What is the difference between the following two sentences? She goes to the forest three times per week. She goes to the forest three times a week.
meaning - Difference between "per" and "a" - English Language & Usage ...
The particular construction as per my knowledge is unnatural - as per is normally only used in reference to some prior statement / school of thought. It more properly corresponds to in accordance with, and can't simply be used to replace the idiomatic according to my knowledge / information / understanding.
"per" generally means an averaging. One may study for 5 hours one week, and 15 the next, and achieve 10 hours per week. "each" generally means either an equal distribution, or a minimum, or both. Studying 10 hours each week would mean at least 10 hours every week.
grammar - Usage of “per”, “each” and "every"? - English Language ...
The room costs 40 € per person. In this case, per has a meaning for for each. This matches with the main question as asked in the topic title, but doesn't with the example given in the thread itself: per John, as you never charge something per John, haha. There's another case where per would fit both your examples. Like this:
meaning - What does "Per [person's name]" mean? - English Language ...
The dose is usually 150 micrograms (mcg) per kilogram (kg) of body weight taken as a single dose. The treatment may be repeated every 3 to 12 months. Each tablet contains 3 milligrams (mg) of ivermectin. Weighing 85 kg or more—150 mcg/kg of body weight taken as a single dose. Weighing 65 to 84 kg—4 tablets taken as a single dose.