CPC stands for cost per click. It is the amount an advertiser pays when a person clicks an ad, whether that ad appears in Google search results, on a shopping listing, in a social feed or on a partner website.
You will meet CPC in two forms. Average CPC is a report metric: total spend divided by total clicks over a period. Maximum CPC is a setting: the most you are willing to pay for a single click on a keyword or ad group. The two are related but rarely equal, because most auctions charge less than the maximum.
A click that leads to a booked emergency repair is worth far more than a click on a comparison article, so CPC only makes sense next to a conversion rate and a value per sale.
Mechanics
How the ad auction sets your CPC
On search platforms the price of a click comes out of an auction that runs every time someone types a query. Each advertiser enters with a bid and a quality signal, and the platform ranks them by the combination. You then pay roughly what is needed to hold your position above the next advertiser, not your full maximum bid.
Three things move the number. Competition: more advertisers bidding on the same words push the clearing price up. Relevance: a higher Quality Score lets you win the same position with a lower bid. Targeting: broad match keywords, wide locations and all-day schedules pull in clicks that look inexpensive but rarely turn into a call.
On social platforms there is no keyword, so the auction weighs your bid against how likely the audience is to react to your creative. Weak creative earns fewer clicks per thousand views, which drives the per-click price up even if the bid stays put.
Example
A worked example for a plumbing company
Assume a plumber runs a search campaign for water heater repair. Over one month the ads collect 40,000 impressions and 1,200 clicks, and the total spend is 3,600. Average CPC is 3,600 divided by 1,200, which is 3.00 per click.
Now add the rest of the funnel. Say 6 percent of those clicks turn into a phone call, so 72 calls. The office books half of them, which gives 36 jobs. The cost per booked job is 3,600 divided by 36, which is 100. If an average repair brings in revenue of 450, the campaign pays 100 to earn 450, and a CPC of 3.00 was reasonable.
Run the same numbers with a 2 percent call rate. The result is 24 calls, 12 jobs and a cost per job of 300 at the very same click price. The CPC did not change, but the economics did.
Use
When CPC helps and when it misleads
- Use CPC to compare keywords, ad groups and match types inside one campaign, where the value of a click is roughly the same across the things you compare.
- Use it to spot sudden shifts: a click price that doubles in a week usually means a new competitor, a broken Quality Score or a change in match type.
- It misleads when you compare channels with different intent, such as a search click for an emergency repair against a social click on a how-to video.
- It misleads as a target on its own, because the lowest priced clicks often come from the least qualified searches, and a low CPC with no calls is money spent for nothing.
- Judge CPC together with CPA and return on ad spend, and read why Google Ads is not working before cutting bids.
Watch out
Common mistakes with CPC
- Setting a maximum CPC based on what feels affordable instead of working backward through conversion rate and the value of a customer.
- Celebrating a falling average CPC while the search terms report fills with irrelevant queries that will never turn into a booking.
- Lowering bids across the whole account instead of trimming the specific keywords and locations that produce expensive clicks without calls.
- Judging a search partner or display placement by its click price alone, without checking whether those clicks ever reach the contact page.