If a cost is tax-deductible, you are allowed to take it off your income before the government works out how much tax you owe. So it lowers the number your tax is calculated on.

If a cost is tax-deductible如果一筆花費是 tax-deductible（可扣抵稅額）, you are allowed to take it off your income你就可以把它從收入中扣掉 before the government works out how much tax you owe然後政府才計算你要繳多少稅。 So it lowers the number your tax is calculated on所以它降低了計算稅金時所用的那個數字。

Say you earn 1,000,000 and you spent 100,000 on something tax-deductible: the tax office treats you as having earned 900,000. The important thing students get wrong is what you save — you do not get the 100,000 back. You only avoid paying tax on that 100,000, so if your tax rate is 20%, the cost really saved you 20,000.

Say you earn 1,000,000 and you spent 100,000 on something tax-deductible假設你賺了1,000,000，又花了100,000在可扣抵的東西上: the tax office treats you as having earned 900,000稅務機關就會當作你只賺了900,000。 The important thing students get wrong is what you save學生最容易搞錯的是你實際省下的是什麼 — you do not get the 100,000 back你並不會拿回那100,000。 You only avoid paying tax on that 100,000你只是不用為那100,000繳稅, so if your tax rate is 20%所以如果你的稅率是20%, the cost really saved you 20,000這筆花費其實只幫你省下20,000。

Typical examples: business expenses, charity donations, some insurance, some medical costs, certain loan interest.

Typical examples常見的例子包括: business expenses, charity donations, some insurance, some medical costs, certain loan interest營業費用、慈善捐款、部分保險、部分醫療費用，還有某些貸款利息。

It is an everyday word in the English-speaking world because people there file their own tax returns and talk openly about this. The hyphen is usual before a noun ('a tax-deductible donation'); after the verb, you will see it both with and without ('the donation is tax deductible'). People also shorten it to just 'deductible'.

It is an everyday word in the English-speaking world在英語系國家這是個很日常的字, because people there file their own tax returns and talk openly about this因為那裡的人自己報稅，也很公開地談這件事。 The hyphen is usual before a noun連字號通常出現在名詞前面 ('a tax-deductible donation')（像 'a tax-deductible donation'）; after the verb在動詞後面, you will see it both with and without連字號有沒有都會看到 ('the donation is tax deductible')（像 'the donation is tax deductible'）。 People also shorten it to just 'deductible'人們也會簡稱它為 'deductible'。