If you are designing with fixed pixels in mind, then the answer is no. You have to make it smaller, specifically to the size that his printer wants (it will vary printer-to-printer and computer-to-computer depending on settings, drivers, and margins).
However, if you start working with a more flexible model, and use CSS, you can give specific directions for printing that will make your page go from margin to margin on any printer, with any settings. It could even do so when changes from portrait to landscape. Take a look at
W3School's reference on it.