The mistake that costs people money
Seven hours and forty-five minutes is 7.75 hours, not 7.45. Minutes run to 60, decimals run to 100, and typing the minutes straight into a payroll field after the decimal point is the single most common timekeeping error there is.
| The mistake | What goes wrong | What to do instead |
|---|---|---|
| Entering minutes as decimals | "8 hours 30 minutes" typed as 8.30. But 0.30 of an hour is 18 minutes — you just lost 12 minutes. | Divide the minutes by 60. Thirty minutes is 0.50, so enter 8.50. |
| Subtracting clock times as numbers | 9:45 AM to 6:20 PM calculated as 6.20 − 9.45. The arithmetic is meaningless. | Convert to 24-hour first: 18:20 − 9:45. Borrow 60 minutes: 17:80 − 9:45 = 8h 35m, which is 8.58 decimal. |
| Rounding only downward | Always truncating to the last quarter-hour, so 8h 44m becomes 8h 30m. Over a year this is real unpaid time. | Round to the nearest increment in both directions. 8h 44m is past the midpoint, so it rounds up to 8h 45m — 0.75. |
| Forgetting the unpaid break | In at 8:00, out at 5:00 recorded as 9 hours, when an unpaid hour of lunch sits inside it. | Subtract unpaid break time before converting. 9 − 1 = 8 hours paid. |
| Adding decimals that were each rounded | Five days each rounded to two places, then summed — the rounding errors compound. | Total the minutes first, then convert once at the end. This calculator does that. |
Hours to decimal chart — minutes to decimal hours
Divide the minutes by 60. That's the whole formula — 23 ÷ 60 = 0.3833, so 8 hours 23 minutes is 8.38 for payroll. The table below has every value from 1 to 59, with both the exact figure and the two-decimal version a payroll system will accept.
The same rule scales to a whole timesheet. For weekly hours to decimal, total the minutes across the week first and divide once at the end — 38 hours 30 minutes is 38.50, not the 38.30 that a slip of the decimal point produces.
| Min | Exact | Payroll | Min | Exact | Payroll | Min | Exact | Payroll |
|---|---|---|---|---|---|---|---|---|
| 1 | 0.0167 | 0.02 | 21 | 0.3500 | 0.35 | 41 | 0.6833 | 0.68 |
| 2 | 0.0333 | 0.03 | 22 | 0.3667 | 0.37 | 42 | 0.7000 | 0.70 |
| 3 | 0.0500 | 0.05 | 23 | 0.3833 | 0.38 | 43 | 0.7167 | 0.72 |
| 4 | 0.0667 | 0.07 | 24 | 0.4000 | 0.40 | 44 | 0.7333 | 0.73 |
| 5 | 0.0833 | 0.08 | 25 | 0.4167 | 0.42 | 45 | 0.7500 | 0.75 |
| 6 | 0.1000 | 0.10 | 26 | 0.4333 | 0.43 | 46 | 0.7667 | 0.77 |
| 7 | 0.1167 | 0.12 | 27 | 0.4500 | 0.45 | 47 | 0.7833 | 0.78 |
| 8 | 0.1333 | 0.13 | 28 | 0.4667 | 0.47 | 48 | 0.8000 | 0.80 |
| 9 | 0.1500 | 0.15 | 29 | 0.4833 | 0.48 | 49 | 0.8167 | 0.82 |
| 10 | 0.1667 | 0.17 | 30 | 0.5000 | 0.50 | 50 | 0.8333 | 0.83 |
| 11 | 0.1833 | 0.18 | 31 | 0.5167 | 0.52 | 51 | 0.8500 | 0.85 |
| 12 | 0.2000 | 0.20 | 32 | 0.5333 | 0.53 | 52 | 0.8667 | 0.87 |
| 13 | 0.2167 | 0.22 | 33 | 0.5500 | 0.55 | 53 | 0.8833 | 0.88 |
| 14 | 0.2333 | 0.23 | 34 | 0.5667 | 0.57 | 54 | 0.9000 | 0.90 |
| 15 | 0.2500 | 0.25 | 35 | 0.5833 | 0.58 | 55 | 0.9167 | 0.92 |
| 16 | 0.2667 | 0.27 | 36 | 0.6000 | 0.60 | 56 | 0.9333 | 0.93 |
| 17 | 0.2833 | 0.28 | 37 | 0.6167 | 0.62 | 57 | 0.9500 | 0.95 |
| 18 | 0.3000 | 0.30 | 38 | 0.6333 | 0.63 | 58 | 0.9667 | 0.97 |
| 19 | 0.3167 | 0.32 | 39 | 0.6500 | 0.65 | 59 | 0.9833 | 0.98 |
| 20 | 0.3333 | 0.33 | 40 | 0.6667 | 0.67 |
Decimal hours back to minutes
Going the other way, multiply the decimal by 60. This chart matches the one the Bureau of Labor Statistics publishes alongside its American Time Use Survey, covering every hundredth from 0.01 to a full hour.
| Decimal | Min | Decimal | Min | Decimal | Min | Decimal | Min |
|---|---|---|---|---|---|---|---|
| 0.01 | 1 | 0.26 | 16 | 0.51 | 31 | 0.76 | 46 |
| 0.02 | 1 | 0.27 | 16 | 0.52 | 31 | 0.77 | 46 |
| 0.03 | 2 | 0.28 | 17 | 0.53 | 32 | 0.78 | 47 |
| 0.04 | 2 | 0.29 | 17 | 0.54 | 32 | 0.79 | 47 |
| 0.05 | 3 | 0.30 | 18 | 0.55 | 33 | 0.80 | 48 |
| 0.06 | 4 | 0.31 | 19 | 0.56 | 34 | 0.81 | 49 |
| 0.07 | 4 | 0.32 | 19 | 0.57 | 34 | 0.82 | 49 |
| 0.08 | 5 | 0.33 | 20 | 0.58 | 35 | 0.83 | 50 |
| 0.09 | 5 | 0.34 | 20 | 0.59 | 35 | 0.84 | 50 |
| 0.10 | 6 | 0.35 | 21 | 0.60 | 36 | 0.85 | 51 |
| 0.11 | 7 | 0.36 | 22 | 0.61 | 37 | 0.86 | 52 |
| 0.12 | 7 | 0.37 | 22 | 0.62 | 37 | 0.87 | 52 |
| 0.13 | 8 | 0.38 | 23 | 0.63 | 38 | 0.88 | 53 |
| 0.14 | 8 | 0.39 | 23 | 0.64 | 38 | 0.89 | 53 |
| 0.15 | 9 | 0.40 | 24 | 0.65 | 39 | 0.90 | 54 |
| 0.16 | 10 | 0.41 | 25 | 0.66 | 40 | 0.91 | 55 |
| 0.17 | 10 | 0.42 | 25 | 0.67 | 40 | 0.92 | 55 |
| 0.18 | 11 | 0.43 | 26 | 0.68 | 41 | 0.93 | 56 |
| 0.19 | 11 | 0.44 | 26 | 0.69 | 41 | 0.94 | 56 |
| 0.20 | 12 | 0.45 | 27 | 0.70 | 42 | 0.95 | 57 |
| 0.21 | 13 | 0.46 | 28 | 0.71 | 43 | 0.96 | 58 |
| 0.22 | 13 | 0.47 | 28 | 0.72 | 43 | 0.97 | 58 |
| 0.23 | 14 | 0.48 | 29 | 0.73 | 44 | 0.98 | 59 |
| 0.24 | 14 | 0.49 | 29 | 0.74 | 44 | 0.99 | 59 |
| 0.25 | 15 | 0.50 | 30 | 0.75 | 45 | 1.00 | 60 |
The three rounding systems
The Department of Labor's guidance on recording hours notes that where time clocks are used, employers have long recorded start and stop times to the nearest five minutes, tenth of an hour, or quarter hour. All three are accepted practice. Recording exact minutes is always acceptable too, and is what most modern software does by default.
Tenths of an hour — 6-minute blocks
Common in professional services billing. Each tenth is six minutes.
| Minutes worked | Rounds to | Decimal |
|---|---|---|
| 0–2 | 0 minutes | 0.0 |
| 3–8 | 6 minutes | 0.1 |
| 9–14 | 12 minutes | 0.2 |
| 15–20 | 18 minutes | 0.3 |
| 21–26 | 24 minutes | 0.4 |
| 27–32 | 30 minutes | 0.5 |
| 33–38 | 36 minutes | 0.6 |
| 39–44 | 42 minutes | 0.7 |
| 45–50 | 48 minutes | 0.8 |
| 51–56 | 54 minutes | 0.9 |
| 57–60 | 60 minutes | 1.0 |
Quarter hours — 15-minute blocks
Common in manufacturing and shift work. Often called the seven-minute rule, because seven minutes is the point at which rounding flips direction.
| Minutes worked | Rounds to | Decimal |
|---|---|---|
| 0–7 | 0 minutes | 0.00 |
| 8–22 | 15 minutes | 0.25 |
| 23–37 | 30 minutes | 0.50 |
| 38–52 | 45 minutes | 0.75 |
| 53–60 | 60 minutes | 1.00 |
Rounding has to be neutral
The condition attached to all of this in the Department of Labor's guidance is that the arrangement must average out, so that all the time actually worked gets counted and the employee is fully compensated over a period of time.
In practice that means rounding in both directions around a midpoint. A system that only ever rounds down — always truncating to the last completed quarter hour — fails that test. Some states have moved further and restrict rounding where exact punch times are recorded, California most notably. If your system captures the real times, paying the real times is the simplest position to defend.
What the DOL says about recorded time
A few rules from the Wage and Hour Division's guidance on hours worked are worth knowing if you are the one doing the totalling:
- Time clocks aren't required. The FLSA doesn't mandate any particular method — only that hours worked are accurately recorded.
- Voluntary early or late punches don't count. If someone clocks in early or stays late by choice and performs no work, that time isn't hours worked.
- Small discrepancies are expected. Not everyone can punch at the same instant, and minor differences between clock records and actual hours are treated as unavoidable. Large or systematic differences are a different matter and cast doubt on the records.
- Regular work always counts. Any part, however small, of fixed or regular working time has to be counted — including identifiable periods someone is routinely required to spend on assigned duties.
There is a narrow exception, the de minimis doctrine, for infrequent and insignificant periods beyond scheduled hours that can't practically be recorded — a matter of seconds or a few minutes, arising unpredictably. It is narrower than most people assume. A pre-shift equipment check that happens every single day is regular work, not de minimis, however short it is.
Worked examples
One day, exact minutes
In at 8:23 AM, out at 5:07 PM. In 24-hour terms that's 17:07 minus 8:23, which is 8 hours 44 minutes. Divide 44 by 60 to get 0.7333, so the day is 8.73 hours to two places.
At $22.50 an hour, the exact time gives 8.7333 × $22.50 = $196.50. Multiply the rounded 8.73 instead and you get $196.43. Seven cents — trivial once, but it shows why totalling in minutes and converting at the end beats converting early.
A week with overtime
| Day | In | Out | Hours:min | Decimal |
|---|---|---|---|---|
| Monday | 7:54 AM | 4:06 PM | 8:12 | 8.20 |
| Tuesday | 7:58 AM | 5:32 PM | 9:34 | 9.57 |
| Wednesday | 8:01 AM | 6:15 PM | 10:14 | 10.23 |
| Thursday | 7:55 AM | 4:50 PM | 8:55 | 8.92 |
| Friday | 8:00 AM | 3:45 PM | 7:45 | 7.75 |
| Total | 44:40 | 44.67 |
Forty hours are straight time and 4 hours 40 minutes are overtime. At $20 an hour that's $800 straight time, plus 4.6667 hours at $30, which is $140 — $940.00 gross. Work from the rounded 4.67 instead and you land on $940.10. The total here was reached by adding the minutes first and converting once at the end, rather than rounding each day and summing the rounded figures.
Converting hours to decimal in Excel
Spreadsheets store a time as a fraction of a day, not as a number of hours. That single fact explains almost every wrong answer people get, and it makes the formula shorter than expected.
| What you have | Formula | Then |
|---|---|---|
A real time value in A1, such as 8:23 | =A1*24 | Format the result as Number, not Time |
| Hours in A1 and minutes in B1, as plain numbers | =A1+B1/60 | Format as Number |
| Decimal hours in A1, going back to hours and minutes | =A1/24 | Format the result as [h]:mm |
Two things catch people out. If the converted cell still shows 8:23 instead of 8.38, the cell is still formatted as a time — change it to Number and the value was right all along. And for a weekly total, use [h]:mm rather than h:mm: the square brackets let the figure run past 24 hours instead of wrapping around to zero, which is why a 42-hour week sometimes displays as 18:00.
If you would rather not build the sheet, the timesheet templates are free Excel workbooks with these formulas already in them — they total the hours, handle shifts that run past midnight, and split overtime per workweek.
Common questions
How do I calculate decimal hours?
Divide the minutes by 60 and add the result to the hours. Six hours and 15 minutes is 6 + (15 ÷ 60) = 6.25 decimal hours. Across several days, total the minutes first and convert once at the end rather than converting and rounding each day.
How do I convert decimal hours back to actual hours?
Multiply the decimal part by 60. In 6.25 hours, 0.25 × 60 = 15, so it is 6 hours 15 minutes. The whole number is already the hours.
What is 0.22 of an hour?
13.2 minutes — 0.22 × 60 = 13.2, or 13 minutes and 12 seconds.
What is 0.42 of an hour?
25.2 minutes — 0.42 × 60 = 25.2, or 25 minutes and 12 seconds.
What is 7 hours 45 minutes in decimal?
7.75 hours. 45 ÷ 60 = 0.75.
What is 8.5 hours in hours and minutes?
8 hours 30 minutes. 0.5 × 60 = 30.
Why does payroll want decimals at all?
Because pay is a multiplication. Gross pay is the hourly rate times the hours, and you cannot multiply a rate by 8:23. Converted to 8.38, the arithmetic works.
Does this calculator save my entries?
No. Everything runs in your browser and nothing is stored or sent anywhere. Closing the tab clears it.
Sources
- Bureau of Labor Statistics — Conversion Chart: Fraction of an Hour to Minutes, published with the American Time Use Survey documentation.
- U.S. Department of Labor, Wage and Hour Division — FLSA Hours Worked Advisor: Recording Hours Worked. Rounding practice, the averaging requirement, time clock rules, and the de minimis doctrine.
- U.S. Department of Labor, Wage and Hour Division — FLSA Overtime Calculator Advisor, hours worked conversion chart.
- 29 C.F.R. § 785.48 — recording and computing hours worked.
Both conversion tables on this page were generated from the arithmetic rather than transcribed, and every value was checked against minutes ÷ 60.