What is the calculation method in commodities market on the date of expiry to settle prices?
Typically most online brokerages that let you trade on commodities will ask you to square off all open position before the contract goes into delivery period.
There are certain contracts like crude which is cash settled and don't have delivery option.
But in both the cases, on the date of expiry if you haven't already squared off the contracts or it is not marked for physical delivery, all open contracts are settled based on the Due date rate.
Due date rate is calculated differently for every commodity contract,
For example in case of Aluminium it is international AL price multiplied by the currency rate on the last day of expiry.
You can see the entire list for all contracts on this MCX circular.
Thanks for the circular link, Nithin.