Free tool Ad metrics calculator
Ad reports give you four raw numbers: spend, impressions, clicks and conversions. Enter what you have and the calculator returns CPM, CPC, CTR, conversion rate and cost per acquisition, so every channel can be read on the same line.
- Five metrics at once
- Updates as you type
- Runs locally
Turn raw ad numbers into metrics
Every box is optional. Each metric appears as soon as the two numbers it needs are filled in.
Total spend for the period, in your currency.
How many times the ads were shown.
Link clicks from the same report.
Purchases, sign-ups or leads, whatever you count as the goal.
CPA (cost per acquisition)
$20.00
Spend divided by conversions.
Share these inputs: the values go after the # in the link, so they never reach a server.
https://tapcub.com/tools/ad-metrics-calculator
Version v1.0Updated Update history
Five numbers, one chain
Each metric covers one step from impression to customer. Read them in order to find where a channel gets expensive.
CPA
What one conversion cost. This is the number to compare channels on, and the one to hold against what a customer is worth.
CPM and CTR
CPM is the price of attention; CTR is how much of that attention the ad converts into clicks. Cheap CPM with a weak CTR still gives expensive clicks.
CPC
The price of one visit. It equals CPM ÷ (1,000 × CTR), so it falls when the ad gets better, not only when the auction gets cheaper.
Conversion rate
The share of clicks that converted. This is the landing page and offer at work. CPA = CPC ÷ conversion rate.
If conversions exceed clicks (view-through or offline conversions are included) the conversion rate is left blank; if clicks exceed impressions, CTR is left blank. Both mean the numbers come from different definitions.
Three ways to use the calculator
Fill in what the report gives you; the rest follows.
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1
Read one campaign
Copy spend, impressions, clicks and conversions from the ad report to see the full chain.
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2
Compare channels
Run each channel with the same date range. Find the step where one channel falls behind: price, ad or landing page.
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3
Check a partial report
Only have spend and conversions? Enter those two and read CPA; the other metrics wait for their inputs.
Five ratios from four numbers
All five metrics are simple divisions. They also chain together, which is how you can tell which step moved when CPA changes.
- CPC = CPM ÷ (1,000 × CTR): $4.00 ÷ (1,000 × 0.8%) = $0.50
- CPA = CPC ÷ conversion rate: $0.50 ÷ 2.5% = $20.00
- Use all four numbers from the same report and date range
CPM
CPM = spend ÷ impressions × 1,000
$6,000 on 1,500,000 impressions → $4.00
CTR and CPC
CTR = clicks ÷ impressions · CPC = spend ÷ clicks
12,000 clicks → CTR 0.80%, CPC $0.50
Conversion rate
conversion rate = conversions ÷ clicks
300 conversions from 12,000 clicks → 2.50%
CPA
CPA = spend ÷ conversions
$6,000 ÷ 300 → $20.00
Three channels, $2,000 each
The same budget on search, a social feed and a display network. Each wins on a different metric; only one wins on CPA.
| Channel | CPM | CTR | CPC | Conversion rate | CPA |
|---|---|---|---|---|---|
| Paid search | $20.00 | 4.00% | $0.50 | 3.00% | $16.67 |
| Social feed | $4.00 | 1.00% | $0.40 | 1.50% | $26.67 |
| Display network | $2.00 | 0.20% | $1.00 | 1.00% | $100.00 |
Inputs: search 100,000 impressions, 4,000 clicks, 120 conversions; social 500,000, 5,000, 75; display 1,000,000, 2,000, 20. Display has the cheapest CPM and the most expensive customers; the social feed has the cheapest clicks; search has the cheapest conversions. Sample figures.
Where ad metrics mislead
Each ratio is correct on its own. The mistakes come from reading one in isolation.
Judging by CPM
Cheap impressions that nobody clicks make expensive customers. Follow the chain down to CPA.
Different conversion definitions
A lead on one channel and a purchase on another give CPAs that cannot be compared. Use the same goal for every row.
Platform-counted conversions
Each platform credits itself, often with view-through. Their CPAs look lower than what you pay per real customer.
Mixed date ranges
Spend this week and conversions from a 30-day window give a CPA that matches no period.
Conversions you can trust in the denominator
Platform reports supply spend and impressions; the conversions are better counted on your own site. TapCub reads UTM parameters and ad click IDs, keeps the source on the visitor, and reports conversions and revenue per campaign.
Campaign and channel reports
Sessions, conversions and conversion rate per campaign, source and medium.
Learn moreChannel ROI
Import spend and see return per channel next to the traffic it bought.
Learn moreFirst and last touch
The campaign that introduced a customer and the one that closed, on the same person.
Learn moreAd metrics questions
Still have a question?
Chat with the team behind TapCub — we usually reply within a few hours on business days.
What do CPM, CPC, CTR and CPA mean?
CPM is cost per thousand impressions, CPC cost per click, CTR click-through rate (clicks ÷ impressions) and CPA cost per acquisition (spend ÷ conversions). Conversion rate is conversions ÷ clicks.
How do I calculate CPA?
Divide ad spend by conversions. $6,000 that produced 300 conversions is a CPA of $20.00. Define the conversion first: a purchase, a sign-up or a qualified lead give very different CPAs.
How do I convert CPM to CPC?
CPC = CPM ÷ (1,000 × CTR). A $4.00 CPM at a 0.8% CTR is $0.50 per click. Going the other way, CPM = CPC × CTR × 1,000.
What is the difference between CPA and CAC?
CPA is the ad cost per conversion of any kind, usually from one channel. CAC is all marketing and sales cost divided by new paying customers. The CAC calculator does the second.
Which metric should I optimise?
The one closest to money that you can measure reliably: usually CPA, or ROAS when order values vary. Use CPM, CTR and conversion rate to find which step to fix. See the ROAS calculator.
Why is the conversion rate blank?
The calculator leaves it empty when conversions are higher than clicks. That happens when the platform counts view-through or offline conversions that never clicked. Use click-through conversions only, or read CPA instead.
Update history
New features, fixes and data refreshes for this tool, newest first.
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· v1.0
LaunchedFirst release.
Missing something or found an error? Tell us — requests that come up often go into the next update. All tool updates
Count conversions once, on your own site
Connect your site and every tagged campaign shows visits, conversions and revenue beside its cost.