Best Email Marketing Software for Small Businesses: What You Really Pay at 2,500 and 10,000 Contacts

The best email marketing software for a small business is the one whose billing unit matches how you actually send. That sounds like a technicality. It is the single biggest reason a plan advertised at a low monthly figure turns into a much larger invoice a year later, and it is the part most comparison articles skip.

Email platforms do not all measure you the same way. Some charge by contacts, some by emails sent, some count unsubscribed people in your total and some do not, and when you go over a limit some charge an overage, some move you up a tier automatically and some stop your sends. We read each vendor's own pricing page and billing documentation on 16 September 2026 and built the comparison below from those pages only. We did not run campaigns through these platforms and we did not measure deliverability, so there are no inbox placement rankings here.

The short answer: which email marketing tool fits which small business

Pick by list size, sending frequency and whether you sell online, then check the billing unit before you commit.

How each vendor measures you: the billing unit comparison

This is the table that decides your real cost. Every row was read from the vendor's pricing page or billing help documentation on 16 September 2026.

Where a cell says not stated, we could not find the answer on the vendor's public pricing page and did not fill the gap from third-party summaries. Ask sales before you rely on it.

Is it cheaper to pay per contact or per email sent?

Per email sent is cheaper if you have a big list and send rarely. Per contact is cheaper if you have a small list and send often. Brevo is the clearest example of the first model. Its pricing page sets the Starter price by monthly email volume, labelled campaigns and transactional, and it sells pay-as-you-go credits where one email sent equals one credit and credits do not expire.

There is a catch that the common description of Brevo as having unlimited contacts misses. On 16 September 2026 the Starter configurator attached a contact allowance to each volume step: 5,000 emails a month came with 500 contacts at $9, 10,000 emails with 1,500 contacts at $17, and 15,000 emails with 2,500 contacts at $25. From 20,000 emails a month at $32, the allowance jumped to 500,000 contacts. So at small volumes the contact count still matters, even on the plan that is priced by sends.

Contact-based vendors flip the logic: the list size sets the price and a send cap is derived from it. Mailchimp's plan documentation sets the monthly send limit at 10 times your contact limit on Essentials, 12 times on Standard and 15 times on Premium. MailerLite Comfort uses 10 times the ceiling of your subscriber tier, and Omnisend Standard uses 12 times your list. At weekly sending, none of those caps bite. At daily sending, a 10x cap runs out in the second week.

Do unsubscribed contacts count toward my email marketing bill?

At Mailchimp, yes. This is the most expensive detail in the whole category and the one comparison articles almost never state. Mailchimp's help documentation says subscribed, unsubscribed and non-subscribed contacts are all included in your contact count, while archived, cleaned and deleted contacts are not.

In practice that means a list of 2,500 subscribers that has accumulated 600 unsubscribes over the years is billed as 3,100 contacts. Mailchimp's pricing page sells in contact bands, and on 16 September 2026 the bands ran 1,501 to 2,500 and then 2,501 to 5,000. Those 600 people who asked never to hear from you push the account into the next band. The fix is to archive unsubscribed contacts, which removes them from the count.

The other vendors we checked take the opposite position. MailerLite says subscribers who have unsubscribed or bounced do not count. Kit counts only unique and active subscribers. Klaviyo's billing documentation, last updated 25 March 2026, says suppressed or unsubscribed profiles stay in the account for reporting but are not included in the billable count once processed. Omnisend says unsubscribed contacts are not billed, but it does bill non-subscribers who received automated messages, such as a customer who bought once and was sent a follow-up.

MailerLite adds one subtlety worth knowing before you clean a list: it uses a cumulative count within each billing cycle. An address that was active at any point in the cycle counts, even if you delete it later, until the count resets on your billing anniversary. Delete just after that date, not just before it.

What happens if my list grows past my plan's contact limit?

You will almost never be cut off on a paid plan. You will be charged more, and the only question is how. The three behaviours we found:

1. Overage charge, service continues. Mailchimp says it will not interrupt service when your contact total goes over the limit during a billing cycle; you see an additional charge on your bill instead. Its pricing page adds that overages apply if either the contact or email send limit is exceeded.
2. Automatic upgrade to the next tier. MailerLite raises your subscriber limit and charges your card for the next tier. Kit automatically upgrades you to the next subscriber tier, and its FAQ adds that if you clean your list and fall back under, its team has to downgrade the plan manually, so you must email support to stop paying for the higher tier. Klaviyo moves you to a tier with enough profiles from the next billing cycle.
3. Sending stops. This is the free plan behaviour almost everywhere. Mailchimp places a hold on sending over 250 contacts, MailerLite locks campaigns and automations over 250 subscribers, and Klaviyo says free accounts cannot send additional emails once over 250 active profiles or 500 monthly sends.

Klaviyo is the one vendor that lets you choose what happens when you hit the send limit: pay flexible overages at your plan's unit rate, auto-upgrade, or stop sending. If a surprise invoice would hurt more than a paused campaign, set that option deliberately.

How much will email marketing cost with 2,500 or 10,000 contacts?

Here is the worked example most comparisons leave out. The assumption is a small business sending one campaign a week, so four sends a month: 10,000 emails a month at 2,500 contacts and 40,000 emails a month at 10,000 contacts. Every price is the monthly-billing figure the vendor's own configurator showed on 16 September 2026, in US dollars, before tax.

Annual billing lowers most of these. MailerLite Comfort dropped to $29.70 and $80.10 a month on yearly billing, Kit Creator to $50 and $116 a month, and Brevo Starter to $22.50 and $41.42. Omnisend offered 30 percent off for paying three months upfront, which is why its headline prices look lower than the monthly figures above.

Mailchimp, Klaviyo, ActiveCampaign and Constant Contact are missing from the table on purpose. Mailchimp and Constant Contact served us region-specific pricing rather than US prices, ActiveCampaign's page did not display prices without a quote, and Klaviyo's page published only its entry price, $20 a month for 251 to 500 active profiles on the Email plan. We would rather leave a cell out than print a number we did not read at source. Use each vendor's calculator with your own contact count before you compare.

Which email marketing tools have a permanent free plan?

Several do, and the caps vary enormously. These are permanent free tiers, not trials:

• Kit: up to 10,000 subscribers, the largest free subscriber cap we found.
• beehiiv Launch: up to 2,500 subscribers with unlimited email sends.
• Resend: 1,000 marketing contacts, plus 3,000 transactional emails a month capped at 100 a day.
• Brevo: up to 300 emails a day once your account is approved for sending.
• MailerLite: up to 250 subscribers and 2,500 emails a month.
• Mailchimp: 250 contacts and 500 sends a month, 250 a day.
• Klaviyo: 250 active profiles and 500 email sends a month, with full email support only for the first 60 days.
• Omnisend: 250 contacts and 500 emails a month.

ActiveCampaign offers a 14-day free trial rather than a free plan, and Constant Contact offers a 30-day refund guarantee rather than a free tier.

Free tier caps also change. Zapier's Mailchimp alternatives roundup, last updated in March 2026, describes MailerLite as free for up to 500 subscribers and 12,000 emails a month with a paid plan called Growing Business. MailerLite's own page on 16 September 2026 showed a free cap of 250 subscribers and 2,500 emails, and paid plans named Comfort and Power. If you plan around a free tier, read the vendor's page on the day you sign up.

What are the cheapest Mailchimp alternatives?

At the two list sizes we priced, the cheapest paid options were Brevo Starter at $25 and $46 a month and MailerLite Comfort at $33 and $89, with Kit's free plan beating both if you can live without its paid automation features. The honest caveat is that we could not price Mailchimp itself in US dollars at these sizes, so we cannot give you a verified percentage saving.

What we can say is structural. If your Mailchimp account carries a lot of unsubscribed contacts, you are paying for them and you would not be at MailerLite, Kit, Klaviyo or Omnisend. Archiving them in Mailchimp is the free first step. If you send rarely to a large list, a send-based model like Brevo's is likely to beat any contact-based plan. If you need receipts and order confirmations too, note that Mailchimp sells its transactional product as a paid add-on on Standard and Premium, while Brevo includes transactional email on every plan.

Is transactional email included in email marketing plans?

Usually not, and it matters if you run a store or an app. Transactional email is the one-to-one mail triggered by an action, such as order confirmations and password resets. Brevo includes it on all plans, with APIs, SMTP and webhooks, but it counts toward the same monthly email volume. Mailchimp sells Mailchimp Transactional as a paid add-on for Standard and Premium. MailerLite points you to its sister product, MailerSend. Resend is built the other way round: transactional is the core product, with marketing plans priced separately by contacts.

If you need both, check whether transactional sends eat into your marketing allowance, as they do on Brevo, before sizing your plan.

Which email marketing platform is best for an ecommerce store?

Omnisend and Klaviyo are the two built around store data, and the choice between them comes down partly to billing. Omnisend publishes tier prices openly: $44 a month on Standard at 2,500 contacts and $132 at 10,000, with Pro adding unlimited sends and SMS from $0.007 a message. It bills non-subscribers who received automated messages, which in a store includes one-time buyers who got a post-purchase flow.

Klaviyo defines an active profile as any profile that can be emailed regardless of consent status, so checkout contacts count, and it publishes only its entry price openly. Its advantage is control: you choose whether exceeding your send limit triggers overages, an upgrade or a stop. Klaviyo's page also notes that SMS and mobile messages are metered separately.

A note on deliverability, since every vendor markets it. Constant Contact's pricing page claims a 98 percent inbox rate based on 2025 Validity Everest test results. That is a vendor claim about its own qualified test, not an independent measurement, and we did not test any platform's inbox placement. Your own list hygiene and authentication will move your results more than a headline percentage.

How to choose without overpaying

Start with three numbers: your total contacts including unsubscribes, how many emails you send a month, and how fast the list is growing. Then work through this order.

1. If you are under 10,000 subscribers and do not need paid automation features, try Kit Free first.
2. If your list is large and you send less than weekly, price Brevo by volume, and check the contact allowance at your volume step.
3. If you send weekly or more to a list you keep clean, compare MailerLite and Omnisend at your exact tier, monthly and annual.
4. If you are staying on Mailchimp, archive unsubscribed contacts before your next billing date.
5. Whatever you choose, find out what happens when you exceed the limit, and on Kit remember that a smaller list does not downgrade the plan by itself.

Then read the price on the vendor's page on the day you buy, on the billing basis you intend to use. Plan names and free caps in this category have changed within months, and the article you read last quarter may already be wrong.