Costed or Cost – What is the Past Tense of Cost?

Many people are confused about the past tense of the word “cost.” Some people believe that cost and “costed” are interchangeable. But make no mistake, “cost” is the correct past tense version of cost. However, “costed” is also a word, and it is grammatically correct to use it in some cases. It’s just not the past tense version of cost.

Cost Vs. Costed

When most people use the word “cost,” it is in a sentence detailing how they spent money or something else that is valuable on something. Cost is about the value of things, be it time, money, effort, etc. Costed, on the other hand, is tied specifically to an accounting or financial situation. In such situations, the word “costed” refers to speculation on how much something will cost.

We get that this is a little confusing, so here are some examples of how both words are properly used in a sentence:

  • Filling up my gas tank cost me forty dollars.
  • I bought a sandwich for lunch yesterday, but it only cost me seven dollars.
  • I’m not sure how much my order yesterday really cost me.

All of the above sentences use “cost” in the past tense, referring to an earlier period of time when someone spent money. This would be the correct way to say these sentences. You would never use “costed” in any of these situations. The cases in which you would use that word are very niche:

  • Has our upcoming project been costed yet?
  • Our manager has costed the needed materials at $200 apiece.
  • We have not costed the project, so we don’t know how expensive it will be to complete.

In this context, “costed” is mostly used as a synonym for “estimate or estimated the price of.” It’s a short way of referring to the process of estimating how much something will cost, not how much something in the past cost. Unless you are in business or government, there will be very few times when you need to use the word “costed.”

In everyday common language, the word “cost” will almost always be the grammatically correct word you are looking for. After all, for most people, the word “cost” is used to talk about how much they had to spend on something. In such a situation, you will always be looking for the past tense of “cost,” which is in itself also “cost.

Do You Need To Use Costed in Business Context?

While business context is about the only place you could use the word “costed” correctly, it still doesn’t sound very organic to say it in most situations. It just doesn’t sound right, for the most part. Even though it would be technically correct, you’d probably be better off using more organic speech, such as saying “I’ve estimated the cost of the project.”

Just make sure you don’t confuse it as the past tense version of cost, which it isn’t. Don’t be confused by the general rule of thumb: adding -ed to a word does not automatically make it past tense!