CPM Calculator

Written byOleh Soloninupdated 25 September 2026

What to calculate

Budget

Impressions

Result

CPM$60.00
Impressions500,000
Budget$30,000.00
Cost of one impression0.06
Impressions per CPM unit1,000

The currency of display advertising

Cost per thousand impressions, or the number of impressions a given budget buys at a given CPM.

CPM is the price of a thousand impressions and the basic unit of display buying. Unlike cost per click, you pay for the ad being shown, whether or not anyone reacts.

The model suits reach objectives: brand awareness, a launch announcement, staying front of mind. For direct response it is riskier — you pay for impressions and whether clicks follow depends entirely on the creative.

How to use

Pick the mode: CPM from budget and impressions, or impressions from a budget and a quoted CPM.
In the first mode, enter the money spent and the impressions delivered.
In the second, enter the budget and the publisher's CPM; the calculator returns the impressions it buys.
Remember that impressions are not reach: one person can see the same ad several times.

What one budget buys

The top half of the table is the “CPM from spend” mode: the budget stays at 30,000 and the impressions change. The bottom half runs it the other way — same budget, but the publisher's CPM is given and the calculator works out the impressions.

Both halves show the same hyperbola from opposite sides. The price of a single impression is the CPM divided by a thousand: 0.06 at a CPM of 60, 0.4 at a CPM of 400.

Runs of this calculator on a budget of 30,000.
Mode	Given	CPM	Impressions	Cost per impression
CPM from spend	100,000 impressions	300	100,000	0.3
CPM from spend	200,000 impressions	150	200,000	0.15
CPM from spend	500,000 impressions	60	500,000	0.06
CPM from spend	1,000,000 impressions	30	1,000,000	0.03
Impressions from CPM	CPM of 80	80	375,000	0.08
Impressions from CPM	CPM of 150	150	200,000	0.15
Impressions from CPM	CPM of 400	400	75,000	0.4

What this calculator shows

CPM from spend and impressions, or impressions from budget and CPM
The cost of a single impression
The budget-to-impressions relationship in both directions

What to keep in mind

An impression is not a view: an ad can count as served while sitting below the fold. Some inventory is sold on viewable impressions, and its CPM is higher.
Reach and impressions differ: one person can see an ad several times, so reach is lower than the impression count.

FAQs

When should I buy on CPM rather than CPC?

When the objective is reach and recall rather than an immediate click. CPM also wins if your creative earns an above-average CTR: you pay for impressions and collect the extra clicks free.

How do impressions differ from reach?

Impressions count every appearance, reach counts unique people. At a frequency of three, reach is a third of the impression count.

What are viewable impressions?

By the MRC standard Google follows, a display ad counts as viewable when at least half of it is on screen for a second or more, a video when half is on screen for two seconds; large display ads need only 30 percent. Buying on viewability means paying only for those, so a thousand of them costs more than a thousand ordinary impressions.

What CPM should I expect?

There is no single norm: CPM depends on the platform, audience, format and period. The figures in the table above are worked examples, not market prices; judge a CPM by what its clicks and leads cost.

Why per thousand rather than per impression?

The M in CPM is the Roman thousand. Pricing a single impression is awkward because the figures get very small: at a CPM of 60 one impression costs 0.06.

How do I turn a CPM into a cost per click?

Divide the CPM by a thousand and then by the click-through rate as a fraction. A CPM of 150 at a 1 percent CTR is a click at 15; at 3 percent, a click at 5.

Worked example

A display campaign

Input: 30,000 budget across 500,000 impressions

Output: CPM 60, one impression costs 0.06

Note: Whether that is a good price is settled not by the market but by what the clicks and leads from those impressions cost: CPM depends on the platform, audience, format and season.

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