Converting military time to decimal for payroll is a two-step operation: split the four-digit timestamp into its hour and minute pieces, then divide the minutes by 60 and add that fraction to the hour. So 1745 becomes 17 + (45 ÷ 60) = 17.75, and 0830 becomes 8 + (30 ÷ 60) = 8.50. Payroll software and spreadsheets can only multiply wages against decimal hours, not raw minutes, and getting the conversion wrong is what turns a clean timesheet into an underpayment.
The Two-Step Conversion
Take any four-digit military timestamp. The first two digits are the hour, the last two are the minutes. Divide the minutes by 60, and you have the decimal fraction of an hour.
A shift running from 0830 to 1745 works out like this. Start time: 8 + (30 ÷ 60) = 8.50. End time: 17 + (45 ÷ 60) = 17.75. Total shift: 17.75 − 8.50 = 9.25 decimal hours. Subtract any unpaid meal break in the same decimal form. A 30-minute lunch is 0.50, leaving 8.75 hours of compensable time.
Not every division comes out clean. Seven minutes divided by 60 is 0.11666, and you have to decide where to cut it off. Two decimal places is precise enough for payroll and standard in most systems. Legal and consulting work often tracks to the tenth of an hour, which maps cleanly onto six-minute blocks. Pick a precision level and apply it to every entry; mixing conventions creates gaps that are hard to reconcile in an audit.
Why Minutes Are Not Decimals
The error behind most payroll disputes is treating minutes as if they already are decimals. Thirty minutes is not 0.30 of an hour. It’s 0.50, because an hour has 60 minutes, not 100. The gap looks trivial on one entry and stops looking trivial once it multiplies across a workforce.
An employee who works 7 hours and 45 minutes each day for five days actually works 38.75 decimal hours. Enter the 45 as 0.45 and the timesheet shows 37.25, shaving 1.5 hours of pay off the week. Federal law requires employers to keep accurate records of hours worked for every employee covered by minimum wage and overtime rules.1Office of the Law Revision Counsel. 29 USC 211 – Collection of Data Underpayment caused by a conversion mistake carries the same exposure as underpayment done on purpose.
Common Decimal Equivalents
A handful of minute values show up on almost every schedule. Keeping them in your head speeds up entry and flags data errors on sight:
- 6 minutes = 0.10
- 10 minutes = 0.17
- 12 minutes = 0.20
- 15 minutes = 0.25
- 20 minutes = 0.33
- 30 minutes = 0.50
- 45 minutes = 0.75
Each six-minute step adds exactly 0.10, which is why tenth-of-an-hour tracking lines up so cleanly with six-minute blocks. If your organization runs on quarter-hour increments, there are only four values you ever need: 0.00, 0.25, 0.50, and 0.75.
Shifts That Cross Midnight
Overnight shifts break the plain subtraction because the end time is a smaller number than the start. A shift from 2200 to 0600 looks like it should give a negative result. Add 24 to the end time before subtracting: (6.00 + 24) − 22.00 = 8.00 decimal hours.
The same fix handles minutes. A shift from 2245 to 0715 becomes (7.25 + 24) − 22.75 = 8.50 decimal hours. Most payroll systems apply this correction automatically, but knowing the math lets you spot a system that isn’t.
Rounding and the 7-Minute Rule
Federal regulations allow employers to round employee start and stop times to the nearest five minutes, sixth of an hour, or quarter hour, provided the rounding doesn’t shortchange workers over time.2eCFR. 29 CFR 785.48 – Use of Time Clocks The most common version is quarter-hour rounding, which produces the 7-minute rule: 1 to 7 minutes past the quarter hour rounds down; 8 to 14 minutes rounds up to the next quarter.3U.S. Department of Labor. Fact Sheet 53 – The Health Care Industry and Hours Worked
A rounding policy can look neutral on paper and still violate the law if it consistently favors the employer. If the time clock sits somewhere that forces workers to clock in a few minutes early but clock out on the dot, the rounding always trims the front of the shift and never the back. Periodic audits of rounding data are the only way to confirm the policy stays neutral in practice.
Turning Decimal Hours Into Pay
Once total decimal hours are in hand, gross pay is a single multiplication. An employee earning $22.00 an hour who logs 38.75 decimal hours earns $22.00 × 38.75 = $852.50. That 0.75 represents $16.50 the employee earned and is legally owed.
Overtime raises the stakes at the 40-hour line. Hours beyond 40 in a workweek must be paid at 1.5 times the regular rate. At 43.25 decimal hours, the first 40 pay at $22.00 for $880.00, and the remaining 3.25 pay at $33.00 for $107.25, totaling $987.25. A decimal error on either side of the 40-hour mark shifts pay in the wrong direction.
Employers who violate minimum wage or overtime provisions are liable for the unpaid wages plus an equal amount in liquidated damages, effectively doubling the exposure.4Office of the Law Revision Counsel. 29 USC 216 – Penalties A single $16.50 shortfall isn’t just $16.50 at risk once you multiply it across a workforce and a stretch of pay periods.
How Long to Keep the Records
Two federal retention windows overlap on the same data. Under the Fair Labor Standards Act, payroll records including daily and weekly hours worked must be preserved for at least three years from the last date of entry.5eCFR. 29 CFR 516.5 – Records to Be Preserved 3 Years The records themselves must capture specific data points for each covered employee, including the regular hourly rate, daily hours, and weekly hours.6eCFR. 29 CFR 516.2 – Employees Subject to Minimum Wage or Minimum Wage and Overtime Provisions
The IRS sets a separate, longer requirement: employment tax records must be kept for at least four years after the tax becomes due or is paid, whichever is later.7Internal Revenue Service. Topic No. 305, Recordkeeping Because payroll feeds directly into tax filings, keeping decimal time records for at least four years satisfies both obligations at once. Whether the storage is digital or paper, the records have to be legible and retrievable. Label fields, document any rounding conventions in use, and make sure someone other than the person who built the system can produce the records if a regulator asks.