CPM calculator (cost per mille)

This CPM calculator works three ways. Give it what you spent and the impressions you got, and it tells you your CPM. Give it a CPM and some impressions, and it tells you the cost. Or give it a budget and a CPM, and it tells you how many times your ad will be seen.

Then follow the money. Under More options, add your clicks and conversions, or the rates you expect, and it shows what each click and each lead cost. Add a frequency and it estimates how many people you reached.

How to calculate CPM (the CPM formula)

CPM is cost per mille, the price of a thousand impressions. Divide the cost by the impressions and multiply by 1,000. One sum does all three jobs.

The currency makes no difference to the sum. Pick euro, sterling or dollars and the answer comes back in yours.

What is CPM in marketing?

An impression is one showing of your ad on one screen. CPM prices a thousand of them. Nobody has to click.

That makes it the natural measure for ads people see rather than search for. Meta charges most campaigns by impression, so your Facebook and Instagram reports lead with it. Google’s display network and YouTube let you bid for views by the thousand.

Search ads are charged per click. You can still work out their CPM from the cost and the impressions, and it’s a fair way to compare channels side by side.

What CPM can’t tell you is who saw the ad. A cheap thousand impressions in front of people who will never buy is dearer than an expensive thousand in front of people who will.

What’s the difference between CPC, CPM and CPA?

They price the same campaign at three different points.

They are linked by two rates. Click-through rate turns impressions into clicks. Conversion rate turns clicks into results. Cost per click = CPM ÷ (CTR × 10), with CTR as a percentage, so a €4 CPM at a 1% click-through rate is 40 cent a click.

Lift the rate to 2% and the same CPM gives you 20 cent a click. That’s why a better ad often does more for your costs than a cheaper audience. It lowers the price of every click without touching the CPM.

Should I use CPM or CPC?

Pay by impression when you want to be seen: a launch, an event, a local audience you want to remember your name. Pay by click when you want visits, and let the platform find the people likely to click.

Whichever you buy, judge it on CPA. Cheap impressions and cheap clicks both look good in a report and cost you money if nobody buys. The ROAS calculator tells you whether they paid for themselves.

Reach and frequency in the CPM calculator

Impressions count showings, not people. If each person sees your ad three times, 125,000 impressions reached about 42,000 people. Meta reports frequency for every campaign; put it under More options and the calculator does the division.

Watch it climb. Once the same people have seen an ad five or six times, reactions fall and the price rises. Fresh creative every few weeks keeps both in check.

What makes CPM go up or down

You are bidding against every advertiser who wants the same people. A small audience that everyone wants, like business owners in one county, costs more per thousand. So does a busy season. Black Friday. Christmas.

A weak ad costs more too, because the platforms charge more to show ads people scroll past.

And sometimes everybody’s prices rise at once. In the second quarter of 2026, Meta reported that the average price per ad rose 12% on a year earlier, while the impressions it delivered rose 14%. More people are seeing ads. Each showing costs more.

How to lower your CPM

Start with the ad, not the budget. Ads people stop for are cheaper to show, on every platform.

Then look at the audience. Very narrow targeting often costs more per thousand than a broader audience the platform can find buyers in. Test both.

For what shapes the price in Ireland, read our Facebook ads cost guide and our Instagram ads cost guide. Or hand it over: we run the campaigns.