What is margin used in Zerodha Kite?

The “Used margin” in the fund's section shows, the net margin utilized by the client. It can contain

1. Amount blocked for your open equity intraday, futures, and options positions(both intraday and delivery).
2. The amount blocked for any open order which is yet not executed.

The used margin can be both positive and negative. If the “Used margin” is positive then that means you have utilized that much amount in total that day. If the “used margin” is negative that means you might have received some funds after squaring your holdings.