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CPM, reach, impressions and frequency calculator

Turn budget into impressions, estimate reach from frequency, find a campaign's CPM or the budget needed for a reach goal.

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CPM and reach calculator

What do you want to calculate
How much will be spent on ads in the campaign.
How much you pay for every thousand impressions delivered.
Leave blank to skip the click and CPC estimate.

Result

Impressions
200,000
Budget
$5,000.00
CPM
$25.00
Estimated clicks
3,000
Estimated CPC
$1.67

Rounding: impressions and reach round down, budget rounds up, CPM and CPC to the nearest cent.

How to calculate impressions, reach and CPM

CPM, impressions, reach and frequency are four ways of counting the same ad delivery, and almost every upper-funnel media plan runs through them. This calculator links the numbers: budget and CPM give impressions; an assumed frequency gives estimated reach; and if you have a target number of people, it returns the budget you need.

Reach here is always an estimate. Only the platform knows how many unique people saw the ad, and its number can differ from what the frequency math suggests.

  1. Choose what to calculate. Pick impressions (budget and CPM), reach (budget, CPM and frequency), CPM (impressions and cost) or budget needed (reach goal, frequency and CPM).
  2. Fill in the fields for that mode. Type the values in your language's format, for example 5,000.00. CPM is the cost of a thousand impressions, not of one.
  3. Enter the frequency when the mode asks for it. It is how many times, on average, each person sees the ad. It must be 1 or more, since nobody is reached without seeing the ad at least once.
  4. Add the CTR if you want. With the click-through rate you also get estimated clicks and CPC. Leave it blank to skip.
  5. Read the result and the notes. The highlighted figure changes with the mode. The notes remind you that reach is an estimate and explain the rounding.

Everything is calculated here, in your browser. Nothing you type is sent to any server and we use no third-party cookies.

How the math works

Everything is calculated with whole numbers: money in cents, CPM in cents per thousand impressions and frequency in hundredths. That avoids floating-point decimal errors. Impressions and reach round down, because you only count what was actually delivered, and budget rounds up, because the budget must cover the goal. CPM and CPC round to the nearest cent.

Frequency is the ratio of impressions to reach. That is why, to estimate reach from impressions, the calculator divides by the frequency you assumed. If real frequency is higher, real reach will be lower, and the reverse also holds.

  • Impressionsbudget ÷ CPM × 1,000
  • Estimated reachimpressions ÷ frequency
  • CPMcost ÷ impressions × 1,000
  • Budget neededreach × frequency ÷ 1,000 × CPM
  • Estimated clicksimpressions × CTR
  • CPCbudget ÷ clicks

Examples

From budget to people reached

With $5,000.00 and a $25.00 CPM, the campaign delivers 200,000 impressions. If each person sees the ad 2.5 times on average, estimated reach is 80,000 people.

Budget for a reach goal

To reach 200,000 people at a frequency of 2.5 and a $25.00 CPM, you need 500,000 impressions and a budget of $12,500.00.

CPM and CPC of a measured campaign

A campaign cost $25,000.00 to deliver 1,000,000 impressions, which is a $25.00 CPM. With a 1.5% CTR that is 15,000 clicks and a CPC of $1.67.

Frequently asked questions

What is CPM?

CPM is the cost per thousand impressions: what you pay for the ad to be shown a thousand times. If a campaign cost $500.00 and had 20,000 impressions, the CPM is $25.00. The math is cost divided by impressions, times a thousand.

What is the difference between reach and impressions?

Reach counts different people who saw the ad; impressions count every showing, including repeats to the same person. That is why impressions are always equal to or higher than reach.

What is frequency in advertising?

Frequency is the average number of times each reached person saw the ad, that is, impressions divided by reach. With 200,000 impressions and 80,000 people, frequency is 2.5.

What is the ideal frequency?

There is no magic number: it depends on the goal, the audience, the offer and the creative. In general, very low frequency has little recall effect and very high frequency tires the audience, so track creative performance as frequency rises and test variations.

Is the calculated reach the platform's real reach?

No, it is an estimate based on the frequency you assumed. Real reach depends on overlap between ads and audiences, and only the platform measures it. Use the math to plan, then check the platform report.

Why does CPM vary so much between campaigns?

Because ads are sold in an auction: CPM moves with competition for the chosen audience, placement, time of year, creative quality and campaign objective. Past CPM is a reference, not a guarantee.

How do CPM, CPC and CPA relate?

CPM is the cost per thousand impressions, CPC is the cost per click and CPA is the cost per acquisition. Each comes from the previous one through a rate: CPC = CPM ÷ (1,000 × CTR), and CPA = CPC ÷ the click-to-sale conversion rate.

Can I calculate CPC with this tool?

Yes, enter the CTR and the calculator estimates clicks and CPC. If CTR is zero there are no estimated clicks and CPC does not exist, so it shows as n/a.

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