Seven hours and forty-five minutes is 7.75 decimal hours, because 45 ÷ 60 is 0.75. Writing it as 7.45 understates the shift by 18 minutes. Reading a payroll figure of 7.45 as "seven forty-five" overstates it by the same amount in the other direction, and both errors are common enough that timesheet software has been built specifically to prevent them.
The rule is one division and it is worth internalising: minutes over sixty, never over a hundred.
What does each fraction of an hour look like?
The clean ones are worth knowing on sight, because they cover most rostered shifts.
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 5 | 0.083 | 35 | 0.583 |
| 10 | 0.167 | 40 | 0.667 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.333 | 50 | 0.833 |
| 30 | 0.5 | 55 | 0.917 |
Only the quarter-hours land on tidy decimals, which is exactly why rotas are built on them. A shift pattern in fifteen-minute units converts without a repeating decimal; one in ten-minute units does not.
Why does crossing midnight break the subtraction?
Because subtracting clock times directly gives a negative number when the end is on the next day. A shift from 22:00 to 06:00 subtracts to −16 hours rather than 8.
The fix is to add 24 hours whenever the end time is earlier than the start, which is what any tool doing this correctly does silently. Doing it by hand is where night-shift timesheets go wrong, and it is a large error rather than a rounding.
The daylight saving article covers the related case that catches payroll twice a year: the night a shift is genuinely 23 or 25 hours long.
Where does the overtime threshold sit?
At forty hours in a workweek under the US federal rule, and elsewhere it varies — some jurisdictions count daily, some weekly, and some both.
That distinction changes the answer materially. Four ten-hour days attract no overtime under a weekly rule and eight hours of it under a daily one, for identical work. The working days article covers the same divergence for the calendar side.
Breaks are the other variable. Unpaid breaks come off the total before the threshold is applied, so a nine-hour day with an hour unpaid is eight hours worked — and whether a short rest break is paid is a matter of local rule rather than convention.
Why does the 24-hour clock still confuse people?
Because the two boundaries are the only genuinely irregular cases and they are the ones that matter. After noon, add twelve: 5:45 pm is 17:45, written 1745 in the military form. Before noon, the hour is unchanged.
The exceptions are midnight and noon. Midnight is 00:00 at the start of a day and 24:00 at the end of one, and both notations refer to the same instant from different directions — which is why "12 am Friday" is ambiguous in a way "00:00 Friday" is not.
Noon is 12:00, and 12 pm rather than 12 am, which reverses the intuition that pm hours count upward from 1. Anything scheduled at either boundary should use the 24-hour form.
Time zones make the same subtraction worse rather than harder. A shift that starts in one zone and ends in another is not a clock subtraction at all — it is two instants converted to a common reference and then subtracted, which is why anything spanning zones should be recorded in UTC and displayed locally.
What is a timecode, and why does the frame rate matter?
Hours, minutes, seconds and frames — so its meaning depends entirely on the frame rate. The same timecode of 00:01:00:12 is a different position at 24 fps and at 30 fps, because the frame count is a fraction of a second that only the rate can resolve.
Non-drop timecode counts every frame and treats the rate as exact. Drop-frame is a different scheme that skips certain numbers to keep a 29.97 fps sequence aligned with real elapsed time — it drops labels, never frames, which is the detail the name obscures.
The frame rate article covers what happens when footage is conformed between rates rather than relabelled.
Questions people ask
Why does payroll use decimals at all? Because pay is rate × hours, and multiplying by 7.75 is arithmetic while multiplying by "7 hours 45" is not. The decimal exists for the multiplication.
Should I round shift times? Rounding rules are usually regulated, and where they exist they generally require rounding to be neutral rather than consistently in the employer’s favour. The rounding article covers why repeated rounding drifts.
Is 1745 the same as 17:45? Yes — military time is the 24-hour clock written without the colon. The spoken form is different and the value is identical.
How do I total a week of shifts? Convert each to decimal, add, then split at the threshold. Adding hours-and-minutes across seven rows by hand is where the arithmetic breaks down.
Do seconds ever matter? For billing in six-minute units, which several professions use, the unit is 0.1 hours and seconds are noise. For anything measured by a machine, they are the point.
Divide by sixty and the whole family becomes one operation. The hours calculator and time duration calculator handle a single shift including the midnight case, the decimal hours converter does the conversion on its own, the weekly hours calculator totals a rota and splits the overtime, the military time converter covers the notation, and the FPS timecode calculator is the same idea at a much finer grain.