大切 vs 大事
JLPT N5 vocabulary · what is the difference?
These two genuinely overlap, and in most sentences about people or possessions either one is fine — 家族は大切です and 家族は大事です are both natural. The tendency is that 大切 leans toward what you cherish and want to protect, while 大事 leans toward what matters practically or is serious: 大事な話 (an important talk), 大事な試験 (a crucial exam), お大事に (take care of yourself).
When to use each
大切
たいせつ
Use 大切 for things and people you value and want to look after — family, friends, a keepsake, your health, your time. It carries a warmer feeling and is the safer choice in careful writing.
家族は私にとって大切です。
かぞくはわたしにとってたいせつです。
My family is precious to me.
この指輪を大切にしています。
このゆびわをたいせつにしています。
I take good care of this ring.
大事
だいじ
Use 大事 when something matters, is serious, or must not go wrong — 大事な話, 大事な会議, 大事な試験. It is also the word in the set phrases 体を大事にする and お大事に.
大事な話があるので、少し時間をください。
だいじなはなしがあるので、すこしじかんをください。
I have something important to discuss, so please give me a moment.
体を大事にしてください。
からだをだいじにしてください。
Please take care of your health.
Sentences where only one works
お大事に。
おだいじに。
Take care. (to someone who is unwell)
A fixed phrase. お大切に does not exist, so 大切 can never be substituted here.
明日は大事な試験があります。
あしたはだいじなしけんがあります。
I have a crucial exam tomorrow.
The exam matters; it is not something you cherish, so 大事 is the natural choice. 大切な試験 is not wrong but sounds slightly off.
友だちを大切にしてください。
ともだちをたいせつにしてください。
Treasure your friends.
Cherishing a person is 大切's home ground. 大事にする also works here, but 大切 sounds warmer.
水は生活にとって大切です。
みずはせいかつにとってたいせつです。
Water is vital to daily life.
A general, slightly formal statement of value — 大切 is the default in this kind of written sentence, while 大事 would sound more conversational.
Common mistakes
お大切に。
お大事に。
The parting phrase for someone who is ill is fixed as お大事に. Learners generalise from 大切にする and produce a phrase nobody says.
大切な話があります。 (when you mean an urgent, serious talk)
大事な話があります。
Not ungrammatical — 大切な話 does exist — but when you mean "we need to talk, this is serious", native speakers reach for 大事な話. 大切な話 sounds more like a treasured story.
Frequently asked questions
Is there a rule that tells me which one to use?
Not a reliable one, and you should be suspicious of any page that gives you a clean rule. For people and possessions both words are used constantly and either is fine. What does hold: お大事に and 大事な話 are fixed with 大事, and 大切 is a little more common in careful writing.
Which one is more polite?
Neither is more polite. 大切 sounds a touch softer and more formal in writing, while 大事 is very common in everyday speech. Politeness comes from です and ます, not from the choice between these two.
Are 大切にする and 大事にする the same thing?
Almost. Both mean to treasure something or take good care of it. 大切にする is preferred for people and precious objects; 大事にする is the usual one for looking after your body or health, as in 体を大事にする.