Where is the serial number on a Indesit cooker?

Open the oven door; the rating plate is on the front edge of the oven cavity.

Where the rating plate is1
  1. On the front frame, visible with the door open

Source: Indesit ID5E92KMW/UK cooker – instructions (university-hosted copy)

How old is my Indesit cooker?

Copy the S/N number from the plate, or paste everything on it.

Indesit

All Indesit appliances