CPM, CPC and CTR calculator
Enter your campaign’s cost, impressions and clicks to see cost per mille (CPM), cost per click (CPC) and click-through rate (CTR) at once. Working backwards, it shows what budget a number of impressions costs, how many impressions a budget buys and how many clicks to expect at a given CTR.
How it is calculated
CPM, CPC and CTR formulas
| Metric | Formula | Example |
|---|---|---|
| CPM (cost per mille) | cost ÷ impressions × 1,000 | $250 ÷ 50,000 × 1,000 = $5.00 |
| CPC (cost per click) | cost ÷ clicks | $250 ÷ 600 = $0.42 |
| CTR (click-through rate) | clicks ÷ impressions × 100 | 600 ÷ 50,000 = 1.2% |
The three are linked: CPM = CPC × CTR × 1,000. In the example $0.4167 × 0.012 × 1,000 = $5.00. So if you double your click-through rate at the same CPM, you halve your cost per click.
CPM: the price of 1,000 impressions
Google Ads defines CPM as the amount you pay for 1,000 impressions. The abbreviation stands for “cost per mille” – M is the Roman numeral for a thousand. For social media and display campaigns billed by impressions it is the key price; search ads are usually paid per click.
CPC: average cost per click
Average CPC is the total cost of your clicks divided by the number of clicks. It can be lower than your maximum CPC bid, because the auction often charges less than the maximum bid.
CTR: click-through rate
The CTR formula is the number of clicks divided by the number of impressions. 5 clicks from 100 impressions is 5%. According to Google, how high a click-through rate should be depends on what you are advertising and on which network – no general benchmark can be drawn from that.
Working backwards: budget, impressions, clicks
- Budget = impressions × CPM ÷ 1,000. 100,000 impressions at an $8 CPM cost $800.
- Impressions = budget ÷ CPM × 1,000. $500 at an $8 CPM buys 62,500 impressions.
- Clicks = impressions × CTR. 20,000 impressions at a 1.5% click-through rate bring 300 clicks – at a $0.80 CPC that is $240 in click cost.
For planning, use the CPM and click-through rate from your own past campaigns. Actual values vary with audience, placement, season and competition in the auction.
Frequently asked questions
What is the CPM formula?
Cost divided by impressions, times 1,000. $250 for 50,000 impressions is a CPM of $5.
How do I calculate impressions from CPM?
Budget divided by CPM, times 1,000. With $500 and a CPM of $8 you get 62,500 impressions.
What is the CTR calculator formula?
Clicks divided by impressions, times 100. 600 clicks from 50,000 impressions is 1.2%. The same formula works for email: clicks divided by delivered or opened emails, depending on which you want as the base.
What is the CPC formula?
Cost divided by the number of clicks. $250 for 600 clicks is about $0.42 per click.
What is the difference between CPM and CPC?
With CPM you pay for impressions (per 1,000), with CPC you pay for clicks. The click-through rate converts one into the other: CPC = CPM ÷ (CTR × 1,000).
What is a good CPM or a good CTR?
There is no universal number – Google Ads explicitly says a good CTR depends on what you are advertising and on the network. What tells you more is comparing against your own campaigns and asking whether the cost comes back through conversions in the end (see the ROAS calculator).
Sources and legal basis
- Google Ads Help: Cost-per-thousand impressions (CPM) – definition
- Google Ads Help: Average cost-per-click (CPC) – total cost ÷ clicks
- Google Ads Help: Clickthrough rate (CTR) – clicks ÷ impressions
As of:
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