The standard voltage in Saudia is 220v, so only if your laptop AC adapter isn't already 110-240v (most are), you'll need a step-down converter.

But probably of greater relevance are the plug adapters and, if you're going to be using dialup, the phone jack adapters.

A standard set of plug adapters that you can buy from Target or even Walmart will do you fine; as for phone adapters, they run the gamut from the US RJ11 to the funky German long and thin slot shape.

Give wherever you'll be staying a query as to what outlets they have.

Salaam aleikum.