Work Hours Calculator — Calculate Your Daily & Weekly Hours Instantly

What Is a Work Hours Calculator and Why Do You Need One?

Whether you are a freelancer tracking billable hours, a small business owner processing weekly payroll, or an employee verifying your pay stub, knowing exactly how many hours you worked eliminates disputes and ensures compliance with labor regulations.

There are two primary approaches to tracking time: clock-in/clock-out (recording exact start and end times) and duration-based tracking (logging total hours worked per task or project). This calculator uses the clock-in/clock-out method because it provides an auditable record that satisfies FLSA record-keeping requirements and is the standard for most hourly employment.

If you need to track hours across an entire pay period with multiple days and running totals, see our Timesheet Calculator. For a detailed walkthrough of the math behind these calculations, visit our How to Calculate Work Hours guide.

How Do You Calculate Work Hours From Clock-In to Clock-Out?

The formula is straightforward, but the base-60 arithmetic that clocks use (where 60 minutes make an hour) is where most people make errors. Here is the process broken into four steps.

Step 1 — Convert Times to a Common Format

Start by ensuring both your clock-in and clock-out times use the same format. If you are working in 12-hour format, convert to 24-hour (military) time to simplify subtraction: add 12 to any PM hour except 12:00 PM itself, and treat 12:00 AM as 0:00. For example, 5:15 PM becomes 17:15 and 8:30 AM stays 8:30.

Step 2 — Subtract Start From End

Subtract the clock-in time from the clock-out time. Handle hours and minutes separately. If the minutes in the clock-out are smaller than the minutes in the clock-in, borrow 1 hour (60 minutes) from the hours column — just like borrowing in base-10 subtraction.

Step 3 — Deduct Unpaid Breaks

Subtract any unpaid break time from the gross hours. Under the FLSA, meal periods of 30 minutes or longer where the employee is completely relieved of duties are generally unpaid. Short rest breaks of 5 to 20 minutes are typically considered compensable work time and should not be deducted.

Step 4 — Handle Overnight Shifts

If your clock-out time is earlier than your clock-in time (for example, you started at 10:00 PM and ended at 6:30 AM), the shift crossed midnight. In this case, add 24 hours (1,440 minutes) to the clock-out time before subtracting. The calculator above does this automatically whenever it detects a negative result.

How Do Overnight and Split Shifts Work?

Overnight shifts — common in healthcare, manufacturing, logistics, and hospitality — require a simple adjustment to the standard subtraction formula. When the clock-out time appears to be before the clock-in time, the shift has crossed midnight.

A split shift is a work schedule with two or more distinct periods of work separated by a non-working period longer than a typical meal break — for example, working 7:00 AM to 11:00 AM, then returning from 4:00 PM to 8:00 PM. Calculate each segment separately and sum the results. The total in this example is 4h + 4h = 8 hours.

Some states mandate additional compensation for split shifts. California, for instance, requires employers to pay a split shift premium equal to one hour at the state minimum wage when the break between shifts exceeds one hour, unless the employee's total daily earnings already exceed the minimum wage for all hours worked plus the premium. Always check your state's labor department for current requirements.

What Are the Most Common Work Hours Calculation Errors?

Even small calculation mistakes can compound into significant payroll discrepancies over weeks and months. Here are the five most frequent errors and how to avoid them.

How Does Overtime Calculation Work Under the FLSA?

Under the Fair Labor Standards Act, non-exempt employees must receive overtime pay at a rate of not less than 1.5 times their regular rate for all hours worked beyond 40 in a workweek. This is the federal minimum — many states have stricter rules.

The FLSA does not require daily overtime; it only mandates the 40-hour weekly threshold. However, several states — most notably California — also impose daily overtime requirements. California's overtime law, for example, requires 1.5x pay for hours exceeding 8 in a single day and 2x pay for hours exceeding 12 in a day. Federal overtime regulations are detailed in 29 CFR § 778.

For more precise overtime calculations with configurable thresholds and state-specific rules, use our dedicated Overtime Calculator.

*Nevada daily overtime applies when the employee earns less than 1.5 times the state minimum wage. Overtime rules vary — always verify current regulations with your state labor department.

Should You Use a Work Hours Calculator or Time Tracking Software?

A free calculator is the fastest way to check a single shift or verify a paycheck. But as your needs scale — multiple employees, project tracking, invoicing — dedicated software becomes more practical. Here is how the options compare.

For a detailed review of popular time tracking platforms with feature comparisons and pricing breakdowns, read our Time Tracking Software Comparison guide.

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