Count Hours Calculator - Calculate Work Hours Between Dates

What is a count hours calculator?

A count hours calculator finds the total number of hours worked over a span of dates. It multiplies the number of calendar days in the range by the average number of hours worked each day. People use it to total up hours for timesheets, freelance invoices, payroll periods, and project logs.

How to calculate hours between two dates

The calculator uses two steps.

First, it counts the days between the start date and the end date, including both endpoints:

Number of Days = End Date − Start Date + 1

Adding 1 makes the count inclusive, so a range that starts and ends on the same day equals 1 day, not 0.

Second, it multiplies that day count by the daily hours entered:

Total Hours = Number of Days × Daily Hours

The calculator counts every calendar day in the range, including weekends and holidays. It does not detect or remove non-working days on its own. If a person only wants hours for weekdays, they need to either enter an average that already accounts for days off, or calculate each work stretch separately and add the results.

The result is rounded to two decimal places.

Worked example

Start Date: 2023-01-02 (a Monday) End Date: 2023-01-06 (a Friday) Daily Hours: 8

Number of Days = 6 − 2 + 1 = 5 Total Hours = 5 × 8 = 40

Working 8 hours a day from Monday through Friday gives 40 total hours.

Example with a weekend included

Start Date: 2023-03-20 (a Monday) End Date: 2023-03-26 (the following Sunday) Daily Hours: 8

Number of Days = 7 (Monday through Sunday, inclusive) Total Hours = 7 × 8 = 56

Because the calculator counts every calendar day, the two weekend days are included in this total. Someone who worked only the five weekdays in this range, at 8 hours each, would have 40 hours, not 56. To get that figure from this tool, they would need to calculate the weekdays as a separate range (Monday to Friday) rather than entering the full week.

How to use the calculator

1. Enter the start date of the period.
2. Enter the end date of the period.
3. Enter the average number of hours worked per day, from 0 to 24. Decimal values are allowed, such as 4.5 for four and a half hours.
4. Read the total hours shown below the fields.

The end date must not fall before the start date. If it does, the calculator shows an error instead of a result.

More examples

Two-week pay period: 2023-01-01 to 2023-01-14, at 6 hours a day. Number of days = 14. Total hours = 14 × 6 = 84.

A full month: 2023-02-01 to 2023-02-28 (February 2023, not a leap year), at 4.5 hours a day. Number of days = 28. Total hours = 28 × 4.5 = 126.

A single day: 2023-03-15 to 2023-03-15, at 3.5 hours. Number of days = 1. Total hours = 3.5.

Frequently asked questions

Does the calculator skip weekends? No. It counts every calendar day between the start and end dates, including Saturdays, Sundays, and holidays. To find hours for weekdays only, calculate each work period as its own date range and add the totals.

Why does a one-day range count as 1 day instead of 0? The calculator counts both the start date and the end date. A range that starts and ends on the same date spans that one full day, so it counts as 1, not 0.

Can I enter part-time or fractional hours? Yes. The daily hours field accepts decimals, so a part-time schedule of 4.5 hours a day can be entered directly.

What happens if I set the end date before the start date? The calculator shows an error message and does not display a total, since a negative number of days is not meaningful.

Does the calculator account for leap years? Yes. It counts real calendar days, so February in a leap year correctly contributes 29 days instead of 28.

Is this the same as billable hours? Not necessarily. Total hours from this calculator covers every hour entered for the period. Billable hours are whichever of those hours a contract allows a person to charge to a client, which can be a smaller number.

References

1. "Time Tracking." Wikipedia, Wikimedia Foundation, https://en.wikipedia.org/wiki/Time_tracking.
2. "Fair Labor Standards Act of 1938." United States Department of Labor, https://www.dol.gov/agencies/whd/flsa.