What is the size in bytes of the string return from ObjectId.toString()

[Big_Cat_Public_Safety_Act (Why would a 300 kg wild predator be satisfied living inside a cage?)]

const myObjectId = ObjectId("507c7f79bcf86cd7994f6c0e")
const myObjectIdString = myObjectId.toString()

myObjectId has a size of 12 bytes. But what about the size of myObjectIdString?