Klaviyo wins for online stores: it bills only active profiles and puts advanced flows and revenue attribution on every paid plan. Mailchimp wins for everyone else, with a cheaper entry plan, more templates and broader integrations. Their free plans are effectively identical, so a free tier is not a reason to choose between them.
Plans and pricing checked July 2026, and every figure below comes from our live pricing database rather than a review site.
The free plans are a dead heat
This is the first myth to clear, because most comparisons still present a free plan as Mailchimp's advantage. It is not, at least not against Klaviyo.
- Klaviyo free plan: Yes (250 profiles, 500 emails /mo)
- Mailchimp free plan: Yes (250 contacts, 500 sends /mo)
They are the same shape and effectively the same size. Both are capped on two axes at once, contacts and monthly sends, and the send cap is the one that bites: a couple of hundred subscribers emailed twice a month exhausts it. Treat both as trial tiers, not as a place to run a business from. If a genuinely usable free plan is what you are looking for, this is the wrong matchup, and our Mailchimp alternatives guide points at the tools that offer one.
Pricing and plans compared
Mailchimp is the cheaper way in. Its entry plan is £9.76/mo (Essentials) against Klaviyo's £15/mo (Email), both billed natively in pounds, so there is no exchange rate to factor in and the comparison is clean.
Two things narrow that gap, and both matter more than the headline.
The first is what you are billed for. Mailchimp counts All contacts including unsubscribed, so people who unsubscribed two years ago still sit on your bill until you delete them. Klaviyo counts Active profiles only (excludes suppressed). On a young, clean list the difference is nothing. On a list that has been running for three or four years with normal churn, it is the difference between one pricing tier and the next.
The second is what the entry plan can do. Mailchimp's automation is Basic (Essentials), Advanced (Standard+), so the plan you compare on price is not the plan that runs multi-step workflows. Klaviyo's is Advanced (flows, triggers, predictive on every paid plan). If automation is why you are buying an email tool, you should be comparing Klaviyo's entry plan against Mailchimp's Standard plan, not its Essentials plan, and on that footing Mailchimp's price advantage largely disappears. The calculator above does this properly for your own subscriber count.
Who each one is built for
Klaviyo is for UK businesses that sell online. Its whole design assumes a store sits behind the list: Shopify (deep native), WooCommerce, BigCommerce, Magento, with segmentation that is Very advanced (predictive, purchase behaviour, CLV) and reporting that is Yes (revenue). If you can answer the question "what did this email actually sell", Klaviyo pays for itself. If you cannot, you are paying for machinery you will never switch on.
Mailchimp is for everyone else. A consultancy, a charity, a gym, a professional services firm, a business that emails a newsletter and a promotion and wants it to look right without a designer. Mailchimp gives you 100+ templates and 300+ integrations, and it is the tool your marketing hire will already know.
Automation and segmentation
This is where the two genuinely diverge, and it is not close.
Klaviyo builds around behaviour: what someone browsed, what they bought, what they are predicted to spend. Flows trigger off store events, segments recompute themselves, and every paid plan gets the full set. A/B testing is Yes (all paid plans).
Mailchimp's segmentation is Moderate (tags, predicted demographics), which is fine for interest tags and basic lifecycle sends, and its A/B testing is Yes (Standard+). It will run a welcome series and a re-engagement sequence competently. It will not do purchase-triggered revenue automation at Klaviyo's level, and pretending otherwise is how people end up disappointed with it.
Ease of use and templates
Mailchimp is the easier first week by a distance. The editor is familiar, the template library is the largest in the category, and there is a decade of tutorials for every question you will have.
Klaviyo asks more of you. Its value is unlocked by connecting your store, mapping your events and building flows around them, and none of that happens on day one. A store owner willing to spend a weekend on setup gets far more back. A sole trader who wants to send a monthly update will find it heavy and never use most of it.
UK considerations
Both are billed in pounds, so your invoice is a fixed amount each month with no currency movement to track.
On compliance, Klaviyo is Yes (consent tools, unsubscribe, sender ID) and Mailchimp is Yes (consent tools, unsubscribe, sender ID). Both give you the consent capture and unsubscribe handling that UK GDPR and PECR require, so neither creates a compliance problem, though the legal duty to hold real consent stays with you either way.
SMS is the clearer UK split. Klaviyo's UK SMS is Yes (UK supported, 5 credits/SMS), and text sits inside the same flows and segments as email, so a message can be step three of a sequence rather than a separate campaign. Mailchimp's UK SMS is Yes (UK SMS, paid add-on), and it is bolted alongside your campaigns rather than built into them. If text is part of the plan, Klaviyo is the one built for it here.
Pros and cons for this matchup
Klaviyo wins on advanced automation included on every paid plan, predictive and purchase-based segmentation, revenue attribution, a deep Shopify integration, native UK SMS inside flows, and billing only for profiles that are actually active. It loses on price, on learning curve, and on being comprehensively over-specified for a business that does not sell online.
Mailchimp wins on the cheaper entry plan, the largest template library, the broadest integration ecosystem and by being the tool everyone already knows. It loses on billing you for contacts who have unsubscribed, on holding proper automation back for a higher tier, and on segmentation that cannot follow a customer through a purchase the way Klaviyo's can.
The verdict
If you sell online, choose Klaviyo. The higher entry price buys automation on every plan, segmentation that understands buying behaviour, and a bill that ignores the dead weight in your list. For a UK store, it is not a close decision.
If you do not sell online, choose Mailchimp. Klaviyo's advantages are all e-commerce advantages, and paying for them to send a monthly newsletter is money set on fire. Mailchimp is cheaper to start, easier to learn and better stocked with templates.
Do not let the free plans decide it. They are the same size, they are both trial tiers, and neither will carry a real list. Put your own subscriber count into the calculator above, and if you want the wider field, our UK email marketing comparison has every platform we track.