CPM Calculator
Enter any two of ad cost, impressions and CPM to get the third. Switch to campaign metrics to turn spend, impressions, clicks, conversions and revenue into CPC, CTR, conversion rate, cost per acquisition, ROAS, ROI and frequency, or plan what a budget should deliver before you launch.
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How to use it
- Choose what to work out: CPM, cost or impressions, all campaign metrics, or a budget plan.
- Pick your currency and type the numbers from your ads report. Commas and dots both work.
- To find CPM, ad cost or impressions, choose the one you want and enter the other two.
- Read the main result at the top and the full table of metrics with the formula for each.
Why use this tool
Solve any of three
Find CPM from cost and impressions, the cost of a CPM deal, or how many impressions a budget buys.
Every key metric
CPM, CPC, CTR, conversion rate, CPA, ROAS, ROI, average order value and frequency from one set of numbers.
Break-even ROAS
Add your profit margin to see the ROAS you need to break even and the real profit after product costs.
Budget planner
Turn a budget, an expected CPM, CTR and conversion rate into impressions, clicks, sales and revenue.
Any currency
Works with dollars, euros, yen, rupees and 30 other currencies, with numbers typed in your own format.
Private
Everything is worked out in your browser. Your campaign numbers are never sent or saved.
What is CPM?
CPM means cost per mille, the price of 1,000 ad impressions. It is how most display, video and social ads are priced and the easiest way to compare the cost of reaching people on different platforms.
CPM = ad cost ÷ impressions × 1,000. If a campaign costs $500 and gets 100,000 impressions, the CPM is $500 ÷ 100,000 × 1,000 = $5. Turned around, ad cost = CPM × impressions ÷ 1,000, and impressions = ad cost ÷ CPM × 1,000.
Ad metrics formulas
These are the standard formulas used by Google Ads, Meta, TikTok and most ad platforms. The example uses $500 spend, 100,000 impressions, 1,200 clicks, 36 sales and $2,400 revenue.
| Metric | Formula | Example |
|---|---|---|
| CPM | Spend ÷ impressions × 1,000 | $5.00 |
| CTR | Clicks ÷ impressions × 100 | 1.2% |
| CPC | Spend ÷ clicks | $0.42 |
| Conversion rate | Conversions ÷ clicks × 100 | 3% |
| CPA | Spend ÷ conversions | $13.89 |
| ROAS | Revenue ÷ spend | 4.8× (480%) |
| ROI | (Revenue − spend) ÷ spend × 100 | 380% |
| Frequency | Impressions ÷ reach | 2.5 for 40,000 people |
How CPM, CPC and CTR fit together
The three are linked: CPC = CPM ÷ (CTR × 10) when CTR is in percent. A $5 CPM with a 1% CTR gives a $0.50 CPC. Double the CTR to 2% and the same CPM gives a $0.25 CPC.
That is why a cheap CPM is not always a good deal. Ads that few people click can cost more per click and per sale than a placement with a higher CPM and a better audience.
What is a good ROAS?
A good ROAS depends on your margin. Break-even ROAS = 1 ÷ profit margin. With a 40% margin you need a ROAS of 2.5× just to cover product costs and ads. With a 25% margin you need 4×. Enter your margin in the calculator to see your own break-even point.
Many online stores aim for about 3× to 4× across a whole account, but lead generation, apps and brand campaigns are judged on CPA and reach instead.
What affects CPM
CPM is set by an auction, so it changes with demand. Expect it to vary by:
- Country and city: audiences in high-income markets cost more.
- Platform and placement: video and premium sites usually cost more than banners.
- Audience: narrow or high-value audiences such as business buyers cost more.
- Season: CPMs often rise in November and December when many advertisers compete.
- Ad quality: ads people engage with are often shown at a lower price.
Frequently asked questions
How do I calculate CPM?
Divide the ad cost by the number of impressions and multiply by 1,000. For example, $250 for 50,000 impressions is a CPM of $5.
What does the M in CPM stand for?
M is the Roman numeral for 1,000 (mille in Latin). CPM is the cost per thousand impressions.
How do I calculate CPC and CTR?
CPC is ad spend divided by clicks. CTR is clicks divided by impressions, times 100. 1,200 clicks from 100,000 impressions is a 1.2% CTR.
How do I calculate ROAS?
Divide the revenue from your ads by the ad spend. $2,400 in sales from $500 of ads is a ROAS of 4.8, often written 4.8× or 480%.
What is the difference between ROAS and ROI?
ROAS compares revenue with ad spend. ROI compares the gain after costs with the cost. A 4.8× ROAS is a 380% ROI on ad spend, before product costs.
What is ad frequency?
The average number of times each person saw your ad: impressions divided by reach. Many advertisers refresh the ad when frequency climbs and results drop.
Is my data sent anywhere?
No. Everything is worked out in your browser. The page only remembers which mode you used last, on this device.
How to read ad metrics and judge a campaign
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