刚好 / 恰好 / 正好【gānghǎo / qiàhǎo / zhènghǎo】

刚好, 恰好 and 正好 cover the same two meanings: a coincidence that suits you, and an amount or size that is exactly right. 正好 is the common word, 刚好 is a little more spoken, and 恰好 is written.

Exactly the right amount

Before a number, all three say the amount is exact – no more, no less. 刚好 often adds that it was only just enough.

As a predicate

正好 and 刚好 can stand as the predicate, describing size, time or temperature as just right. 恰好 sits before a verb or number and doesn't end a sentence this way. None of the three takes 很.

• × 这双鞋我穿恰好 → 这双鞋我穿正好
• × 时间很正好 → 时间正好

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In a report or a story, 恰好 replaces the other two for a coincidence. In conversation it sounds stiff.