45 minutes then appear on the sheet as 7.75 hours. It is not a different time, just a different notation.
The advantage: with decimals you can calculate normally. 7.75 hours times an hourly wage of €18 gives €139.50. That does not work directly with 7:45, because the calculator does not know that a new hour begins after 59 minutes.
The formula: minutes divided by 60
To convert minutes to decimal hours, divide them by 60. 45 minutes become 45 ÷ 60 = 0.75 hours. The full hours simply stay as they are. So 7:45 hours are 7 + 0.75 = 7.75 hours.
Going back is just as easy: multiply the decimal part by 60. 8.4 hours become 8 hours and 0.4 × 60 = 24 minutes, i.e. 8:24 hours. A common mistake is to read 8.4 as 8 hours and 40 minutes. In fact it is 16 minutes less.
Conversion table: minutes to decimal hours
- 1 minute = 0.0167 hours
- 5 minutes = 0.0833 hours
- 6 minutes = 0.10 hours
- 10 minutes = 0.1667 hours
- 12 minutes = 0.20 hours
- 15 minutes = 0.25 hours
- 20 minutes = 0.3333 hours
- 30 minutes = 0.50 hours
- 40 minutes = 0.6667 hours
- 45 minutes = 0.75 hours
- 50 minutes = 0.8333 hours
Only minute values that divide cleanly into 60 come out even, such as 6, 12, 15, 30 or 45 minutes. Everything else produces a recurring decimal. In practice it is rounded to two decimal places, so 10 minutes become 0.17 hours.
Be careful when rounding
Rounding looks small but adds up. If you work 8:10 hours every day and write it down as 8.17 instead of 8.1667, you are credited with around 4 minutes too much per month over 21 working days. Conversely, rounding down can cost you money. The most accurate approach is to add up all the minutes first and only convert the total at the end.
Example: one week in decimal time
Suppose you have the following net working times on five days this week: 8:15, 7:45, 8:30, 8:00 and 6:20 hours. Together that makes 38 hours and 50 minutes. Divide the 50 minutes by 60 and you get 0.8333. The week therefore comes to 38.83 decimal hours. If you instead convert each day individually with rounding (8.25 + 7.75 + 8.50 + 8.00 + 6.33), you also get 38.83. It matches here because only one day needed rounding.
Faster with the calculator
In the working hours calculator you automatically see every daily time and the weekly total in both notations. In the “Add & subtract times” mode you can enter any durations as 7:45 or as 7.75, even mixed, and get the total back as clock time and as a decimal. That is handy when you want to add up hours from several weeks or subtract undertime.
Want to know what your hours are worth in euros? Multiply the decimal hours by your hourly wage or use the hourly wage calculator.