Business visa expiry and extension details

It is extension of "stay" NOT extension of validity.   That means, if your days of stay are 30, you can extend them to stay longer than 30 days depending on the type of visa and up to the validity of the visa itself. 

The Islamic calendar is shorter than the Gregorian calendar by 11 days.  So for 6 months visa, assume that it will expire a week before the calendar days as per Gregorian calendar.  It is from issue date.  Used to be from entry date but on my last renewal, they told me to renew as per issue date.   But mine was a 2 year business visa.

Thank you so much for clarifying for me finally after so much of wrong information provided.

My last question with my business visa of 180 Days validity with 30 Days duration stay with  multiple entry . The company my visa is sponsored by is trying to extend my visa from KSA.

1) The extension will should be calculated from visa issued date or as per the date I entered into country, 25 Sept?

2)Validity of extension will be calculated as per Hijri or Geogorian Calendar?

3) After 180 days can Business visa be extended or need to renew?