Convert time between UTC offsets

Enter a source stamp such as 2024-06-15T14:30:00, a from_offset of plus two hours, and a to_offset of minus five hours, and the tool yields 2024-06-15T07:30:00 at the target with a matching UTC Zulu stamp, signed hour shift, and calendar-day note when midnight is crossed.

Fixed UTC offsets versus named zones and why wall-clock conversion matters

Fourteen hours is the practical outer bound of real civil offsets in widespread use; values beyond that range are treated as data-entry errors rather than exotic half-day schemes, and they fail with invalid_input before any conversion runs.

How to call the API and how to read every field in the response

POST a JSON body with three required fields. The field datetime is an ISO-8601 wall-clock string: four-digit year, month, day, a T or space separator, hours and minutes, optional seconds, optional fractional seconds that are truncated to whole seconds, and an optional trailing Z or numeric offset that is accepted only so the wall components can be parsed—from_offset remains the authoritative source offset for the conversion. Aliases for datetime include dt, time, when, timestamp, and datetime_in. The field from_offset is the source fixed offset in hours, and to_offset is the target; each accepts a finite number such as two, minus five, or five point five, or a string such as plus zero two colon zero zero or minus zero five colon thirty, and each must lie within minus fourteen to plus fourteen hours inclusive. Aliases for from_offset include from, offset_from, source_offset, and utc_from; aliases for to_offset include to, offset_to, target_offset, and utc_to. On success the response echoes datetime_in as the normalized wall stamp without an offset suffix, datetime_in_iso with the source ±HH:MM attached, from_offset and to_offset as rounded hour numbers, from_offset_label and to_offset_label as short UTC± strings, offset_diff_hours as to minus from, datetime_out and datetime_out_iso for the destination wall clock, utc_iso for the same instant in Zulu, year month day hour minute second as integers of the destination civil clock, day_offset as how many midnights were crossed, day_note and message as short English summaries, formula as a one-line identity, and steps as an ordered array of substitution lines you can show next to the answer. Failed validation—missing fields, non-finite offsets, offsets outside ±14, malformed ISO strings, impossible calendar days such as 2023-02-29, or hours outside zero through twenty-three—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item.

Practical tips, limits, related searches, and where this tool fits

Keep both offsets inside the published plus-or-minus fourteen hour window; values such as fifteen or minus fourteen point one are rejected so callers cannot invent impossible civil offsets. Prefer fractional hours for half-hour and three-quarter-hour zones—five point five for India, five point seven five for Nepal, nine point five for parts of Australia—rather than smuggling minutes into a separate field that does not exist for the offset itself. Prefer this capability when you already hold an explicit ISO stamp and two fixed UTC± labels; if you only need the numeric hour gap without shifting a stamp, use the offset-difference helper instead; if you only have city names, resolve offsets first or use a DST-aware zone tool. Round-trip checks are easy: convert A to B, then B back to A with swapped offsets, and confirm the original wall clock returns after the same absolute instant is reconstructed. Remember the signed shift is always to_offset minus from_offset: if the source is UTC plus two and the target is UTC minus five, offset_diff_hours is minus seven, so fourteen thirty at the source becomes seven thirty the same calendar day at the target. Crossing midnight sets day_offset to plus one or minus one and the day_note string explains which side of midnight the destination lands on. Pair examples when teaching: same offset leaves the wall clock unchanged; whole-hour westbound conversion subtracts hours; eastbound adds hours; a half-hour offset produces a thirty-minute shift; an out-of-range offset demonstrates the hard invalid_input path. This landing targets people searching for convert time between UTC offsets, fixed offset wall clock converter, or ISO datetime from one UTC offset to another; it is not a flight-duration calculator, not a daylight-saving advisor, not a city-name zone converter, and not a pure hour-difference tool without a datetime. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately send offset fifteen.