Costs · Margins · The business of ecommerce
Most merchants quote a single CAC number pulled from a blog post with no source, when the only figures that hold up are platform pricing tiers and channel engagement rates that are actually published and dated.
Most merchants ask for “the CAC benchmark” as if one number exists for all of ecommerce, and then they act surprised when a vendor blog hands them a figure with no source, no date, and no vertical attached. That number is not a benchmark. It is a guess wearing a benchmark’s clothes. The only things worth calling published CAC benchmarks are the pieces that actually carry a source and a date: platform pricing tiers that set the cost floor of running the store, and channel engagement rates that set the cost of reaching a customer through a given channel. Neither of those is CAC on its own, but both are the only verifiable inputs available, and stacking invented numbers on top of them does not make the total more true.
Every CAC calculation starts with fixed costs, and for a Shopify merchant those costs are published in euros, not estimated. Basic runs €24/mo and is aimed at solo entrepreneurs. Grow runs €69/mo for small operations. Advanced runs €289/mo for stores with global reach. Plus starts at €2,100/mo for complex businesses. These figures were taken from Shopify’s pricing page as loaded on September 5, 2026, and they are the entry point for any merchant trying to work out fully loaded acquisition cost, since platform fees are a fixed cost that gets divided across however many customers a store acquires in a period.
The page also lists a promotional entry: a 3-day free trial followed by €1/month for 3 months. That is not the standing rate and should never be used as the denominator in a CAC calculation, because it understates true platform cost for anyone modeling beyond the first quarter.
Card processing rates are the part of CAC math merchants forget most often, because they show up as a percentage taken off revenue rather than a line item on an invoice. Shopify’s page lists these rates plainly by tier.
| Tier | Monthly price | Card rate |
|---|---|---|
| Basic | €24 /mo | from 2% + €0.25 EUR |
| Grow | €69 /mo | 1.8% + €0.25 EUR |
| Advanced | €289 /mo | 1.6% + €0.25 EUR |
| Plus | from €2,100 /mo | not listed on the public rate table |
The gap between 2% and 1.6% on Basic versus Advanced is not trivial once volume climbs, because it applies to every transaction, not just the marginal one. A merchant deciding whether to upgrade tiers to lower card rates is, in effect, deciding whether the fixed monthly cost of the higher tier pays for itself in reduced per-order fees, and that tradeoff only makes sense once both numbers are on the table together, which is why they belong in the same CAC conversation and not two separate spreadsheets.
Once a customer is acquired, the cost of reaching them again drops sharply if email is working, and Mailchimp’s benchmarks page is one of the few places that publishes vertical-specific engagement numbers with a stated update date. For Business and Finance, the click rate is 31.35% against an unsubscribe rate of 2.78%. Both figures were last updated in December 2023 according to Mailchimp’s own note on the page, so they should be read as a snapshot from that period rather than a live rate.
Mailchimp separately states a general click-through benchmark of 34.23 percent, while noting that the industry a business is in may change that figure, which is Mailchimp’s own way of saying vertical matters more than any single blended number. The same page claims that doubling a campaign’s click-through rate is an achievable target, alongside growing the products a list is exposed to by 20%. Neither of those two figures is a cost per acquisition, but a merchant with a working list is effectively paying close to nothing in incremental acquisition cost for repeat purchases driven through it, which is why email engagement belongs in any serious CAC breakdown even though the metric itself is a rate, not a dollar figure.
Mailchimp’s offer of a free 14-day trial, or a 15% discount for lists holding more than 10,000 contacts, is a platform cost lever the same way Shopify’s tier pricing is. A merchant running a list near that 10,000-contact threshold has a direct incentive to check whether the discount applies before renewing, since it changes the fixed cost side of blended CAC without touching the click or unsubscribe rates on the same page.
The prices above were taken from Shopify’s pricing page as loaded on September 5, 2026, and the engagement rates were taken from Mailchimp’s email marketing benchmarks page as loaded on September 8, 2026, with Mailchimp’s own note that the underlying data was last updated in December 2023.
A merchant who wants a real CAC figure should build it from their own ad spend and order count, then check that figure against the fixed costs shown here rather than against an unsourced number from a blog. Start with the tier and card rate that actually apply to the store today, add the email engagement rate for the closest matching vertical, and treat anything without a named source and a date the same way this article treats it: as not a benchmark at all.
There is no single published CAC figure in the facts checked for this article, and any number quoted without a named source and a date should be treated as unverifiable. What is published are the cost inputs that feed into CAC, such as Shopify's transaction rates of 2% + €0.25 on Basic, 1.8% + €0.25 on Grow, and 1.6% + €0.25 on Advanced, and email engagement rates from Mailchimp. A merchant building their own CAC needs to combine these with their own ad spend and conversion data, which this article does not have.
Yes, because the card processing rate is part of the cost of every sale and it changes by tier. Basic at €24/mo carries a rate from 2% + €0.25 EUR, Grow at €69/mo carries 1.8% + €0.25 EUR, and Advanced at €289/mo carries 1.6% + €0.25 EUR. Plus starts at €2,100/mo for complex businesses and is priced separately from the card rate structure shown on the public page. A merchant on Grow paying 1.8% instead of 2% keeps more margin per order, which lowers the net cost of every acquired customer even if ad spend stays flat.
Email is typically the cheapest repeat-purchase channel once a customer is on a list, so its engagement rates matter for retention-adjusted CAC even though they are not CAC themselves. Mailchimp's Business and Finance vertical shows a 31.35% click rate and a 2.78% unsubscribe rate, both dated to December 2023 on Mailchimp's own benchmarks page. Mailchimp separately states a general benchmark of 34.23 percent and notes that industry can shift that figure, and it also claims that doubling a campaign's click-through rate is a stated possibility on the same page. None of these are cost figures, they are engagement figures a merchant would multiply against list value to estimate blended acquisition cost.
A free trial changes the timing of platform cost but not the total, and merchants sometimes conflate the two. Shopify's page lists a 3-day free trial followed by €1/month for 3 months, which is a promotional entry price rather than the standing Basic rate of €24/mo. Mailchimp separately offers a 14-day free trial or a 15% discount for lists over 10,000 contacts, which affects the platform cost side of CAC math for merchants running large lists. Neither trial offer changes the transaction rates or click rates listed elsewhere on the same pages.
They come from platform pricing pages and marketing benchmark reports that state a date, not from aggregated blog claims. This article draws its numbers from Shopify's pricing page and Mailchimp's industry benchmarks page, both loaded on the dates given in the sources list below. Anyone quoting a CAC figure without naming the page and the date it was read is asking to be trusted on faith, which is the opposite of what a benchmark is supposed to offer.