CPM vs CPC: which way of paying suits your small ads?

Quick answer

CPM means paying per thousand impressions, so you pay for views. CPC means paying per click, so you pay for visits. CPM suits awareness, retargeting and visual adverts where being seen matters. CPC suits search ads and campaigns built to bring enquiries. Compare both on the cost of the result you want, not the headline rate.

Ad platforms love abbreviations, and CPM and CPC are two of the first a small business owner meets. They sound like technical settings. They are really a choice about what you are buying: the chance to be seen, or a visit to your website. Choosing the wrong one, or comparing them on the wrong number, is one of the most common ways small budgets are wasted.

What each one means

• CPM (cost per mille): you pay for every thousand times your advert is shown. “Mille” is Latin for thousand. Whether anyone clicks makes no difference to the bill.
• CPC (cost per click): you pay only when someone clicks your advert. Being shown is free; the click is what you buy.

Some platforms also offer variations, such as paying per viewable thousand impressions, where an advert must actually appear on screen to count. Google’s help pages explain cost per click and its viewable CPM option.

CPM and CPC compared

The maths, worked through

The only fair way to compare is to turn both into a cost per visit, then a cost per enquiry. Here is an illustrative example with round numbers, not market rates.

• CPM: you pay £5 per thousand impressions. £100 buys 20,000 impressions. If 0.5% of viewers click, that is 100 visits, so each visit cost £1.
• CPC: you pay £0.40 per click. £100 buys 250 visits, so each visit cost £0.40.

In this example, CPC wins on visits. But change one number and the answer flips: if your advert is strong and 2% of viewers click, the same CPM budget buys 400 visits at £0.25 each. That is why the headline rate means nothing on its own. What matters is your advert’s click rate, and then how many visits turn into enquiries.

Take it one step further. If one visit in twenty becomes an enquiry, a £0.40 visit means a £8 enquiry. Compare that with what an enquiry is worth to you. Our guide to measuring marketing return shows how to work out the figure you can afford.

When CPM makes sense

• Retargeting people who have already visited your site, where reminding them is the goal.
• Local awareness, such as a new shop or a seasonal service, where being seen around town is the point.
• Video and visual adverts that work even when nobody clicks.
• Strong creative with a high click rate, which makes views cheap per visit.

When CPC makes sense

• Search adverts, where people are actively looking for what you sell. Google search ads charge per click.
• Enquiry-led campaigns for trades and services, where only visits matter.
• Untested adverts, where you do not yet know the click rate and want to pay only for results.

Our guide to what Google Ads costs explains realistic click prices and budgets for small businesses.

The objective matters more than the billing

On social platforms, the billing method often follows the objective you choose. Meta’s adverts are usually charged per impression, and the platform then shows your advert to the people it predicts will take the action you chose, whether that is a click, a message or a purchase. Meta’s help on ad billing explains how charges are worked out. Choose the objective that matches your goal first; that does more for results than the billing method. Our guide to Facebook and Instagram ads for small businesses covers objectives in detail, and our post on boosting posts versus Ads Manager explains why boosting often buys the wrong thing.

What changes the rate you pay

Neither CPM nor CPC is a fixed price. Both are set by auctions, and the rate you pay depends on several things:

• Competition. More advertisers chasing the same people or searches push prices up. Trades in busy cities pay more per click than the same trade in a quiet market town.
• Audience. Narrow, valuable audiences cost more to reach per thousand than broad ones.
• Season. Retail audiences cost more before Christmas; heating searches cost more when the weather turns cold.
• Advert quality. Platforms reward adverts that people engage with. A relevant, well-made advert can pay less per click or per thousand than a poor one in the same auction. Google calls part of this Quality Score.
• Landing page. On Google, a relevant and fast landing page also helps the price you pay.

This is why copying someone else’s rates is pointless. Run a small test, measure your own click rate and cost per enquiry, and decide from your own numbers.

Testing both fairly

If you want to compare the two methods directly, keep everything else the same: the same advert, the same audience or keywords, the same landing page and a similar budget, for at least two to four weeks. Track enquiries, not just clicks, using the conversion tracking each platform provides. Judge the winner on cost per enquiry, and then on the quality of those enquiries, because a cheap enquiry that never books is not cheap. A test run for three days on a few pounds tells you very little, because the platforms need time and data to settle.

Common mistakes

• Choosing CPM because the headline number looks tiny.
• Judging a campaign on clicks without tracking enquiries.
• Running awareness adverts and expecting immediate sales.
• Running search adverts without negative keywords, so clicks come from the wrong searches.
• Changing billing method every few days before the platform has learned anything.

A worked example

A mobile tyre fitter in Swindon ran two campaigns with the same £300 monthly budget. A Google search campaign on a per-click basis targeted “mobile tyre fitting” searches in his area and brought a steady flow of calls, because every click came from someone who needed a tyre now. A Facebook campaign charged per impression showed a short video of a roadside fit to drivers within fifteen miles. It brought few direct calls, but more people searched for his business name the following month. He kept both, judged the search campaign on cost per call and the social one on reach and brand searches, and stopped comparing their clicks against each other.

The verdict

If people are already searching for what you sell, pay per click on search and judge it on cost per enquiry. If you need people to see you before they need you, or to remind past visitors, pay for views on social or display and judge it on reach and the searches it creates later. Most small businesses with a modest budget should start with search, prove it brings work, then add view-based campaigns once the basics pay.

Getting help

Our Google Ads management is £199 a month and focuses on what each pound of spend brings back, and our Meta ads management is also £199 a month. Ad spend is paid directly to the platforms. All our prices are on the pricing page.