When Berlin clocks read 09:00 in January, Mumbai shows 13:30. In July, the same 09:00 in Berlin means 12:30 in Mumbai. The gap shrinks by a full hour because Central Europe moves its clocks forward for summer while India never does.
What is the time difference between CET and IST?
The offset depends on the date. Central Europe runs on CET (UTC+1) roughly November through March, putting IST 4 hours 30 minutes ahead. From late March through late October the zone switches to CEST (UTC+2), and the lead drops to 3 hours 30 minutes. India stays fixed at UTC+5:30 all year.
Why does the CET to IST gap change in summer?
India does not observe daylight saving time. Central Europe does. On Sunday 29 March 2026 at 02:00 CET, clocks jump forward to 03:00 CEST. The offset flips from +4:30 to +3:30 overnight. On Sunday 25 October 2026 at 03:00 CEST, clocks fall back to 02:00 CET and the 4:30 gap returns. The half-hour remainder never goes away: it comes from India’s permanent UTC+5:30 offset.
CET to IST conversion table
| Time in Berlin/Paris (CET/CEST) | Time in Mumbai/Delhi (IST) | Offset |
|---|---|---|
| 06:00 CET (winter) | 10:30 IST | +4:30 |
| 09:00 CET (winter) | 13:30 IST | +4:30 |
| 12:00 CET (winter) | 16:30 IST | +4:30 |
| 18:00 CET (winter) | 22:30 IST | +4:30 |
| 06:00 CEST (summer) | 09:30 IST | +3:30 |
| 09:00 CEST (summer) | 12:30 IST | +3:30 |
| 12:00 CEST (summer) | 15:30 IST | +3:30 |
| 18:00 CEST (summer) | 21:30 IST | +3:30 |
When does the clock change in Central Europe?
Two dates determine the CET to IST offset each year. In 2026, summer time starts Sunday 29 March and ends Sunday 25 October. In 2027, it starts Sunday 28 March and ends Sunday 31 October. The rule is fixed: last Sunday of March forward, last Sunday of October back. The switch always happens at 02:00 local time in the morning.
Best calling hours from India to Central Europe
Aim for 09:00 to 11:00 IST in winter. That lands at 09:30 to 11:30 CET, right when offices open in Berlin, Paris, Madrid, and Rome. In summer, shift earlier: 08:30 to 10:30 IST catches the same 09:00 CEST start. European afternoons drift into Indian evening, so real overlap ends by 13:00 IST in winter and 12:30 IST in summer.
Frankfurt and Euronext Paris open at 09:00 CET/CEST. That is 13:30 IST in winter, 12:30 IST in summer.
Which cities use CET/CEST?
Berlin, Paris, Madrid, Rome, Warsaw, Vienna, Budapest, Prague, Barcelona, Hamburg, Munich, Milan, Cologne, and Belgrade all run on Central European Time. Algiers and Tunis sit on permanent CET (UTC+1) with no summer time, so they match IST at +4:30 year-round.
On 15 January 2026, relative to CET, Mumbai is 4.5 hours ahead. On 15 July 2026, relative to CEST, Mumbai is 3.5 hours ahead.