How it works

One calculation, four numbers

Type in a start date/time and an end date/time and the calculator runs the instant you finish typing — no submit button, no page reload. It returns four numbers at once: Total Hours (every hour that passed, no exclusions), Business Hours (only the portion inside your configured working window, on non-weekend days), Weekend Hours (everything on the days you've marked as weekend), and Weekday Hours (total minus weekend). All four update live if you change the weekend days, the business-hours window, or add holidays.

This is the calculation that trips up spreadsheet formulas the hardest: wall-clock time and business time diverge fast around a weekend. Here's a real example.

Worked example

A support ticket opens Friday at 4:30 PM and closes Monday at 9:15 AM. Weekend is set to Saturday and Sunday, business hours to 9 AM–5 PM.

Total Hours
64h 45m
Business Hours
0h 45m
Weekend Hours
48h 0m
Weekday Hours
16h 45m

By the wall clock, the ticket sat open for almost 65 hours. By business time, it was open for 45 minutes — 30 on Friday afternoon, 15 more Monday morning. That gap is the whole reason Total Hours and Business Hours get reported separately.

People reach for this version of the tool for one-off answers: how long a flight or shift actually ran, how many billable hours a single work session covers, or how long an incident stayed open when someone needs the number in the next five minutes, not after mapping spreadsheet columns. For a whole file of timestamps at once, the bulk spreadsheet calculator runs the same math across every row.

Guides

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Frequently asked questions

About the single timespan calculator

What time formats can I type into the Time field?

The calculator accepts 9:30, 930, 0930, 21:30, 2130, 9:30 AM, and 9:30PM. If you enter a value in 24-hour (military) format, the AM/PM toggle updates automatically to match.

Does the calculator account for public holidays?

Yes, optionally. Check the boxes to exclude US federal holidays and/or UK bank holidays, and Business Hours will skip those dates in addition to your chosen weekend days.

Can I change which days count as the weekend?

Yes. Friday, Saturday, and Sunday can each be toggled on or off as a weekend day, which affects both the Weekend Hours and Business Hours calculations.

What's the difference between Business Hours and Total Hours?

Total Hours counts every elapsed hour between your start and end time with no exclusions. Business Hours counts only the portion of that span falling on non-weekend days within a configurable daily window, such as 9 AM to 5 PM.

What are business day hours?

Business day hours (also called business hours or working hours) are the hours that fall within your organization's working window on non-weekend days — commonly 9 AM to 5 PM, Monday through Friday. This calculator's Business Hours result gives you exactly that figure, with the daily window and weekend days fully configurable. For a whole-day count instead, see our guide on counting business days in Excel.

Does this calculator support time zones?

Not yet — the calculator currently assumes both the start and end time are in the same local time zone. A time zone selector is on the roadmap.

Is my data sent to a server when I calculate?

No. All date math happens locally in your browser using JavaScript. Nothing you type is transmitted anywhere or stored.