Cost vs. Costed
“Cost” and “costed” can both be correct because they serve different verb senses. The ordinary price/loss sense usually stays “cost” in the past, while “costed” is standard when someone estimates or determines a cost.
Use “cost” for the ordinary past meaning “had a price” or “caused a loss”; use “costed” when the verb means calculated, estimated, or assigned a cost.
Key details
Further guidance
Core difference
Use “cost” for the ordinary past meaning “had a price” or “caused a loss”; use “costed” when the verb means calculated, estimated, or assigned a cost.
Fast Test
If you can paraphrase the verb as “was priced at / required payment,” use “cost.” If you mean “calculated the cost of,” “costed” is the appropriate regular past form.
Sense Boundary
The distinction is semantic, not merely regional: “The repair cost $500” and “The team costed the repair at $500” use different senses of the verb.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- COST — Merriam-Webster (opens in a new tab)Merriam-Webster · Direct dictionary evidence distinguishing ordinary unchanged cost from costed in the estimating/pricing sense