What’s the Past Tense of Cost: Is It Cost or Costed?

Understanding the correct past tense of “cost” can be a bit tricky, especially for non-native English speakers and even fluent writers. At first glance, you might wonder: Is it “cost” or “costed”? Both forms exist in English, but they are not used interchangeably. Knowing the difference can help you write with greater accuracy and clarity.

The word “cost” is an irregular verb, and like many irregular verbs in English, its past tense form doesn’t follow the usual “-ed” ending rule. This often leads people to ask whether “costed” is ever correct. The short answer is: “cost” is the proper past tense when referring to the price or value of something. For example, “The dress cost $100 yesterday.” However, “costed” is used in very specific contexts, usually in business or accounting, such as “The project was carefully costed before approval.”

In this guide, we’ll explain the differences between cost vs. costed, show you how to use each correctly, and provide real-life examples to clear up any confusion. Let’s dive in and finally settle the question: What’s the past tense of cost?

Why Is There Confusion?

Let’s start with the reason everyone gets tangled up with this word.

The root of the confusion lies in how English verbs work—specifically the difference between regular and irregular verbs. Most English verbs follow a simple rule: just add “-ed” to make the past tense. For example:

• Walk → Walked
  
• Play → Played
  
• Paint → Painted
  

Easy, right? But then come the irregular verbs. These are the troublemakers. Instead of following the typical rule, they have unique past tense forms:

• Run → Ran
  
• Buy → Bought
  
• Cost → ???
  

That’s where it gets messy.

Many people automatically assume “cost” must be regular and therefore say “costed.” Others have heard “cost” being used as its own past tense and stick with that. Add to that the mix of British English, American English, and technical jargon, and it’s no wonder so many folks are confused.

The good news? Both forms are technically correct, but they’re used in very different ways—and once you learn the difference, it’s easy to spot which one fits best.

What Does “Cost” Mean?

Before diving into grammar, it’s helpful to fully understand the meaning of “cost.”

At its core, “cost” means to require a payment, effort, or sacrifice. But it can act as both a verb and a noun.

✅ As a verb:

• “How much did that car cost you?”
  
• “This mistake could cost us the deal.”
  

✅ As a noun:

• “The cost of living has gone up.”
  
• “We need to lower production costs.”
  

It also has metaphorical uses:

• “That decision cost him his peace of mind.”
  
• “The error cost them the championship.”
  

In all these examples, “cost” implies some form of loss or payment, whether it’s financial, emotional, or physical.

The Past Tense of “Cost”

Now let’s get to the grammar side of things.

“Cost” is an irregular verb—which means it doesn’t change in the past tense.

So, in everyday speech and writing, the past tense of “cost” is “cost.” Plain and simple.

• “It cost me $100.” ✅
  
• “It has cost us too much already.” ✅
  
• “How much did it cost?” ✅
  

This applies across the board in American and British English, and in most contexts, “cost” should be your go-to form.

When “Costed” Might Be Appropriate

So where does “costed” come in?

Believe it or not, “costed” is a legitimate word. But it’s not used in everyday language. Instead, it’s used in technical, deliberate, or industry-specific contexts.

🔹 Referring to Cost Analysis or Estimation:

“Costed” is often used when referring to the act of calculating or estimating the cost of something—usually in business, finance, or project management.

✅ “The construction project was costed by engineers.”
✅ “We costed the marketing plan before launch.”

In these cases, “costed” doesn’t just mean “had a price.” It means someone actively calculated the cost—which is an important distinction.

🔹 Emphasizing a Deliberate Action:

“Costed” is appropriate when you want to highlight that cost calculation was done as an intentional step.

✅ “They costed every single material before building began.”
✅ “The design options were all thoroughly costed.”

This usage is more formal and is rarely heard in casual conversation, but it’s quite common in business reports, project proposals, and corporate analysis.

🔹 Usage in Professional Jargon:

You’ll often find “costed” in industries like:

• Finance
  
• Construction
  
• Procurement
  
• Accounting
  
• Project Management
  

It adds a layer of technicality and precision to the language.

So, while “cost” is still technically correct in most situations, “costed” sounds more professional in certain contexts where estimation or analysis is being emphasized.

Verb Tenses for “Cost”

Let’s break it down in a quick-reference chart that shows how “cost” behaves across verb tenses:

“Cost” and “Costed” in Sentences

Let’s look at how each form appears in real sentences.

✅ Examples with “Cost” (Correct in Most Contexts)

• “The dinner cost me fifty bucks.”
  
• “His mistake cost the team the game.”
  
• “The phone cost more than I expected.”
  
• “That trip cost them their savings.”
  
• “It has already cost us too much time.”
  

✅ Examples with “Costed” (When Used Technically)

• “The engineers costed the new bridge.”
  
• “We costed each item in the budget proposal.”
  
• “The project was carefully costed to avoid overspending.”
  
• “The team costed the implementation plan thoroughly.”
  
• “The supplier costed the job before bidding.”

Synonyms for “Cost” and “Costed”

Need to mix it up in your writing or speech? Here are some great alternatives.

🔸 Synonyms for “Cost” (General Use)

🔸 Synonyms for “Costed” (Professional Use)

Etymology of “Cost”

Want to know where the word “cost” comes from?

“Cost” traces its origin to the Latin word “constare”—meaning “to stand firm or to be fixed in value.” Over time, it made its way through Old French (“coste”) into Middle English as “costen.”

Originally, it referred to a fixed amount—a price that something stood at. This explains why it eventually took on meanings in finance, sacrifice, and value.

Interestingly, this background gives insight into why “cost” can feel rigid or unchanging—which may be why its past tense remains “cost.”

The emergence of “costed” came later, especially in professional settings, to indicate a conscious act of estimating rather than a simple transaction.

Conclusion: Choose the Right Form with Confidence

In conclusion, understanding the correct usage of “cost” vs. “costed” is essential for clear and accurate communication. The word “cost” is the standard past tense when talking about price or value, like “The shoes cost me $80.” On the other hand, “costed” is only correct in technical or accounting contexts, where it means to calculate the cost of something.

Remember, English has many irregular verbs, and “cost” is one of them. Getting the tense right not only improves your grammar but also shows your command of professional and precise language. Whether you’re writing an email, a report, or just speaking casually, using the correct past tense of “cost” makes all the difference.

So the next time you’re unsure, ask yourself: Am I talking about price or calculation? If it’s price, go with “cost.” If it’s a business process, “costed” might be right. With this simple tip, you’ll never second-guess yourself again.

FQAs

1. What is correct: cost or costed?

 Both are correct, but they’re used differently. Use “cost” for general past tense and “costed” in accounting or pricing analysis.

2. Do you say it cost me or it costed me?

 The correct phrase is “it cost me.” “Costed” is wrong in this sentence because you’re talking about the price, not a calculation.

3. Why is it cost and not costed?

 “Cost” is an irregular verb, so it doesn’t follow the regular “-ed” past tense rule. That’s why we don’t say “costed” in everyday situations.

4. Do we say it cost or it costs?

 Use “it cost” for the past tense and “it costs” for the present tense. For example: “Yesterday, it cost $20” vs. “Today, it costs $25.”

5. Is it correct to say costs?

Yes, “costs” is correct in the present tense with a third-person subject. Example: “This phone costs too much.”

Ruby Skye