CPC vs CPM: which should you buy?
With CPC (cost per click) you pay only when someone clicks your ad. With CPM (cost per mille) you pay for every 1,000 times your ad is shown, whether or not anyone clicks. CPC suits campaigns that need visits, leads or sales; CPM suits awareness, video and reach.
The formulas
- CPC charge = valid clicks × your CPC rate
- CPM charge = impressions ÷ 1,000 × your CPM rate
- Effective CPM of a CPC campaign = CPC × CTR × 1,000
- Effective CPC of a CPM campaign = CPM ÷ (CTR × 1,000)
Example: a CPC of ₹10 with a 1% click-through rate is worth an effective CPM of ₹10 × 0.01 × 1,000 = ₹100.
When to use each
| CPC | CPM | |
|---|---|---|
| You pay for | Valid clicks | Impressions served |
| Best for | Leads, sign-ups, sales, app installs, traffic | Awareness, reach, video, retargeting |
| Risk if the ad is ignored | Low: no clicks, no charge | Higher: you pay for views |
| What to watch | Conversion rate after the click | Click-through rate and reach |
Goals sit on top of the pricing
Whether you buy on CPC or CPM, you can still aim for a business result such as a cost per lead, cost per acquisition or cost per sale / ROAS. On Instant Metric those goals are measured and optimized; you are billed only the agreed CPC or CPM.
Common questions
Is CPC always cheaper than CPM?
Not necessarily. Compare them through effective CPM (CPC × CTR × 1,000). If your ads get a high click-through rate, CPM can work out cheaper per click.
What is a valid click?
A click that passes quality checks: not from a known bot, not a repeated or instant click, and matched to a real ad impression.