If I get a mortgage from the bank I pay interest every month, same when I invest money, I make profit every year.

How do you call the actual amount I invested or borrowed?

It's *__ + interest* or *__ + profit*

In my native language (not English) we call it fund, does the same apply in English as well?

  • Also, correcting your English, it's, "What do you calll..." (The "how" construction is Chinese.) Mar 13, 2012 at 4:09

4 Answers 4


According to wiktionary, principal is, in finance, "The money originally invested or loaned, on which basis interest and returns are calculated". Wikipedia says essentially the same: "the original amount of a debt or investment on which interest is calculated". The macmillandictionary, on the other hand, says "in business, the original amount of money that someone borrows, which is paid back with additional money called interest" and does not extend the term to investments.


There's something of a US/UK divide on this one. Check out this NGram for spend the capital / spend the principal, and toggle the corpus between American and British. US usage is about equal for both - but the UK clearly favours capital, which accords with my own gut feel.

I think those particular search terms are appropriate here. Consider a person with no income, who lives entirely on savings. Certainly in British English, if they have sufficient savings (and interest rates are high enough) they will aspire to live entirely on the monthly interest, and not spend the capital. On the other side of the coin, if you have a mortgage, and can afford to do so, you'll often be advised to make a capital repayment, thus reducing the amount of all future payments which will be simply swallowed up by the monthly interest charge.

  • my question targeted the US English, but definitely thanks for your info. Mar 11, 2012 at 23:44
  • @Shimmy: Well, like I say, the NGram suggests that US usage is about evenly split between the two words. So other answers which only mention principal seem to be ignoring half the US usage anyway. Mar 11, 2012 at 23:49
  • @Jim: Would that were my sparkling wit showing through again! But +1 to your comment for noticing it, since I didn't at the time of writing! Isn't language marvelous? Mar 13, 2012 at 12:35

Its called "*Principal".*Principal is the amount borrowed(excluding the interest), or the part of the amount borrowed which remains unpaid.


I would say "principal plus interest" and "investment plus profit". I don't know why English speakers use two different words for borrowing and investing, but I believe they generally do.

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