PPC Calculator Guide: CPC, CPM, CTR & ROAS Explained
A complete overview of the PPC Calculator — how CPC, CPM, CTR, CPA, and ROAS are each calculated from the same underlying campaign numbers.
Every core PPC metric comes from the same three numbers — ad spend, impressions, and clicks — just divided in different combinations. This calculator runs all of them at once so you never have to remember which formula goes with which metric.
The three core metrics
- CPC (cost per click) = ad spend ÷ clicks. How much a single click actually cost.
- CPM (cost per mille) = (ad spend ÷ impressions) × 1,000. How much it costs to put the ad in front of 1,000 people, regardless of clicks.
- CTR (click-through rate) = (clicks ÷ impressions) × 100. What share of viewers clicked.
The optional conversion metrics
Add conversions and the revenue they generated, and the calculator also works out conversion rate (conversions ÷ clicks), CPA (ad spend ÷ conversions), and ROAS (revenue ÷ ad spend). These answer a different question than the first three — not just what traffic cost, but whether it actually turned into something.
Why CPC and CPM can move in opposite directions
A campaign can have a low CPC but a high CPM (lots of cheap clicks relative to spend, but expensive per-impression pricing because CTR is high), or the reverse (few people click, so each click absorbs a larger share of the impression cost). Looking at only one of the two can hide what's actually driving your cost.
The PPC Calculator calculates all of these instantly from your ad spend, impressions, and clicks.