How is CPM different from CPC?

CPM measures the cost of being seen, regardless of clicks. CPC measures the cost of an actual click, which depends on both CPM and click-through rate together.

What causes CPM to spike?

Increased competition for the same audience (common around holidays), a smaller or more competitive targeting pool, and lower ad relevance scores are the usual drivers.

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Advertising

CPM Calculator

Cost Per Mille (per thousand impressions) is the standard way to compare how efficiently different campaigns or platforms buy reach.

Ad Spend

Impressions

CPM

5.00

What This Means

Cost per 1,000 impressions, the standard way to compare reach efficiency across campaigns or platforms.

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Try the Ad Performance Calculator

The Formula

CPM = (Ad Spend / Impressions) × 1,000

Why It Matters

CPM isolates the cost of reach itself, separate from how well an ad converts once seen, which makes it useful for comparing raw media efficiency across platforms before creative or targeting differences enter the picture. A rising CPM with a flat CTR usually points to audience saturation or seasonal demand, not a creative problem.

Example

A campaign spends $1,500 and generates 300,000 impressions. CPM is ($1,500 divided by 300,000) times 1,000, which equals $5.00.

Frequently Asked Questions

CPM measures the cost of being seen, regardless of clicks. CPC measures the cost of an actual click, which depends on both CPM and click-through rate together.
Increased competition for the same audience (common around holidays), a smaller or more competitive targeting pool, and lower ad relevance scores are the usual drivers.

Related Calculators

CPC Calculator CPA Calculator

From the Glossary

Cost Per Mille (CPM)Click-Through Rate (CTR)

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