CPM vs CPC vs CPA is a choice about what you pay for. CPM is the cost per 1,000 impressions, CPC is the cost per click, and CPA is the cost per action such as a sale or sign-up. CPL (cost per lead) and CPV (cost per view) are close cousins used for lead generation and video.
None of them is always cheaper. The same campaign can cost $7.50 per sale on a CPM deal and $5.00 on a CPC deal, or the other way round, depending on click-through and conversion rates. This guide gives the formula for each model, when to buy on it, how to convert one into another, and a worked example that shows which offer wins.
Key takeaways
- CPM = (cost ÷ impressions) × 1,000. CPC = cost ÷ clicks. CPA = cost ÷ actions. CPL = cost ÷ leads. CPV = cost ÷ views.
- The models are linked: CPM = CPC × CTR × 1,000, and CPA = CPC ÷ conversion rate.
- The further down the funnel you pay, the more risk the seller carries, and the higher the unit price.
- Buy CPM for reach, CPC for traffic, CPV for video attention, CPA or CPL for results.
- Compare offers by converting everything to the same unit, usually effective CPA.
What is the difference between CPM, CPC and CPA?
CPM charges for every 1,000 times an ad is shown, whether or not anyone acts. CPC charges only when someone clicks. CPA charges only when someone completes an action you define, such as a purchase. As you move from CPM to CPC to CPA, risk shifts from the advertiser to the platform or publisher, and unit prices rise to match.
| Model | You pay for | Formula | Who carries the risk | Best for |
|---|---|---|---|---|
| CPM | 1,000 impressions | (Cost ÷ Impressions) × 1,000 | Advertiser | Awareness, reach, frequency |
| CPC | A click | Cost ÷ Clicks | Shared | Website traffic, search |
| CPA | An action (sale, sign-up, install) | Cost ÷ Actions | Seller or platform | Sales, installs, bookings |
| CPL | A lead (form fill, call) | Cost ÷ Leads | Seller or platform | B2B, education, real estate, auto |
| CPV | A video view (as defined by the platform) | Cost ÷ Views | Shared | Video consideration, storytelling |
Each term has a short definition in our digital media planning glossary, which also covers relatives like vCPM, eCPM and ROAS.
What is CPM and when should you buy on it?
CPM, or cost per mille, is the price of 1,000 ad impressions. It is calculated as total cost divided by impressions, multiplied by 1,000. Buy on CPM when your goal is reach or awareness, when you want to control frequency, and when you trust the ad to work without a click, as with video and brand campaigns.
Formula: CPM = (Cost ÷ Impressions) × 1,000
Example: you spend $720 and get 480,000 impressions. CPM = ($720 ÷ 480,000) × 1,000 = $1.50. In a pricier market, $750 for 100,000 impressions is a $7.50 CPM.
A variant worth knowing is viewable CPM (vCPM), where you pay only for impressions measured as viewable. Google counts a display ad as viewable when 50% of it is on screen for at least one second, and a video when it plays for two seconds, per its viewable CPM help page. vCPM prices are higher because every impression you pay for had a chance to be seen.
CPM is the natural unit for reach planning, as covered in our guide to reach vs frequency.
What is CPC and when should you buy on it?
CPC, or cost per click, is total cost divided by the number of clicks. Buy on CPC when you need people to reach a website or app, as with search ads, and when you are not sure how well an ad will get clicked, because the seller absorbs the cost of impressions that do not earn a click.
Formula: CPC = Cost ÷ Clicks
Example: $600 buys 5,000 clicks. CPC = $0.12. Search advertising runs almost entirely on CPC auctions, because a click on a search ad is a strong intent signal.
A click is not a customer. Always judge CPC together with landing page conversion rate.
What is CPA and when should you buy on it?
CPA, or cost per action or acquisition, is total cost divided by the number of conversions, such as purchases or sign-ups. Use it as your main target when you sell online and track conversions reliably. Your maximum CPA should come from profit per sale, not from benchmarks, or you can hit your target and still lose money.
Formula: CPA = Cost ÷ Conversions
Formula: Break-even CPA = Average order value × Gross margin %
Example: your average order is $30 with a 40% gross margin. Break-even CPA = $12. If repeat customers are worth more over a year, you can justify a higher CPA, but decide that on purpose.
Know the difference between optimising for CPA and paying per action. With Google’s Target CPA bidding, the system sets bids to hit your CPA goal, but you are still charged for clicks. Google notes that Display campaigns can offer a pay-for-conversions option. Most social and programmatic buys are billed on impressions even when the algorithm optimises for purchases. True pay-per-action deals are mostly found in affiliate and performance networks.
What is CPL and how is it different from CPA?
CPL, or cost per lead, is total cost divided by leads, where a lead is a person who shares contact details through a form, call or chat. It is a type of CPA used when the sale happens later, offline or through a sales team. The number that matters most is cost per qualified lead, not raw CPL.
Formula: CPL = Cost ÷ Leads
Formula: Cost per qualified lead = CPL ÷ Qualification rate
Example: a mid-size SUV brand spends $4,500 and gets 1,500 test drive enquiries, a CPL of $3.00. Only 25% are reachable and genuinely in the market. Cost per qualified lead = $3.00 ÷ 0.25 = $12.00. A second campaign at $4.80 CPL with 60% qualification works out to $8.00 per qualified lead, which is cheaper where it counts.
What is CPV and what counts as a view?
CPV, or cost per view, is total cost divided by video views. What counts as a view depends on the platform. On YouTube in-stream ads, a view is counted after 30 seconds, the full ad if shorter, or an interaction. Buy on CPV when you want engaged video watching, not just impressions, and compare platforms carefully because definitions differ.
Formula: CPV = Cost ÷ Views
According to Google Ads Help on CPV bidding, a YouTube in-stream view counts at 30 seconds (or the end of a shorter ad) or on interaction, an in-feed view counts when someone clicks the thumbnail or watches 10 seconds of autoplay, and a Shorts view counts at 10 seconds or a click on the call to action. Bumper and non-skippable ads do not earn views and are typically bought on CPM. Meta’s comparable metric, ThruPlay, counts plays to completion or at least 15 seconds.
Example: $1,000 buys 100,000 YouTube views at a CPV of $0.01. Because a 30-second view is a stronger signal than a 2-second impression, compare CPV only with CPV from the same definition.
How do you convert between CPM, CPC, CPA and CPV?
The models connect through click-through rate (CTR), conversion rate (CVR) and view rate. CPM = CPC × CTR × 1,000. CPC = CPA × CVR. CPA = CPM ÷ (CTR × CVR × 1,000). CPV = CPM ÷ (view rate × 1,000). Converting every offer to the same unit, usually effective CPA, is how you compare deals fairly.
Formula: eCPM = CPC × CTR × 1,000
Formula: Effective CPC = CPM ÷ (CTR × 1,000)
Formula: Effective CPA = CPC ÷ CVR = CPM ÷ (CTR × CVR × 1,000)
Formula: Effective CPV = CPM ÷ (View rate × 1,000)
eCPM is what a non-CPM buy works out to per 1,000 impressions. Example: a CPC of $0.25 at a 0.8% CTR gives an eCPM of $0.25 × 0.008 × 1,000 = $2.00.
Worked example: which pricing offer is actually cheapest?
Convert each offer to effective CPA using your expected CTR and conversion rate. At a 1.2% CTR and 2% conversion rate, a $1.80 CPM works out to $7.50 per sale, a $0.10 CPC to $5.00, and a $7.00 CPA to $7.00. The CPC offer wins, but only while CTR stays below the break-even of 1.8%.
Example setup: a publisher offers three ways to buy the same inventory for a skincare brand. Your past campaigns suggest a 1.2% CTR and a 2% conversion rate from click to purchase.
| Offer | Price | Effective CPM | Effective CPC | Effective CPA |
|---|---|---|---|---|
| CPM deal | $1.80 CPM | $1.80 | $1.80 ÷ 12 = $0.15 | $0.15 ÷ 0.02 = $7.50 |
| CPC deal | $0.10 CPC | $0.10 × 12 = $1.20 | $0.10 | $0.10 ÷ 0.02 = $5.00 |
| CPA deal | $7.00 CPA | $7.00 × 0.02 × 12 = $1.68 | $7.00 × 0.02 = $0.14 | $7.00 |
(12 is CTR × 1,000, the number of clicks per 1,000 impressions at a 1.2% CTR.)
At these rates the CPC deal is cheapest. But the answer flips with performance. The break-even CTR between the CPM and CPC offers is:
Formula: Break-even CTR = CPM ÷ (CPC × 1,000) = $1.80 ÷ $100 = 1.8%
If your creative earns a 2.5% CTR, the CPM deal works out to $0.072 per click and $3.60 per sale, beating both others. Decision rule: if you expect to beat the seller’s assumed CTR, buy CPM; if you are unsure, buy CPC or CPA and let the seller carry the risk. The seller does the same maths, so a CPA price will usually include a margin for that risk.
Which pricing model should you use for your goal?
Match the model to the objective. Use CPM or vCPM for awareness and reach, CPV for video consideration, CPC for traffic and search, and CPA or CPL for sales and leads when tracking is reliable. In a full funnel plan you will use several models at once, each judged by its own KPI.
| Objective | Buy on | Judge by | Watch out for |
|---|---|---|---|
| Awareness and reach | CPM or vCPM | Cost per 1,000 reached, frequency | Cheap CPM with poor viewability |
| Video consideration | CPV | Cost per view, view rate | Different view definitions |
| Traffic | CPC | CPC and landing page conversion | Low-quality clicks |
| Sales | CPA target (billed per click or impression) | CPA vs break-even CPA | Retargeting taking credit |
| Leads | CPL | Cost per qualified lead | Junk form fills |
When you set out a plan with several lines, write the buying model and KPI next to each one, as in our template on how to create a media plan. For CPM lines, add a frequency goal too; our guide to effective frequency explains how to pick one.
What are the most common mistakes with CPM, CPC and CPA?
The common mistakes are comparing CPMs across platforms without checking viewability or audience, chasing the lowest CPC regardless of conversion, setting a CPA target without knowing break-even, judging lead campaigns on raw CPL, and comparing CPVs that use different view definitions. Each one rewards cheap activity instead of real results.
- A $0.50 CPM on low-attention placements can cost more per person truly reached than $2.50 on full-screen video.
- A $0.05 click that never buys costs more than a $0.20 click that does.
- A 2-second view and a 30-second view are not the same product.
What this means for marketers and creators
For marketers and media planners
- Put effective CPA on every line of your weekly report, even for CPM buys, so channels are compared on one scale.
- Before accepting a CPM deal, calculate the break-even CTR. If your creative clears it with room to spare, CPM is the better buy.
- For lead campaigns, pass qualification data back to the platform so it optimises for good leads, not cheap ones.
For creators and small teams
- Brands will quote your rate as an effective CPM or CPV. Know yours: fee ÷ average views × 1,000.
- Example: $360 for a Reel averaging 150,000 views is a $2.40 effective CPM. Compare that to what the brand pays for paid social.
- Offer performance add-ons (a bonus per sale via a tracked link) to share risk and earn more when your audience converts.
Frequently asked questions
Which is better, CPM or CPC?
Neither is better in general. CPM is better when your goal is reach or awareness, or when you expect a click-through rate above the break-even rate, which is CPM divided by CPC times 1,000. CPC is better for traffic goals and when you are unsure how well your ads will be clicked.
How do you calculate CPM?
Divide total cost by total impressions and multiply by 1,000. Example: $720 for 480,000 impressions gives a CPM of $1.50. To find impressions from a budget, reverse it: impressions equal budget divided by CPM, multiplied by 1,000. So $1,200 at a $1.50 CPM buys 800,000 impressions.
What is eCPM and how is it calculated?
eCPM, or effective cost per mille, is what any non-CPM buy works out to per 1,000 impressions. Calculate it as total cost divided by impressions times 1,000, or from CPC as CPC times CTR times 1,000. A $0.25 CPC at a 0.8% click-through rate equals an eCPM of $2.00.
Is CPA the same as CPL?
CPL is a type of CPA. CPA covers any defined action, such as a purchase, install or sign-up. CPL is used when the action is a lead, meaning someone shares contact details for follow-up. Because leads vary in quality, track cost per qualified lead alongside raw CPL to judge campaigns fairly.
What is a good CPA?
A good CPA is one below your break-even CPA, which is average order value multiplied by gross margin. If an order averages $30 at a 40% margin, break-even is $12. Industry averages are a poor guide because margins, prices and repeat purchase rates differ between businesses.
Why does CPA go up?
CPA rises when CPM rises, click-through rate falls or conversion rate falls, since CPA equals CPM divided by the product of CTR, conversion rate and 1,000. Check each in turn: auction competition and seasonality push CPM, creative fatigue cuts CTR, and landing page, price or stock issues cut conversion rate.
Next steps
Run your own numbers with the ad budget and CPA calculator on our free social media tools page, and turn CPM into reach with the reach and frequency calculator. Join the free TechMachaw newsletter for one practical media planning guide every week.
