いっぺんに

い

っ

ぺ

ん

に

Common wordJLPTN3Freq.FrequencyTop 50,000

Meanings

1

usually written using kana alone

Describes doing multiple things simultaneously or completing something in a single action, without interruption.

宿しゅく題だいを一いっ遍ぺんに片かた付づけた。

I finished all my homework at once.

そんなにたくさんのことを一いっ遍ぺんに言いわれても困こまる。

I can't handle it when you tell me so many things at the same time.

2

usually written using kana alone

Emphasizes immediacy or suddenness, often with a nuance of something happening unexpectedly fast.

〈事こと〉を一いっ遍ぺんに済すませるto get several things done all at once
買かい物ものと用よう事じを一いっ遍ぺんに済すませた。
I finished the shopping and errands all in one go.
〈物もの〉が一いっ遍ぺんになくなるfor something to disappear all at once/suddenly
貯ちょ金きんが一いっ遍ぺんになくなってしまった。
My savings disappeared all at once.
〈事こと〉が一いっ遍ぺんに押おし寄よせるfor troubles or tasks to come rushing in all at once
仕し事ごとと家か事じが一いっ遍ぺんに押おし寄よせてきた。
Work and housework all came rushing in at once.

一いち度どにN3sense 1
一度に is the neutral, widely used word for 'at the same time/in one go', while 一遍に is more colloquial and adds a nuance of finishing everything in a single sweep.
すぐにN5sense 2
すぐに means 'immediately' with no sense of doing several things together, while 一遍に can carry both the immediacy and the 'all together' nuance.
同どう時じに sense 1
同時に is a formal, precise term for 'simultaneously', whereas 一遍に is casual and often implies bundling tasks into one action rather than strict timing.
たちまちN2sense 2
たちまち stresses the suddenness of a change happening 'in a flash', while 一遍に often focuses on something happening abruptly and completely.

徐じょ々じょにN3sense 1
徐々に describes something happening gradually, step by step, the opposite of 一遍に, which means everything happens all at once.

Derived from 一 (いち, 'one') + 遍 (へん, 'time/occurrence') + に, literally 'in one time'. The reading いっぺん is a euphonic change from いちへん.