CPM, CPC and CTR Calculator

Enter any compatible combination of impressions, clicks, spend, CTR, CPM or CPC — this tool solves the rest and flags any figures that don't agree.

CPM $10 · CPC $0.5 · CTR 2%

Solved metrics
Metric	Value
Impressions	10000
Clicks	200
Spend	$100
CTR	2%
CPM	$10
CPC	$0.5

CPM, CPC and CTR formulas

How this is calculated

CPM = 1000 × spend / impressions | CPC = spend / clicks | CTR% = 100 × clicks / impressions

Impressions, clicks and spend are the three independent quantities — CTR, CPM and CPC are always ratios derived from pairs of them.

Worked example

Spend $100, impressions 10,000, clicks 200: CPM = 1000 × 100 / 10,000 = $10; CPC = 100 / 200 = $0.5; CTR = 100 × 200 / 10,000 = 2%.

Missing-input combinations

Any input set that lets this tool anchor impressions, clicks and spend to real numbers works — direct values, or a mix of ratios (CTR, CPM, CPC) with at least one absolute figure to pin them down. A ratio alone, with nothing absolute to anchor it, is never enough to solve for spend.

Conflicting input detection

Example: spend $100, impressions 10,000 and clicks 200 solve to a $0.50 CPC. If you also enter a CPC of $1, this tool flags it as a discrepancy — supplied $1 vs. solved $0.5 — rather than silently trusting one number over the other.

Actual counts versus forecasts

Observed impressions and clicks are whole numbers; a forecast or planning scenario may be fractional and should be labeled as expected, not treated as an exact historical count.

Conflicting inputs: An inconsistent, over-specified input set is flagged, never silently resolved.
Clicks over impressions: Flagged as a warning (definition mismatch), not an unconditional rejection.

Questions

Which combinations are sufficient to calculate CPC?

CPC = spend ÷ clicks, so any input set that lets this tool solve for both spend and clicks is enough — for example, spend and clicks directly, or impressions with CTR (to get clicks) and CPM (to get spend). Supplying only CTR and CPM without a way to anchor either impressions or spend to a real number is not enough, since CPC needs an absolute spend figure, not just a ratio.

Why do my entered metrics disagree?

Because impressions, clicks and spend are the only truly independent numbers — CTR, CPM and CPC are all ratios derived from them. If you type in a CTR, a CPM and a CPC that don't come from the same underlying impressions/clicks/spend, the numbers are mathematically inconsistent. This tool solves the system from what it can, then flags any supplied value that doesn't match the solved result instead of silently trusting one over another.