What is the PST to IST Converter?
This tool converts a time in Pacific Standard Time (PST, UTC−8) to India Standard Time (IST, UTC+5:30). Because India is 13 hours and 30 minutes ahead of the US Pacific zone during standard time, the converter simply adds 13:30 to the PST value and rolls the result over to the next day when needed.
How to use it
Enter the PST hour (0–23, 24-hour clock) and minute (0–59). The calculator returns the equivalent IST time and tells you whether the result falls on the next day. For example, a late-evening time in California often lands the following morning in India.
The formula explained
The conversion is a fixed offset: \(\text{IST} = \text{PST} + 13\text{ hours } 30\text{ minutes}\). Internally the tool converts the PST time to minutes after midnight, adds 810 minutes (\(13 \times 60 + 30\)), then takes the result modulo 1440 (minutes per day) to wrap around midnight. The day offset is how many whole days were crossed.
$$\text{IST} = \left(\left(\text{PST Hour} \times 60 + \text{PST Minute} + 810\right) \bmod 1440\right)$$
$$\begin{gathered} \text{IST}_{\min} = \Big(\big(\text{PST Hour} \times 60 + \text{PST Minute}\big) + 810\Big) \bmod 1440 \\[1.5em] \text{where}\quad \left\{ \begin{aligned} \text{IST Hour} &= \left\lfloor \tfrac{\text{IST}_{\min}}{60} \right\rfloor \\ \text{IST Minute} &= \text{IST}_{\min} \bmod 60 \end{aligned} \right. \end{gathered}$$
Worked example
Suppose it is 10:00 PST. Adding 13:30 gives 23:30 — so it is 23:30 IST the same day. Now take 20:00 PST: \(20{:}00 + 13{:}30 = 33{:}30\), which wraps to 09:30 IST the next day.
FAQ
Is IST always 13:30 ahead of PST? This converter assumes Pacific Standard Time. During US daylight saving (PDT, UTC−7) the difference shrinks to 12 hours 30 minutes, since India does not observe daylight saving.
What does "next day" mean? If adding the offset pushes the time past midnight, the IST result falls on the calendar day after the PST date.
Does India use daylight saving time? No. IST stays at UTC+5:30 all year, so only the US clock change affects the gap.
