Difference between こぼれる and あふれる

Question

What is the difference between the two words こぼれる and あふれる?

I think for こぼれる, the focus is on improper or bad containment leading to overflow/spillage.
And for あふれる the focus is on the abundance of the object being contained, therefore leading to overflow/spillage.

As an aside, how frequently is the kanji 溢 used for あふれる and こぼれる?
I ask this because Google IME suggests 溢れる for both あふれる and こぼれる.
Is あふれる usually in kana and こぼれる usually 零れる?

Answer 1

Yes, your analysis is correct. As a Christian, 溢れる is used often in church, the Bible, etc. to describe such as God's overflowing love (神様の溢れ出る愛), overflowing joy, etc. And I usually see it written using the kanji 溢.

I have never seen こぼれる written with 溢. The kanji 零 (れい) also means "zero", so it's not hard to see that spilling something might result in an amount of zero leftover. So this has a more negative connotation than 溢れる.

Answer 2

• こぼれる is the general term for "spill". It can be due to leakage, overflow, tilt, etc.
• 溢れる specifically means "spill due to overflow", or "full of" without particular mention to spill.