Learn Hardcore Korean: gyesaneul machigo geoseureumdoneul hwaginhaesseoyo. - I finished paying and checked the change.

계산하다 means ‘to pay (the bill)’ or ‘to settle payment’, and 마치다 means ‘to finish’ or ‘to complete’. When you say 계산을 마치다, it literally means ‘to finish paying’. The -고 at the end is a connective ending, so 계산을 마치고 translates as “after finishing (the) payment” or “having completed the payment.”

What role does the -고 ending play in 마치고?

The suffix -고 attaches to a verb stem to link two actions performed by the same subject. It can mean “and” or indicate sequence (“after doing X, then Y”). In 계산을 마치고 거스름돈을 확인했어요, -고 tells us you first finished paying (계산을 마치다) and then checked your change.

Can I use 계산을 끝내고 instead of 계산을 마치고?

Yes. 끝내다 and 마치다 both mean ‘to finish’ or ‘to complete’, so 계산을 끝내고 is grammatically fine and very similar in meaning. Nuance-wise, 끝내다 sometimes feels a bit stronger (to bring something to a complete end), while 마치다 is more neutral. In everyday speech, they’re largely interchangeable here.

What exactly is 거스름돈, and are there synonyms?

거스름돈 literally breaks down to ‘money that’s returned’ and means the “change” you get back after paying. A common synonym is 잔돈, which also means spare change. Both refer to the leftover coins/bills returned by the cashier.

Why does the sentence use 확인했어요 instead of simply 봤어요 (“saw”)?

확인하다 means ‘to check’ or ‘to confirm’, implying you made sure the amount was correct. 봤어요 only means ‘saw’ or ‘looked (at)’, which doesn’t carry the nuance of verifying. Saying 거스름돈을 확인했어요 clearly states you counted or checked the change for accuracy.

Could I say 거스름돈을 받았어요 instead of 거스름돈을 확인했어요?

You can say 거스름돈을 받았어요 (“I received the change”) if you just want to express that you got your change. But that doesn’t imply you checked it. If your point is “I took the change and then made sure it was correct,” you’d say 거스름돈을 받고 확인했어요 or just 거스름돈을 확인했어요.

How would this sentence look in a more formal or written style?

In formal speech or writing, you can:

Replace -고 with -한 후(에) to mean “after.”
Use the formal verb ending -습니다.
A polished version is:
“계산을 마친 후에 거스름돈을 확인했습니다.”

Is it okay to replace 마치고 with 마친 후에 in casual conversation?

Yes. 계산을 마친 후에 거스름돈을 확인했어요 means the same thing. -고 is shorter and more colloquial, while -후에 (after) is a bit longer but perfectly natural—even in speech, when you want to emphasize the sequencing.