For translations I calculate the price based on the number of source words. My basic rate is €0.09 per source word. Depending on the level of difficulty, the deadline and the volume, I may charge slightly more or less.
For proofreading and copywriting I work with an hourly rate of €40 per hour. We will of course discuss in advance how many hours the job will take.
Translation agencies employ project managers and outsource the translation work to external partners. You are therefore paying not just the translator but also an intermediary – the translation agency. Going directly to the freelancer can easily produce a price difference of 40%.