This is how we work at Centoservizi:
The page is the unit of measure of translations for our company; it consists of 1500 characters typed in MS Word.

To count them in the source language, open the "Word count" function in Tools.
Divide characters spaces included by 1500. The result is the number of pages of the document.
Translations are invoiced cumulatively at the end of the month.
Payment is by bank receipt, bank transfer or PayPal® at 30 days from the end of the month.
If you would like to receive an estimate, fill out the request form.
