1 Answer. Both cost and costed can be used; it depends on the sense in which you use them. if you use the verb cost as a linking verb to imply to have an amount of money as a price, then it doesn't change in all the tense forms i.e. the present, past, past participle. For example, it costs/cost/has cost me five dollars ...

Do you say cost or costed?

"Cost" can also mean to estimate or determine the cost of something. If you are using that meaning of the word "cost," then "costed" is the past tense and the past participle. So if some accountants wanted to total up a business's expenses, you could say they costed out the expenses.

Is costed past tense of cost?

If it's being used as a verb, the past tense of "cost" is "costed".