Time & General
Time Zone Overlap Calculator
Enter UTC offsets and local work start/end hours for each zone to see overlap length and example UTC times.
When do two time zones overlap?
Distributed teams need the intersection of two local working windows. Enter each zone’s integer offset from UTC and local start/end hours; the calculator converts both windows to UTC and measures overlap length, with example overlap start/end in UTC. Half-hour zones and daylight-saving shifts are out of scope — keep offsets as integers for this simplified model. Use the overlap to propose a call slot, then confirm with real calendar apps. For single-zone journey maths see arrival time; for hour formats in timesheets see decimal hours.
Worked example
UTC+0 working 09–17 and UTC+5 working 09–17 → UTC windows 09–17 and 04–12 → overlap 09–12 UTC (3 hours).
Limits and assumptions
Integer offsets only; no DST database. Overnight local shifts are handled coarsely when end ≤ start by adding 24 hours.
Frequently asked questions
What is UTC?
Coordinated Universal Time — the world time reference. Offsets like UTC+1 or UTC−5 mean “one hour ahead of UTC” or “five hours behind”.
How do I enter India (UTC+5:30)?
This simplified tool needs integers — use +5 or +6 as an approximation, or pick exact times manually.
Negative offsets?
Yes — e.g. US Eastern standard as −5.
What if overlap is zero?
Widen one window or pick another day; the tool reports no overlap.