What is the best way to charge a client for freelance translation tasks (per page, per word, per hour, etc...)?

For oral translation, per hour. For written translation, per word or per page (a page is usually defined in terms of number of characters with spaces). Sometimes it is determined by the client.

for me, per page is the best way to charge a client for freelance translation tasks

I find charges according to the number of pages to be more satisfying to both

the best way to charge a client for freelance translation tasks is per hour orally and per page in writing 

The best way to charge a client for translation is word honestly. It is difficult to measure words, may be more or less. Secondly, an expert may translate more words/pages than a fresher. so per hour/ pages may be ignored if true.

I think that per hour is not a good idea, because some texts will not take that much of a time so it's unfair. However, I prefare both per word and per page, depending on the length of the text. If it is more than one page, it's best to charge clients per page, and if it is one page or less, then it is best to charge per word.  

You can either charge by word or by page. It is better to know your rates for both. For example 0.5 per word = 125 riyals per page (250 words). For noneditable PDF documents which can not be ciunted by word, you can either chatge per page or charge on the target document after completing the translation.

I think per page. Due to count words not good idea and per hour its not good idea.but some time you can estimate thetotal price by using youe sense and experience in this field .I mean some translation need more time

I think that per hour would be more beneficial.

the best method to charge Per word on the basis ,each 250 words = 1 page.

The thing is, if you don’t charge someone for your services at a price point that you think you’re worth, your potential clients won’t think you’re worth it either.

You have to know that your skills deserve the price you’re asking.