The short answer: the best AI email marketing tool depends on what you sell. Klaviyo is the strongest pick for online stores, Brevo is the cheapest credible platform for small lists, and Kit is the easiest ride for creators and newsletter writers. Mailchimp remains the safe default for general small business — but its free plan shrank hard in 2026, and every platform on this list bills you in a different way, which is where the real cost differences hide.
Best AI email marketing tools at a glance
| Tool | Starting price | Free plan | Bills by | Best for |
|---|---|---|---|---|
| Klaviyo | $20/mo at 500 profiles | 250 profiles, 500 sends/mo | Active profiles | E-commerce stores |
| Brevo | Starter from $9/mo | 300 emails/day | Emails sent | Small budgets, big quiet lists |
| Kit | Paid tiers by subscriber count | Up to 10,000 subscribers | Subscribers | Creators and newsletters |
| Mailchimp | Essentials from $13/mo | 250 contacts, 500 sends/mo | Contacts stored | General small business |
| Omnisend | Standard from $16/mo | 250 contacts, 500 emails/mo | Billable contacts | E-commerce on a budget |
| HubSpot Marketing Hub | Starter priced per seat | Free tools tier | Seats + contacts | Teams that also need a CRM |
What the pricing pages don’t make obvious
Three billing gotchas, all verified against the vendors’ own pricing terms this month. Klaviyo bills on active profiles — every contactable person in your account, whether or not you emailed them that month — and it auto-upgrades your plan when your profile count crosses a tier. List hygiene is now a direct cost, not just good practice. Brevo’s free plan stores up to 100,000 contacts, but its cheapest $9 Starter tier (5,000 emails a month) caps stored contacts at 500 — a free account holding 3,000 contacts cannot simply buy the $9 tier to escape the daily send cap; it has to buy a higher-volume tier. And Mailchimp counts unsubscribed contacts toward your billable total until you archive them, on top of a January 2026 free-plan cut from 500 contacts and 1,000 sends down to 250 contacts and 500 sends.
1. Klaviyo — best for e-commerce
Klaviyo’s AI builds segments, drafts subject lines and flows, and predicts customer lifetime value from real purchase data, which is why it owns the Shopify end of this market. Pricing is free up to 250 active profiles with 500 sends a month, then $20 a month at 500 profiles, $30 at 1,000, $100 at 5,000, and $150 at 10,000 on the Email plan. It is powerful and, at scale, genuinely expensive — the active-profile model above is why. Stores should also read our roundup of the best AI tools for e-commerce store owners.
- Pros: Deepest e-commerce data and automation here; strong AI segmentation and predictive analytics; huge integration library.
- Cons: Bills for profiles you never email; auto-upgrades with no opt-out; costs climb steeply past 10,000 profiles.
Best for: Shopify and WooCommerce stores doing real revenue per email.
2. Brevo — best value for small senders
Brevo (formerly Sendinblue) flips the usual model: you pay for emails sent, not contacts stored. The free plan sends 300 emails a day, forever, with no card required. Starter begins at $9 a month for 5,000 emails and Standard at $18 adds proper marketing automation and A/B testing. Its AI assists with subject lines, send-time optimisation, and copy inside the campaign builder. Watch the Starter contact caps described above, and note that removing Brevo branding on Starter is a paid add-on.
- Pros: Cheapest credible paid entry here; free plan suits infrequent senders with large lists; transactional email included in the same account.
- Cons: 300-a-day free cap blocks one-off blasts to a big list; entry Starter tiers cap contacts far below the free plan; branding removal costs extra on Starter.
Best for: small businesses and newsletters that send occasionally and hate per-contact billing.
3. Kit — best for creators and newsletters
Kit (formerly ConvertKit) is built around one list, tags instead of multiple audiences, and a creator-friendly editor, with AI help for subject lines and its Recommendations network for growing via other newsletters. Its free Newsletter plan covers up to 10,000 subscribers — by far the most generous free ceiling on this list — while paid tiers are priced by subscriber count and climb fast once automations and advanced reporting kick in. We covered the full ladder in our Kit review.
- Pros: 10,000-subscriber free plan; simple tagging model; built-in paid recommendations and digital product sales.
- Cons: Paid tiers climb quickly with list size; reporting and design flexibility trail Mailchimp and Klaviyo.
Best for: newsletter writers, course creators, and coaches.
4. Mailchimp — best general-purpose default
Mailchimp’s AI (Intuit Assist) drafts campaigns, subject lines, and product copy, and its Creative Assistant assembles on-brand designs. The free plan now holds just 250 contacts and 500 sends a month, with no automation. Essentials starts at $13 a month for 500 contacts; Standard, from $20, is where the generative AI features and up to 200 automation flows live, and it reaches $100 a month at 5,000 contacts. Remember to archive unsubscribed contacts — they bill you until you do. For the copy side of campaigns, our Copy.ai review covers a cheap drafting companion.
- Pros: Easiest editor for beginners; 300+ integrations; mature templates and reporting.
- Cons: Free plan cut in January 2026; unsubscribed contacts count toward billing; price jumps fast between contact bands.
Best for: general small businesses that want the familiar, safe option.
5. Omnisend — best budget e-commerce alternative
Omnisend packs email, SMS, and push into pre-built e-commerce workflows, with an AI writer for subject lines and campaign copy included on every plan, free included. The free plan covers 250 contacts and 500 emails a month with most features unlocked; Standard starts at $16 a month for 500 contacts with sends at 12 times your contact count, and Pro from $59 adds unlimited email. One watch-out: its billable contacts can include non-subscribers, such as checkout customers who never opted in.
- Pros: Free plan includes nearly all features; email + SMS + push in one place; cheaper than Klaviyo at most list sizes.
- Cons: Billable-contact definition surprises people; SMS is now a separate add-on for newer accounts; free volume is small.
Best for: smaller stores that want Klaviyo-style flows without Klaviyo pricing.
6. HubSpot Marketing Hub — best when you also need a CRM
HubSpot’s AI drafts emails and campaigns inside a full CRM, so email performance ties directly to deals and pipelines. The free tools tier is a real starting point, and paid Marketing Hub plans are priced per seat, which suits small teams but gets expensive as headcount and contact tiers grow. Choose it when the CRM is the point; choose anything above when email is the point.
- Pros: Best-in-class CRM integration; strong free tier; AI assistance across email, landing pages, and reporting.
- Cons: Per-seat pricing multiplies fast; contact-tier jumps on renewal are a common complaint; overkill for a simple newsletter.
Best for: B2B teams managing leads, not just lists.
Frequently asked questions
What is the best free AI email marketing tool?
Kit, for creators: its free plan covers up to 10,000 subscribers. Brevo’s free plan is better if you send rarely to a large stored list — 300 emails a day, up to 100,000 contacts stored.
Why did my Klaviyo bill go up when I didn’t send more email?
Klaviyo bills on total active profiles, not on who you emailed, and auto-upgrades your tier as profiles grow. Prune or suppress inactive profiles to control it.
Is Mailchimp still free?
Yes, but barely: since January 2026 the free plan caps at 250 contacts and 500 sends a month, with no automations. Most real lists outgrow it immediately.
Which tool is cheapest for a 5,000-contact list?
Usually Brevo if you send infrequently, because it bills per email sent. On per-contact models, 5,000 contacts run about $100 a month on both Klaviyo’s Email plan and Mailchimp Standard.
The verdict
Stores: Klaviyo if email drives serious revenue, Omnisend if it doesn’t yet. Creators: Kit, and it isn’t close. Everyone else: start on Brevo’s free plan, learn your real sending volume for a month, and only then let anyone bill you per contact.