Calculate Cost Per Click (CPC), click-through rate, and ad campaign efficiency. Understand how much you are paying per click and whether your ads are cost-effective.
One campaign: what you spent and what it produced
Spend and impressions
$
Total amount spent on the campaign.
Total ad impressions (views). Leave at 0 to skip CTR.
What the spend produced
Total number of clicks generated.
Number of conversions from clicks. Leave at 0 to skip.
Cost Per Click (CPC)
$2.00
Average cost for each click on your ad.
Formula verified 12 September 2026
Click-Through Rate (CTR)
1.00%
Percentage of impressions that resulted in a click.
Cost Per Conversion (CPA)
$50.00
Average cost per conversion (purchase, lead, signup).
CPM (Cost per 1,000 Impressions)
$20.00
Cost per 1,000 impressions — useful for brand awareness campaigns.
Click-to-Conversion Rate
4.00%
Share of clicks that converted — the stage after the click, where a landing page either works or does not.
Projected clicks, conversions, and cost per conversion at different ad budgets, using the CPC and click-to-conversion rate implied by your inputs.
Ad budget
Clicks
Conversions
Cost / conversion
$500
250
10
$50
$1,000
500
20
$50
$2,000
1,000
40
$50
$5,000
2,500
100
$50
$10,000
5,000
200
$50
Estimates only — not financial, tax, or professional advice.
100% private — every number you enter is calculated in your browser and never sent to our servers.
What it calculates: Cost Per Click (CPC), Click-Through Rate (CTR), Cost Per Conversion (CPA), CPM (Cost per 1,000 Impressions).
Updated 5 June 2026 · Transparent assumptions
$20 CPM, $2 CPC, $50 per conversion — each stage has its own price
A campaign has three transitions and this reports the price of each. $1,000 buying 50,000 impressions is a $20 CPM, the cost of being seen. 500 clicks from those impressions is a 1% click-through rate and a $2 cost per click, the cost of attention. 20 conversions from 500 clicks is a 4% click-to-conversion rate and $50 per conversion, the cost of a customer.
Reading them together localises the problem. High CPM with a healthy click-through rate means you are buying expensive inventory. A good CPM with a poor click-through rate means the creative or the targeting is wrong. Strong clicks with weak conversion means the ad is writing a cheque the landing page cannot cash. Only the last stage is worth money, but you cannot fix it without knowing which stage leaks.
$50 per conversion is good or ruinous depending on what a customer is worth
Cost per conversion is meaningless in isolation. Against a customer worth $500 in gross profit it is an excellent trade; against one worth $40 it destroys value on every sale. The ceiling is set by unit economics — contribution per customer, and how much of it you are willing to spend to acquire one — not by any industry benchmark.
For a repeat-purchase business the relevant figure is lifetime value rather than first-order profit, which is what lets some businesses pay more than a first sale returns. That only works if the retention assumption holds, and it is where a great many campaigns are justified on an lifetime value figure the business has never actually observed.
You bid, the auction prices, and relevance decides how much you actually pay
Search and social advertising run auctions where the price paid depends on competitors\u2019 bids and on a quality or relevance score. A more relevant ad with a better click-through rate is typically charged less for the same position, so improving creative lowers CPC without touching the bid. That is why the fastest route to a cheaper click is often a better ad rather than a lower bid.
Costs also move with demand. Retail keywords in the fourth quarter, insurance and legal terms year-round, and anything seasonal will price far above the average. A CPC that rose 30% may reflect a competitor entering the auction rather than anything you changed, which is why CPC is a diagnostic to watch alongside cost per conversion rather than a target to minimise on its own.
Last-click attribution gives every conversion to the final ad and none to the rest
The conversions entered here come from an attribution model, and the default in most platforms is last click — full credit to the final touch before purchase. That systematically overstates bottom-of-funnel channels such as branded search and understates awareness spend that started the journey.
It also means platform-reported numbers double-count across platforms: two networks can each claim the same sale. Comparing a platform\u2019s conversion count against actual orders in your own system is the standard sanity check, and the gap is usually large enough to change which campaigns look profitable.
One campaign, one window, and no view-through or organic effect
These ratios describe a single campaign over whatever period you entered. They exclude everything outside the click path: view-through conversions, the lift a campaign gives to organic and direct traffic, and any offline sales it influenced. For brand campaigns in particular, direct-response metrics measure the smallest part of the effect.
Nor do they include the cost of producing the creative, agency fees, or the time to manage the account — real costs that belong in any honest cost per acquisition. A conversion window that is too short will also undercount: for a considered purchase with a long decision cycle, conversions attributed within seven days can be a fraction of the eventual total.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Results are estimates for planning and analysis based on the figures you enter. They are not accounting, tax, or financial advice — verify with your own records and a qualified professional before making decisions.
Published the calculator with its formula, worked example, assumptions, limitations and a bespoke guide, and added an automated formula test suite covering it.
Verified the four campaign ratios against each other — spend, impressions, clicks and conversions must reconcile, so CPM, CPC, click-through and cost per conversion cannot disagree.
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