Calculator inputs
Time-to-fraction formulas
The calculator converts every duration to seconds before creating fractions. This approach keeps calculations exact when hours, minutes, and seconds appear together.
Example: forty-five minutes equals 2,700 seconds. One hour equals 3,600 seconds. The fraction 2,700/3,600 simplifies to 3/4, its decimal is 0.75, and its percentage is 75%.
Choose the mode that matches your calculation
Time Converter
Enter any nonnegative number of hours, minutes, and seconds. Choose the comparison period, preferred denominator, rounding interval, and rounding direction. The result includes an exact fraction, displayed fraction, mixed number, decimal, percentage, normalized duration, and clock notation.
Start & End
Enter clock times such as 8:15 AM, 4:45 PM, 08:15, or 16:45. Subtract up to three breaks. Enable overnight handling when the end time falls on the next day. Choose an hour, day, week, or custom shift as the comparison period.
Shift & Payroll
Enter worked time and select a 7.5, 8, 10, 12, or 24-hour shift. Add an hourly rate, regular-hours threshold, overtime multiplier, double-time threshold, and double-time multiplier. The calculator separates each pay category and estimates gross earnings.
Batch Timesheet
Add up to one hundred rows. Each row accepts a date, description, start time, end time, unpaid break, and hourly rate. Overnight rows are handled automatically. Results include row totals, daily totals, weekly totals, grand totals, and CSV export.
Understanding time fractions, decimal hours, and rounded records
A time fraction expresses a duration as part of a larger time period. Clock notation, decimal notation, and fraction notation can describe the same duration in different ways. One hour and thirty minutes may be written as 1:30, 1.5 hours, 3/2 hours, or 1 1/2 hours. The mathematical amount is identical, but different systems may require different formats.
The most familiar time fraction compares minutes with sixty minutes in one hour. Fifteen minutes becomes 15/60, which simplifies to 1/4. Twenty minutes becomes 20/60, or 1/3. Thirty minutes becomes 30/60, or 1/2. Forty-five minutes becomes 45/60, or 3/4. When seconds are present, the calculator compares total seconds with 3,600 seconds per hour, preserving an exact rational value.
Fractions can be proper, improper, or mixed. A proper fraction is less than one, such as 3/4 hour. An improper fraction is one or greater, such as 5/4 hours. A mixed number combines a whole number and a proper fraction, so 5/4 hours becomes 1 1/4 hours. The calculator shows these forms because readers and software systems may prefer different representations.
A preferred denominator creates a convenient approximation. A workplace may record time in fourths, tenths, twelfths, hundredths, or another fixed increment. For example, thirty-eight minutes is exactly 19/30 hour, but a quarter-hour report may show approximately 3/4 hour. This is a rounding choice rather than an exact identity. The result panel clearly preserves the exact fraction when an approximation is requested.
Elapsed-time calculations add another step. Gross elapsed time is the end time minus the start time. Unpaid breaks are then subtracted. If the shift crosses midnight, the end time belongs to the following day. Overnight handling adds twenty-four hours before subtracting, preventing a valid overnight duration from becoming negative.
Rounding intervals and fraction denominators solve different problems. A rounding interval changes the duration itself, while a preferred denominator changes how the resulting ratio is represented. For dependable records, preserve the original start, end, and break details. Apply only the rounding policy required by the receiving system, and keep exact values available for review.
Payroll estimates require special care. Overtime rules, daily thresholds, weekly thresholds, break treatment, and rounding requirements vary. The payroll section performs the arithmetic entered by the user, but it does not decide whether a worker is legally eligible for a particular multiplier. Official workplace policy and applicable law remain controlling.
Common minutes-to-hour fraction table
| Minutes | Original fraction | Simplified fraction | Decimal hours | Percentage |
|---|---|---|---|---|
| 1 | 1/60 | 1/60 | 0.016667 | 1.6667% |
| 2 | 2/60 | 1/30 | 0.033333 | 3.3333% |
| 3 | 3/60 | 1/20 | 0.05 | 5% |
| 4 | 4/60 | 1/15 | 0.066667 | 6.6667% |
| 5 | 5/60 | 1/12 | 0.083333 | 8.3333% |
| 6 | 6/60 | 1/10 | 0.1 | 10% |
| 7 | 7/60 | 7/60 | 0.116667 | 11.6667% |
| 8 | 8/60 | 2/15 | 0.133333 | 13.3333% |
| 9 | 9/60 | 3/20 | 0.15 | 15% |
| 10 | 10/60 | 1/6 | 0.166667 | 16.6667% |
| 12 | 12/60 | 1/5 | 0.2 | 20% |
| 15 | 15/60 | 1/4 | 0.25 | 25% |
| 18 | 18/60 | 3/10 | 0.3 | 30% |
| 20 | 20/60 | 1/3 | 0.333333 | 33.3333% |
| 24 | 24/60 | 2/5 | 0.4 | 40% |
| 25 | 25/60 | 5/12 | 0.416667 | 41.6667% |
| 30 | 30/60 | 1/2 | 0.5 | 50% |
| 35 | 35/60 | 7/12 | 0.583333 | 58.3333% |
| 36 | 36/60 | 3/5 | 0.6 | 60% |
| 40 | 40/60 | 2/3 | 0.666667 | 66.6667% |
| 42 | 42/60 | 7/10 | 0.7 | 70% |
| 45 | 45/60 | 3/4 | 0.75 | 75% |
| 48 | 48/60 | 4/5 | 0.8 | 80% |
| 50 | 50/60 | 5/6 | 0.833333 | 83.3333% |
| 54 | 54/60 | 9/10 | 0.9 | 90% |
| 55 | 55/60 | 11/12 | 0.916667 | 91.6667% |
| 60 | 60/60 | 1 | 1 | 100% |
| 75 | 75/60 | 5/4 | 1.25 | 125% |
| 90 | 90/60 | 3/2 | 1.5 | 150% |
| 105 | 105/60 | 7/4 | 1.75 | 175% |
| 120 | 120/60 | 2 | 2 | 200% |
Rounding method guide
| Method | How it behaves | Common purpose |
|---|---|---|
| Exact | Keeps every entered second without changing the duration. | Accurate records, education, science, and auditing |
| Nearest interval | Moves the duration to the closest selected minute interval. | General scheduling and reporting |
| Always round up | Moves any partial block to the next complete block. | Minimum billing blocks and reservation systems |
| Always round down | Discards the incomplete portion of the current block. | Completed-block measurements |
| Truncate | Removes the remaining partial interval without midpoint rounding. | Systems that store only completed intervals |
| Payroll 7-minute rule | Rounds around a seven/eight-minute boundary to quarter hours. | Some workplace timekeeping systems |
Worked examples
Convert 45 minutes to a fraction of an hour
One hour contains sixty minutes. Write 45/60, divide both values by fifteen, and obtain 3/4 hour. The decimal result is 0.75 and the percentage is 75%.
Convert 1 hour 30 minutes to fractional hours
Ninety total minutes divided by sixty minutes per hour gives 90/60. The simplified improper fraction is 3/2 hours, the mixed number is 1 1/2 hours, and the decimal is 1.5 hours.
Find a fraction of an eight-hour shift
Two worked hours divided by an eight-hour shift gives 2/8. Simplifying by two produces 1/4 of the shift, or 25%.
Calculate a shift with a break
A shift from 8:15 AM to 4:45 PM lasts eight hours and thirty minutes. Subtracting a thirty-minute unpaid break leaves eight hours, which equals 8/1 hours and one complete eight-hour shift.
Calculate an overnight shift
A shift from 10:30 PM to 6:45 AM crosses midnight. Adding one day to the end time creates an eight-hour and fifteen-minute gross duration. After a forty-five-minute break, the net duration is seven hours and thirty minutes, or 15/2 hours.
Input validation and dependable results
The server validates negative values, missing durations, invalid clock formats, invalid dates, breaks longer than shifts, nonpositive custom periods, unsupported payroll thresholds, and empty timesheets. Client-side previews are provided for convenience, but final results are recalculated in PHP. This keeps the calculator functional even when JavaScript is disabled and prevents browser previews from becoming the sole source of truth.
Unusual minute and second values are normalized. For example, ninety minutes becomes one hour and thirty minutes. Clock inputs accept common twelve-hour and twenty-four-hour formats. Batch rows with an end time earlier than the start time are interpreted as overnight shifts. A maximum of one hundred rows prevents accidental oversized submissions while remaining suitable for substantial timesheets.
Payroll and legal notice
This calculator provides mathematical estimates. It does not determine overtime eligibility, required break treatment, minimum wage compliance, tax deductions, employee classification, record-retention duties, or lawful rounding practices. Workplace policies and labor rules differ. Review official records and applicable requirements before using estimated payroll values for payment or compliance decisions.