4 PM PST to IST

Business-Hours Overlap Gauge

Common Pacific Call Times

One-click presets for the most-searched Pacific meeting slots.

PST → IST Hour-by-Hour Table

Need the reverse? Go from IST to PST instead.

The Offset Formula

What 4 PM PST Really Means for Overlap

Zone Reference

Offsets per the IANA tz database. India anchored to the 82.5° E meridian; US DST per the Energy Policy Act 2005.

No saved conversions yet. Tap "Save to History" to remember up to six PST → IST lookups.

How to Convert 4 PM PST to IST with the Overlap Gauge

1. Set the Pacific time — type it into the time field, or keep the default 4:00 PM to see the headline answer.
2. Pick the Pacific mode: PST (UTC-8) for November–March or PDT (UTC-7) for March–November per the Energy Policy Act 2005 schedule.
3. Watch the amber needle land on the gauge against the emerald Pacific 9–6 arc and the sky-blue India 9–6 arc — the readout shows the IST time with a "next day" flag when it rolls past midnight.
4. Check the verdict band: green means full business-hours overlap, amber means the edge of the window, red means no overlap (which 4 PM Pacific is).
5. Save the snapshot to compare call windows, or tap a preset chip for the most common Pacific meeting slots.

Why This Converter Exists

In 2026, a delivery lead in Irvine keeps pencilling a 4 PM Pacific status call with a project team in Noida, and keeps running into the same wall: 4 PM PST is 5:30 AM in India. That mismatch — an end-of-day Californian slot that becomes a 5:30 AM ask for everyone in India — is precisely the friction this business-hours overlap gauge is built to expose. India Standard Time (IST) sits at a flat UTC+5:30 and observes no daylight saving, so the only moving part is whether California is on Pacific Standard Time (PST, UTC-8) or Pacific Daylight Time (PDT, UTC-7).

The half-hour that confuses first-timers comes from Indian history. India Standard Time was standardised in 1906 and anchored to the 82.5° E meridian near Mirzapur, a single national compromise replacing the older Bombay Time and Calcutta Time of the British Raj. Because the offset is +5:30 rather than a whole number of hours, every Pacific-to-IST conversion lands on a half-hour: 4:00 PM PST becomes 5:30 AM IST the next day under PST and 4:30 AM IST the next day under PDT.

Pacific Time is the side that swings twice a year. Under the US Energy Policy Act of 2005, daylight saving begins on the second Sunday of March and ends on the first Sunday of November. From March to November California runs on PDT (UTC-7); the rest of the year on PST (UTC-8). That single hour is why 4 PM Pacific is 5:30 AM IST in winter but 4:30 AM IST in summer — India never moves, so the entire shift comes from the Pacific side, which is why the gauge below carries an explicit PST/PDT toggle.

The IANA time zone database — the tz database maintained by Paul Eggert and contributors — encodes Pacific Time as America/Los_Angeles and India as Asia/Kolkata. Asia/Kolkata has carried a flat +05:30 rule since 1945 with no daylight-saving transitions, so India never needs special-casing in software. America/Los_Angeles carries the full US DST ruleset, so any correct converter must know today's date or let you toggle the mode — the overlap gauge takes the explicit-toggle route.

GMT and UTC are used interchangeably in scheduling tools, but they differ: GMT is a time zone equal to UTC+0 on the Greenwich meridian, while UTC is the atomic standard the world's clocks track. Converting through UTC is the cleanest method: 4 PM PST is UTC-8, so UTC = 16:00 + 8:00 = 24:00 = 00:00 next day; IST is UTC+5:30, so 00:00 + 5:30 = 05:30 the next day. The gap is a fixed 13 hours 30 minutes in winter and 12 hours 30 minutes in summer.

The practical driver behind this page is the overlap problem made literal. The semicircle gauge shades the Pacific 9–6 working day against the India 9–6 working day and shows exactly where the two intersect — a thin band in the Pacific morning and India evening. A 4 PM Pacific call sits at the very end of the California day, which the gauge reveals as 5:30 AM India: deep outside the overlap, in the pre-work hours. The verdict states plainly that a synchronous status call at 5:30 AM India is not realistic.

Distributed US–India teams have wrestled with this since the offshore-IT boom of the late 1990s, when Infosys, Wipro, and TCS built delivery centres timed to overlap with US clients. The shared working window between California and India is famously thin — roughly 8:00 AM to 10:30 AM Pacific maps to about 8:30 PM to 11:00 PM India evening on PDT. A 4 PM Pacific slot falls outside that band, and the overlap gauge turns that hard-won scheduling reality into a single shareable picture for any hour you test.