「支払[期限](https://eikaiwa.dmm.com/uknow/questions/34517/)」は英語に訳せば「payment deadline」に相当します。
なので、「支払期限は[いつ](https://eikaiwa.dmm.com/uknow/questions/53271/)ですか？もう過ぎてます？」と聞きたいならこのようは自然です。
When is the payment deadline?
When in the deadline for the payment?
When is the payment due by?
例文
Naomi: Hey Andy, did you pay your school tuition yet?
尚美さん：アンディさん、まだ学費を払いましたか？
Andy: No, not yet. When was the payment due by?
アンディさん：いいえ、まだ払っていません。支払期限はいつでしたっけ？
Naomi: Tomorrow!
尚美さん：明日だよ！
Andy: Oh okay, thank you!
アンディさん：あ、そっか！ありがとう！
英語頑張って下さい！
一般に「[期限](https://eikaiwa.dmm.com/uknow/questions/34517/)、期日」はdeadline、due date で表し、
支払期限は deadline for payment、payment due date になります。
ただ、「[支払](https://eikaiwa.dmm.com/uknow/questions/34802/)期限」に直接相当するこれらの表現を使わなくても、
The payment will be due on June 1.
あるいは
Please pay by April 30.
（4月30日までにお支払いください。）
のような文で表すこともできます。
"When is the deadline for this payment?"
This is asking the person to
You: "When is the deadline for this payment?"
Person: "It looks like the deadline for your payment is the 23rd of this month."
"When is the payment due?"
This is a slightly less formal way to ask whom you owe money when you are obligated to pay.
You: "When is the payment due?"
Person: "The payment is due on the 23rd of this month, but you need some more time, I can wait."
"Has the deadline for my payment already passed?"
This is how we would ask if the money is already due to be paid to the person you owe.
You: "Has the deadline for my payment already passed?"
Person: "Actually, yes it has. And you also owe me some interest."
Note: Interest is money that is charged by a bank or other financial organization for borrowing money.
2nd example:
You: "Has the deadline for my payment already passed?"
Person: No, it hasn't yet. However, I do expect you to get the money to me on time."
When is the deadline for this payment?""
これは尋ねる時の表現です。
You: ""When is the deadline for this payment?""
支払い期限はいつですか？
Person: ""It looks like the deadline for your payment is the 23rd of this month.""
支払い期限は今月の23日のようです。
When is the payment due?
これは、借金をしていて支払う義務があることを意味する少し丁寧な表現です。
You: ""When is the payment due?""
いつが支払い期限ですか？
Person: ""The payment is due on the 23rd of this month, but you need some more time, I can wait.""
支払いの期限は今月の23日です。
少し時間があるので待っています。
Has the deadline for my payment already passed?
借金の支払いの期限がすでに迫っていると尋ねる表現です。
You: Has the deadline for my payment already passed?
支払い期限はすでに過ぎましたか？
Person: Actually, yes it has. And you also owe me some interest.
実際、過ぎています。利子の返済もすべきです。
メモ：利子は、借金をした銀行や金融機関によって異なります。
2つ目の例
You: ""Has the deadline for my payment already passed?
支払いの期限は過ぎましたか？
Person: No, it hasn't yet. However, I do expect you to get the money to me on time.
いいえ、まだです。期限通りに借りたお金を返してくださいね。
A due payment is a payment that should be paid, or is outstanding. With most bills, if not to be paid 'on receipt' as soon as you receive the bill, then there is either an official or unofficial cut of date. The bill may state for example:'Payment must be made within 7 days.'
"This payment was due on the 21st of June. It is late and you will have to pay a penalty charge for late payment."
"Did I miss the cut off date for payment?"
"Yes, it was 7 days ago."
A due payment iは、支払わなければいけない、または未払いのという意味です。ほとんどの請求書において、請求書が届いてからすぐにすぐに支払をしなければ、公式か非公式か支払期限があるでしょう。
請求書に書かれている支払期限の例として
'Payment must be made within 7 days.' 支払は７日以内にされなければならない。
"This payment was due on the 21st of June. It is late and you will have to pay a penalty charge for late payment."
7月２１日に期限がくる。もう過ぎているから、遅延金を払うことになるだろうね。
"Did I miss the cut off date for payment?"
支払期限やぶっちゃったかしら？
"Yes, it was 7 days ago."
はい、７日前です。
"When is payment due?" and "When does it have to be paid by?" asks them to tell you when it needs to be paid by.
"Have I missed the payment date?" asks them to tell you if the date has passed.
When is payment due?、When does it have to be paid by?
いつまでに支払う必要があるかを尋ねています。
Have I missed the payment date?
支払期日を過ぎているかどうかを尋ねています。
Could you tell me when is the deadline for this payment?
To ask about a deadline you could use these sentences. Please, bear it in mind that the second question is more polite due to the word "could" but it doesn't mean the first one is not suitable to ask.
アメリカ合衆国 
日本 
イギリス 
南アフリカ 
