What a pip is worth, how big a lot is, and when each one is in session. Eleven instruments, the same conventions the calculators use.
A standard lot is 100,000 units of the base currency for every pair on this page, and 100 ounces for gold, and 5,000 ounces for silver. Those three numbers are not interchangeable, and the same lot size means a very different amount of money in each case.
That is the reason each instrument has its own page rather than one table for everything: the arithmetic changes, and so does the mistake it is easy to make. The lot size calculator and the pip value calculator use exactly the conventions listed here.