Every comparison of these two lines up a price per contact and invites you to read down the column. It is a reasonable thing to want and it produces a misleading answer, because the two platforms do not mean the same thing by the word contact.
One of them bills you per membership, counts people who have asked you to stop emailing them, and will happily count the same person three times. The other bills you once per person and stops the moment that person becomes unreachable. Run one real list through both definitions and the billable record counts can differ by 40 percent before either rate card is consulted.
So this page starts with the unit. Once you can convert your own list between the two definitions, the price question resolves quickly, and you can spend your attention on the handful of differences that are genuinely worth deciding on.
We build and maintain custom HubSpot integrations for a living, so the disclosure belongs up front: we do not sell either of these and we are not trying to talk you out of both. For most teams one of these two is the right answer and the only interesting question is which. The part where we have something to add is narrow, and it is that the integration between your CRM and whichever one you pick is the thing that decides how many billable records exist.
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The Short Answer
Mailchimp is cheaper per contact and much easier to price before you speak to anyone. Klaviyo counts fewer of your contacts as billable and gives an integration far more to work with.
If you send a newsletter to one list and the list is reasonably clean, Mailchimp is almost certainly the right call and the rest of this page is optional reading. Essentials starts at 13 dollars a month and you can find your exact band on a public page in about fifteen seconds.
The case for looking harder is if any of three things are true: you run more than one audience, you have accumulated years of unsubscribes, or you want purchase and event data flowing both ways with HubSpot. Each of those hits Mailchimp's billing model specifically, and the third is where the two platforms stop being comparable products at all.
The Two Platforms Disagree About What a Contact Is
Here are both definitions from the vendors, because almost nobody puts them next to each other.
Mailchimp counts per audience. Audiences do not share data. In Mailchimp's own worded example, if freddie@address.com is in 2 of your audiences, we count that as 2 contacts. Subscribed, unsubscribed and non-subscribed contacts all count toward your contact total and the price of your marketing plan. Cleaned, archived and deleted contacts do not.
Klaviyo counts per account. Any profile, regardless of consent status, that can be emailed through Klaviyo is considered an active profile. A profile is counted once no matter how many lists or segments it belongs to, and profiles that are suppressed or unsubscribed are unreachable through the channel and do not contribute toward billing plans.
Read those three together and the shape is already visible. Mailchimp's bill is driven by how many rows exist across your audiences. Klaviyo's is driven by how many people you can still reach.
That is not a gotcha and Mailchimp is not hiding it. The audience model is an old and deliberate design, it is documented plainly, and Mailchimp's own help centre recommends working around it: as a best practice, run one primary audience and use tags and segments to organise from there. The trouble is that the recommendation is advice to a human, and most multi-audience situations were not created by a human deciding anything. They were created by a form, a campaign, or an integration.
Opt-Out Is Where the Bills Separate
Of everything on this page, this is the row that moves the most money, and it is almost never in a comparison table.
A marketing list of any age is mostly history. Send monthly for three years and a meaningful share of the addresses you started with have unsubscribed, changed jobs or gone silent. On Klaviyo that history costs nothing. The moment somebody unsubscribes they stop being an active profile, they remain in the account for reporting, and your billable count falls on its own.
On Mailchimp the same person keeps their place on the invoice. Unsubscribed is a billable status. So is non-subscribed, which is the status Mailchimp assigns to somebody who interacted with you but never opted in to marketing, and which integrations create in volume.
There is a supported remedy and it works. Archived contacts do not count toward your billing tier, so archiving your unsubscribes is the correct move and it genuinely lowers the bill. It is also entirely manual, nothing in the product prompts you to do it, and the saving is invisible until the next invoice.
The Archive Trap, Which Is Where the Integration Comes In
This is the part that belongs on this site rather than on a review blog, because it is a failure that only exists once two systems are connected.
Archiving is the one lever that removes an unsubscribed contact from a Mailchimp bill. Mailchimp also documents what happens when that person arrives again in an import: when you import contacts that are currently archived, it will automatically unarchive them back to your audience.
A scheduled contact sync is an import. It does not matter that no human pressed a button, or that the contact was already in Mailchimp, or that nobody intended to resurrect anything. If your HubSpot list still contains the people you archived, and something pushes that list into Mailchimp on a schedule, the archive is undone.
The fix is not complicated once you know the shape of it. Whatever archives in Mailchimp also has to suppress on the HubSpot side, so the contact stops being included in what gets sent. Otherwise the two systems hold opposite opinions about the same person, and the one that runs on a schedule wins.
That is the general form of nearly every integration bug worth paying somebody to prevent. Two systems disagree about a record, no arbitration rule was ever written down, and the disagreement resolves in favour of whichever process runs most often. Our data mapping guide covers why this surfaces in week two of every project regardless of which platforms are involved.
The Arithmetic on One Real List
Abstractions are useless here, so take a list of the kind this comes up on.
Eight thousand distinct people in HubSpot. Fifteen hundred of them sit in two Mailchimp audiences, because a product launch created a second audience two years ago and nobody merged it back. Twelve hundred have unsubscribed over the life of the list. Three hundred have hard bounced.
| Population | Mailchimp | Klaviyo |
|---|---|---|
| Distinct people | 8,000 | 8,000 |
| The 1,500 who sit in a second audience | +1,500 | 0 |
| The 1,200 who unsubscribed | counted | -1,200 |
| The 300 that hard bounced | -300 (cleaned) | -300 (suppressed) |
| Billable records | 9,200 | 6,500 |
Two things fall out of that table and they point in opposite directions.
The first is that Mailchimp is billing for about 41 percent more records than Klaviyo for identical data. Nobody entered bad information and no system is broken. One platform is counting memberships and the other is counting reachable people.
The second is that Mailchimp is still probably cheaper, and it would be dishonest to bury that. Mailchimp publishes its whole ladder: contact bands from 0 to 500 up past a million, Essentials from 13 dollars a month, Standard from 20, Premium from 350, with monthly send allowances set as a straight multiple of your contact count at 10x, 12x and 15x by tier. Klaviyo's public pricing page shows the free plan at up to 250 active profiles and 500 email sends a month, and then offers a plan builder. You cannot size a Klaviyo bill from a public page the way you can a Mailchimp one.
So the honest version is this. The record count favours Klaviyo, often substantially. The rate card favours Mailchimp, and the transparency of the rate card favours it again. Which of those wins depends on numbers that only exist in your own account, and you can get them in about ten minutes.
What the HubSpot Connector Costs on Each Side
If you run HubSpot this section is likely to decide it, and the two situations are genuinely not comparable.
For Mailchimp, HubSpot builds and publishes the connectors itself. There are three of them covering different slices, which causes its own confusion, and our HubSpot Mailchimp integration guide works through which one does what and where each stops. What matters here is the commercial part: they are HubSpot's own apps and they do not carry a separate subscription.
For Klaviyo there is no connector from either company. The HubSpot App Marketplace listing is built by KAV Labs, described on the listing as a Klaviyo partner that builds and maintains the app. It requires a Klaviyo plan plus a KAV Labs subscription, starting at 29 dollars a month for up to 1,000 HubSpot contacts in Klaviyo, then 5,000 and 15,000 at the higher tiers. At the time of writing it shows 200 or more installs and no customer reviews.
Two things follow from that, and they cut in opposite directions.
What the Klaviyo connector situation actually means
You are metered on the same person three times. HubSpot prices marketing contacts, Klaviyo prices active profiles, and the connector prices HubSpot contacts synced into Klaviyo. All three meters read the same human being. That is not a scandal and each price is defensible on its own, but it does mean a decision about which contacts to sync is a decision about three bills at once, and it is worth making deliberately rather than by syncing everything because syncing everything is the default.
In exchange it reaches considerably further than the Mailchimp apps do. The listing covers profiles to contacts, engagements, profile and contact properties, deals, deal properties, companies, lists, owners, purchase events to invoices, order events to orders, product data and custom object events. HubSpot's Mailchimp connectors do not go near deals, companies or custom objects. If what you want is CRM context driving email behaviour and email behaviour visible next to a deal, this is a real capability gap and it favours Klaviyo.
A third-party connector is a third-party dependency. Neither of the two companies whose data it moves is responsible for it. That is not a reason to avoid it, and plenty of excellent marketplace apps are built exactly this way, but it is a different risk profile from an app HubSpot ships and maintains, and it deserves a moment's thought rather than none.
What Each One Publishes to Whoever Builds the Integration
This is a build concern rather than a buying concern for most readers, but it is a fair proxy for how much thought each platform has given to being integrated with.
Klaviyo publishes per-endpoint rate limits, per account, on a fixed window with two allowances at every tier. XS is 1 per second burst and 15 per minute steady. S is 3 and 60. M is 10 and 150. L is 75 and 700. XL is 350 and 3,500. Responses carry RateLimit-Limit, RateLimit-Remaining and RateLimit-Reset so you always know where you stand, and on a 429 those are replaced by a Retry-After telling you how many seconds to wait. There is a wrinkle worth knowing before you design anything: requests that use the additional-fields or include parameters are subject to their own stricter limits, tracked separately, so one convenient call can consume three budgets at once.
Mailchimp publishes no rate limit. What it publishes is a cap on simultaneous connections and a statement that there is currently no option to raise that limit on a per-customer basis. The consequences for a build are covered in the Mailchimp integration guide and they are not disqualifying, but the difference in posture is real: one platform hands you a budget to design against, and the other hands you a ceiling to discover.
One platform tells you exactly how much room you have and sells you more of it. The other tells you how many things can happen at once and says the number is not negotiable.
Klaviyo vs Mailchimp, Line by Line
Essentials at 13 dollars a month against a plan builder, a published band for every contact count, and a connector HubSpot builds itself. The audience multiplier cannot hurt you if you only have one audience, and the unsubscribe billing barely registers on a list that has not been running for years. This is most small teams and there is nothing clever to add to it.
These are the two facts the Mailchimp model charges for, and they compound. Every duplicate membership and every historical opt-out is a billable row that would be free on the other platform. Count your own list before deciding, because the gap is entirely a property of your data and can be anywhere from nothing to well over 40 percent.
Deals, companies, products, orders and custom objects move through the Klaviyo connector and nothing comparable exists on the Mailchimp side. If your reason for integrating is that sales should see engagement next to a deal, and that deal stage should drive what marketing sends, this is not a close comparison. It costs 29 dollars a month and up on top of both platforms.
A published ladder of contact bands, and a send allowance expressed as a fixed multiple of contacts, means you can model next year's cost from a public page in a spreadsheet before talking to anybody. Klaviyo's builder may well land cheaper for your list once the record count is accounted for, but you cannot find that out without going through it.
What Neither Price Covers
Both platforms bill for records they are holding. Neither bills for, or detects, the thing that actually goes wrong between a CRM and an email platform, which is the same record being right in one system and wrong in the other.
The archive trap above is one instance. There are others with the same shape. A person unsubscribes in the email platform and stays marketable in HubSpot. A duplicate is merged in HubSpot and the merge does not travel, so two profiles keep receiving. A property is renamed during a cleanup and the sync writes into a field nobody reads any more. In every case both systems report success, because from each one's point of view nothing failed.
This is why the answer to which platform is cheaper is so often less useful than it looks. The number that matters is not the monthly rate. It is how many records you are holding that you should not be, and whether anything in your stack is capable of noticing.
Want to know what your HubSpot is actually syncing into your email platform?
The free audit is genuinely an audit. We look at what is connected to your HubSpot today, which syncs create records you are billed for elsewhere, and which ones are fine exactly where they are. Most of the list usually comes back as leave it alone, and that is a useful answer to have in writing.
Which One to Pick
The decision collapses to three questions, in this order.
How many audiences do you have, and how old is the list? These are the only two facts that make the billing models diverge, and you can answer both today. One audience and a list under two years old means the models agree closely and you should buy on price, which means Mailchimp. Several audiences and years of accumulated opt-outs means you are paying for a population that would be free elsewhere, and the gap is worth measuring properly.
What do you want back in HubSpot? If the answer is a record of sends, opens and clicks on the contact timeline, both sides can do that and Mailchimp's version is included. If the answer involves deal stage driving email, or purchase and order events, or anything touching custom objects, the Mailchimp connectors do not reach and the comparison is over.
Who keeps the two systems honest? Whatever you choose, something has to make suppression travel in both directions, or your contact count will drift upward and no dashboard will tell you. That is a design decision, it takes about an hour to specify, and it is far cheaper than the bill it prevents.
The Bottom Line
Mailchimp is cheaper, more transparently priced, and connected to HubSpot by HubSpot itself. Those are three real advantages and most teams should take them.
What Mailchimp charges for is history. Every duplicate membership, every opt-out, every person who interacted once and never subscribed is a billable row until somebody archives it by hand, and a scheduled sync will quietly put it back. Klaviyo counts reachable people, counts each of them once, and lets the rest fall off on their own. Whether that is worth the higher per-contact price and a paid third-party connector is arithmetic you can do on your own export in ten minutes.
Do that arithmetic before you read another feature table. And whichever way it comes out, write down one rule before anything is connected: which system decides that a person should no longer be emailed, and how that decision reaches the other one. Neither vendor will make that decision for you, and it is the only part of this that costs real money when it is wrong.
