How to calculate permit fees / extra property tax on new addition?

[Jason S.]

I own a small 3bed/1bath 960sqft house in San Jose CA and I am looking to remodel and add a master bed and bathroom and move kitchen to added floorspace.

I heard that there is extra school fee if extension is 500 or above.  I wonder how the fee is being assessed?  Is it a one time fee or recurring like in property tax?  And how to calculate the extra fee?

And how is new property tax being assessed after the new addition?  Does it make a difference if the new addition is below or over 500 sqft?

Lastly, are there any extra permit costs if my addition is > 500 sqft?

I appreciate your comments.  Thank you in advance!