Free calculator
Time calculator
Measure how long between two date-times, shift a deadline by days, hours, or minutes, and add or subtract clock-style durations (H:MM or H:MM:SS). Math uses your browser’s local time zone—not a multi-city time-zone planner. For workbook parity, use the Google Sheets & Excel section below.
When to use this calculator
Fast checks that mirror how people plan in calendars and spreadsheets—without leaving the page.
- See how many days and hours sit between two milestones or meeting times.
- Move a launch or renewal date forward or backward by a few days and working hours.
- Add two billable blocks or subtract a break from a logged chunk when you only have clock durations.
- Sanity-check the same idea you will later formalize in a Google Sheet or Excel timeline.
Each tab answers one common question: elapsed time between two instants, shifting an instant by a duration, or pure hours-and-minutes arithmetic.
Duration between two date-times
Subtract the start instant from the end instant and break the positive difference into days, hours, minutes, and seconds. If the end is before the start, the tool stops with an error instead of guessing.
Add or subtract days, hours, and minutes
Convert the offset to milliseconds on top of the base Date, using ordinary calendar arithmetic in your local zone. Large offsets are fine; extreme values may hit JavaScript date limits.
Hours and minutes as durations
Parse each side as H:MM or H:MM:SS, convert to total seconds, then add or subtract. Results can be negative—useful for net time after removing a block. Working in total seconds matches how you reconcile seconds or decimal hours in a sheet before applying a duration format.
This is not a time-zone converter: it never interprets one city’s wall clock in another region.
Daylight saving jumps and contract cutoffs belong in a sheet with explicit rules—see the FAQ.
Google Sheets & Excel
Copy these patterns into your cells—replace references with your own (A2, B2, …). Format duration cells as Duration or Time where noted.
=B2-A2Put the earlier instant in A2 and the later in B2. Apply Format → Number → Duration (Sheets) or a custom [h]:mm:ss style in Excel for long hour totals.
=TIME(2,30,0)+TIME(1,15,0)Replace hours/minutes/seconds with your values—or point TIME at cells. Wrap with MOD(...,1) when you only care about the same-day clock portion.
=NETWORKDAYS(A2,B2)Optional holidays range as the third argument when your model excludes specific dates.
Frequently asked questions
What does this time calculator do?
Three jobs in one page: elapsed time between two date-times, shift a date-time by days/hours/minutes, and add or subtract plain H:MM durations. It uses your browser’s local time zone—not a flight-planner style multi-city clock.
Can a time calculator add time?
Yes—use Add / subtract to move a date-time by days, hours, and minutes, or Hours & minutes to add two H:MM / H:MM:SS durations (or subtract B from A). That is everyday elapsed-time math, not payroll rounding rules (for example a “seven-minute rule”) or a dedicated punch-clock product.
Is this a time zone or world-clock tool?
No. For “9:00 a.m. in Tokyo when it is 4:00 p.m. in New York,” use a dedicated time-zone product or explicit UTC offsets in a sheet. This page keeps everything in one local wall-clock context.
How do I match the “Between” tab in Google Sheets or Excel?
Store each instant in a cell and subtract: =later-earlier. Apply a duration number format so Excel/Sheets shows hours beyond 24 cleanly ([h]:mm style in Excel).
How do I add two clock-length times in Sheets or Excel?
Use TIME(h,m,s) for each piece, then add the results—same idea as the Hours & minutes tab. For overnight shifts, pair TIME with MOD patterns from your workforce policy.
What about daylight saving time?
The page uses the normal JavaScript clock for your locale. On DST transition days, “missing” or “repeated” hours follow the browser/OS—not payroll law. Model sensitive windows explicitly in a sheet with rules you control.
Why can the hours-and-minutes result be negative?
When you subtract the second duration from the first, a shorter first block yields a negative total. That is intentional for “net time remaining” style checks.
Does order matter in the Between tab?
Yes. Enter the earlier instant as Start and the later as End. If the end is before the start, the page shows an error instead of a negative breakdown.
Are results guaranteed for legal or billing deadlines?
No. This page is a free educational helper. Deadlines, SLAs, and payroll have jurisdiction-specific rules—verify with authoritative calendars and professionals when it matters.