(cost ÷ impressions) × 1,000Use delivered cost and delivered impressions to calculate an effective rate.
MEDIA MATH — THREE DIRECTIONS
Cost. Reach. Rate.
Know the missing one.
Calculate CPM, total media cost, or impressions from two known values. Then compare cost per impression and the reach bought by one currency unit.
Open the calculator ↓COST$2,400
÷IMPRESSIONS400,000
× 1,000CPM$6.00
CPM CALCULATOR
Solve the media plan in either direction.
Use values from the same currency, campaign scope, reporting period, and impression definition. Changing the display currency does not perform foreign exchange.
ONE RELATIONSHIP
Rearrange it for the planning question.
(CPM × impressions) ÷ 1,000Price a planned flight or publisher package at a quoted CPM.
(cost ÷ CPM) × 1,000Estimate how many impressions a budget can buy at a planned rate.
PORTFOLIO CPM
Never average the rate column.
Combine line items by adding cost and impressions first. A tiny expensive placement should not carry the same weight as a large inexpensive one.
LINE A$500 / 100K = $5 CPM
LINE B$100 / 10K = $10 CPM
≠WRONG AVERAGE($5 + $10) / 2 = $7.50
→WEIGHTED RESULT$600 / 110K × 1,000 = $5.45
LABEL THE DENOMINATOR
Not every “impression” is the same event.
Ad-server delivery
Useful for billing and platform operations, but some served ads may never become meaningfully viewable.
Qualified viewability event
Use the qualifying viewable-impression count consistently; do not compare it with a served CPM without labeling the difference.
Effective normalized rate
Publishers often use effective CPM to normalize earned revenue across pricing models. Define the included revenue and impressions.
People versus deliveries
One person can receive several impressions. Frequency connects total impressions to unique reach.
USE CPM WITH AN OUTCOME
The rate needs a second question.
CPM describes exposure economics. Pair it with the signal that matches the campaign job.
Was the exposure qualified?
Read CPM with viewability, on-target reach, frequency, completion, attention, or lift—not clicks alone.
Did exposure earn a visit?
Add CTR and landing-page sessions. Effective CPC can be derived as cost ÷ clicks.
Did the visit become value?
Add conversion rate, CPA, revenue, margin, incrementality, refunds, and attribution assumptions.
CPM ANSWERS
Use the number correctly.
What does CPM stand for?+
Cost per mille—cost per one thousand impressions. “Mille” means thousand. A $6 CPM means one thousand impressions cost six units of the selected currency.
Can I calculate impressions from budget and CPM?+
Yes: impressions = cost ÷ CPM × 1,000. The result is a planning estimate if CPM is only a forecast; auction delivery can vary.
Why can’t CPM be zero?+
A zero CPM cannot be used as a divisor to estimate impressions. Zero cost with delivered impressions produces a zero effective CPM, but enter values that reflect the actual planning question.
Does changing currency convert the values?+
No. The selector changes formatting only. Use cost and CPM expressed in the same currency; perform exchange-rate conversion separately with the relevant date and rate source.
What is a good CPM?+
There is no universal threshold. Audience, country, inventory, format, season, objective, auction, viewability, and measurement all change the rate. Compare like-for-like segments and downstream value.
FROM MATH TO CONTROL