What is IRCTC chart vacancy?
A few hours before a train departs, Railways freezes the final passenger list. That is the reservation chart, and chart vacancy is whatever is still empty once it is drawn up: berths freed by cancellations, plus quota seats nobody booked. Those go back on sale as current-availability tickets, sometimes right up to half an hour before departure. Put in your train, date and boarding point above and the page shows how many berths are open in each coach.
How do I check chart vacancy for my train?
Start with the train (number or name, either works), then the travel date and the station you're boarding from. Open a coach such as S4 or B2 to see its berth map. Travelling only part of the route? Add your destination and the map narrows to berths that are free on just that leg, which is where a lot of otherwise-hidden seats turn up.
Spotting a berth you can actually book
A fully empty berth is the easy case. The ones people miss are part-booked berths: a seat taken only between two later stations that sits free for your stretch. The map shows both, so even when the booking page flashes “regret” you can often find a berth that's confirmed end-to-end for your journey.
Reading the coach map
Each bay mirrors the real coach: Lower (L), Middle (M) and Upper (U) run down the main side, with Side Lower (SL) and Side Upper (SU) along the aisle. It pays to glance at this before booking, since a side-upper is a rough draw for an overnight trip and the map tells you exactly what you're getting.
Frequently asked questions
When does chart vacancy show up?
Once the train's chart is prepared, which these days is about 4 hours before departure for the first chart, with a second chart made closer to the train leaving. Until then there's nothing to show; check back in that window and the freed-up berths will appear coach by coach.
Can I still book a vacant berth after the chart is ready?
Yes. Berths left empty after charting are sold as current-availability tickets, with a real coach and berth number. That window stays open until roughly 30 minutes before departure, so a vacant berth here is often the quickest route to a confirmed last-minute seat.
What do coach codes like S1, B2 or A1 mean?
The letter is the class and the number is its order in the train. S is Sleeper, B is AC 3-tier, A is AC 2-tier, H is AC First, C is Chair Car, D is Second Sitting, so B2 is the second AC 3-tier coach from that class's first one.
Related: train chart preparation times · PNR status check