N5 — outside your level filter
〜に〜回
〜に〜かいni ... kaiN5neutral
per — how many times, or how much, fits inside one period
英会話のレッスン、週に一回だけ受けてるんだ。
eikaiwa no ressun, shuu ni ikkai dake uketeru n da.
I only take an English conversation lesson once a week. casual
この薬は一日に三回、食後に飲んでください。
kono kusuri wa ichinichi ni sankai, shokugo ni nonde kudasai.
Take this medicine three times a day, after meals. neutral
All examples4
per — a count or an amount measured against one unit of time
英会話のレッスン、週に一回だけ受けてるんだ。
eikaiwa no ressun, shuu ni ikkai dake uketeru n da.
I only take an English conversation lesson once a week. casual
この薬は一日に三回、食後に飲んでください。
kono kusuri wa ichinichi ni sankai, shokugo ni nonde kudasai.
Take this medicine three times a day, after meals. neutral
一週間に十時間くらい日本語を勉強しています。
isshuukan ni juujikan kurai nihongo o benkyou shite imasu.
I study Japanese about ten hours a week. neutral
当館では月に一度、館内の点検を行っております。
toukan de wa tsuki ni ichido, kannai no tenken o okonatte orimasu.
Here at our facility we carry out an inspection of the building once a month. formal
How it's formed1
Notes
fuses, and the count fuses on: 週三回, 一日三回),
common on labels and in speech. A counter-phrase period keeps に
(一週間に三回).