The short version: for most small business owners, MailerLite or Kit (formerly ConvertKit) will do everything you need for under £30 a month, ActiveCampaign is worth the extra cost once you’re selling through automation, and Klaviyo is the right answer only if you run an online shop. There is no single “best” one, but there is a wrong way to choose, which is picking based on features you’ll never touch instead of the list size and business model you have.
Why this question is harder to answer honestly than it should be
I’ve been on Mailchimp, ConvertKit, ActiveCampaign, and Infusionsoft (now Keap) over the years, and I’ve watched dozens of my clients bounce between platforms chasing a feature they saw in a YouTube tutorial. Almost none of them needed to move. The email service was never the problem. The habit of sending was.
Here’s the bit most comparison posts skip: your open rate isn’t a reliable number any more. Since Apple rolled out Mail Privacy Protection in 2021, every email opened in Apple Mail gets marked as “opened” the second it lands, whether a human ever looked at it or not. If a big chunk of your list uses iPhones or iCloud (and in the UK, roughly half do), your open rate is partly fiction. I mention this because half the “which tool is best” articles you’ll read compare open rates between platforms as if that settles anything. It doesn’t. Look at click rate and reply rate instead, they’re much harder to fake.
What decides which platform you need
Before you look at a single feature list, answer these four questions honestly:
- How many people are on your list right now, not in six months’ time?
- Are you selling one thing to everyone, or different things to different segments?
- Do you sell products (needs ecommerce integration) or services (needs simpler automation)?
- Will you build automations yourself, or do you need something you can run with a weekly newsletter and nothing fancier?
Those four answers eliminate about 80 percent of the market for you before you’ve spent a penny.
The main contenders and what they really cost
Mailchimp
Mailchimp is still the name everyone knows, which is exactly why so many small businesses start there and then get an unpleasant surprise. The free plan covers up to 500 contacts. Once you cross that, the Essentials plan runs from around £11 to £13 a month at 500 contacts, but the pricing climbs fast as your list grows, because Mailchimp counts unengaged subscribers too. I had a client on a list of 38,000 paying close to £270 a month, and when we checked engagement, fewer than 6,000 of those people had opened anything in the previous eight months. She was paying to email ghosts. We cleaned the list, moved her down a tier, and cut her bill by more than half in one afternoon.
Mailchimp is fine for beginners with small lists and simple newsletters. It gets expensive and clunky the moment you want proper segmentation or multi-step automation.
MailerLite
This is what I recommend most often to service-based small businesses starting from scratch. The free plan covers up to 1,000 subscribers and includes automation, landing pages, and a drag-and-drop builder, which is unusually generous. Paid plans start around £8 to £10 a month once you’re past that. The interface is clean, the automation builder is simple to learn in an afternoon, and deliverability has been solid every time I’ve tested it. The downside is that its CRM-style features are basic compared to ActiveCampaign, so if you’re running complex sales funnels with lead scoring, you’ll outgrow it.
Kit (formerly ConvertKit)
Kit rebranded from ConvertKit in 2024 and it’s built specifically for creators and coaches who sell courses, memberships, or their own expertise rather than physical products. The free plan now covers up to 10,000 subscribers with basic features, which is a serious offer if you’re growing an audience before you monetise. Paid plans start around £22 to £25 a month for 1,000 subscribers with full automation and tagging. Tagging, not list-based segmentation, is the whole design philosophy here, and once you understand tags versus lists, it’s one of the most flexible tools out there for anyone building an audience through content, which ties directly into how you’re doing your keyword research to bring people onto that list in the first place.
ActiveCampaign
This is the one I moved to myself once my list crossed roughly 20,000 people and I needed real behavioural automation, not just “if opened, then send this.” Plans start around £15 a month for 500 contacts on the Lite tier, but the useful stuff, the automation builder with conditional branching, lead scoring, and CRM features, sits on the Plus plan, closer to £70 a month at that list size. It has a genuine learning curve. I spent a full weekend building my first proper automation sequence and got it wrong twice before it worked the way I wanted. But once it’s built, it runs itself, and that’s the trade-off with ActiveCampaign: more setup time for more return once you’re selling through email rather than just newsletter-ing.
Klaviyo
If you run an online shop, especially on Shopify or WooCommerce, stop reading the general comparisons and just look at Klaviyo. It’s built around ecommerce data from the ground up, so it can trigger emails based on what someone browsed, abandoned, or bought, and tie revenue directly back to each email in your reports. The free plan covers up to 250 profiles, and pricing then scales with both list size and email volume, so a shop with 5,000 contacts might pay somewhere between £35 and £60 a month. For anyone weighing this against building an affiliate marketing programme instead of relying purely on your own list, Klaviyo’s segmentation makes it far easier to reward repeat buyers and referrers automatically.
Brevo (formerly Sendinblue)
Brevo charges by number of emails sent per day rather than list size, which suits a specific type of small business: one with a big list but a low sending frequency. The free plan allows 300 emails a day. Paid plans start around £7 to £8 a month and don’t cap your contact list at all, only your daily send volume. If you’ve got 15,000 people on your list but only email them twice a month, Brevo can work out far cheaper than list-based pricing tools.
The uncomfortable truth about email tools
Here’s the part that won’t sell you a course: the platform makes maybe 15 percent of the difference to your results. The other 85 percent is whether you send consistently and write like an actual person rather than a brand voice guideline. I’ve seen a sole trader on the free version of MailerLite outperform a company on a £300-a-month ActiveCampaign plan, simply because she emailed her 900 subscribers every single week with something useful, and they barely touched their automations at all. AI can now help draft that weekly email in minutes, and it’s worth understanding how AI changes your marketing strategy before you assume the tool itself needs replacing. Most small businesses don’t have an email software problem. They have a “we stopped sending in March and never restarted” problem, and no platform on this list fixes that.
A simple way to choose in 20 minutes
- Count your current list size and write it down.
- Decide: are you selling products, services, or building an audience around your own expertise?
- If products, shortlist Klaviyo. If services or coaching, shortlist MailerLite or Kit. If you’re already running complex funnels, shortlist ActiveCampaign.
- Sign up for the free plan of your top pick and send one real email to your list within 48 hours, not a test email to yourself.
- Check click rate, not open rate, after 72 hours before you decide whether to upgrade.
That last step matters more than any feature comparison chart. You learn more from one real send than from an hour of reading reviews.
What I’d use in 2026 if I were starting again
If I had zero subscribers and a service-based business tomorrow, I’d start on MailerLite’s free plan and stay there until I hit 1,000 people. If I were building a personal brand or selling a course, I’d start on Kit. If I sold physical products online, Klaviyo, full stop, no debate. And I’d revisit the choice at the point where I was writing more than three automated sequences a month, because that’s when ActiveCampaign’s extra cost starts paying for itself. Whichever you pick, most of these tools now bolt on AI subject line testing and send-time optimisation as standard, which is worth comparing alongside the wider list of AI tools for different business tasks before you assume you need a separate app for it.
Frequently asked questions
What is the cheapest email marketing service for a small business?
MailerLite’s free plan (up to 1,000 subscribers, including automation) and Brevo’s free plan (300 emails a day, unlimited contacts) are the two cheapest usable options in 2026. Mailchimp’s free tier looks cheap but becomes one of the more expensive options as soon as your list grows past 500.
Is Mailchimp still worth it in 2026?
Mailchimp works fine for a beginner with under 1,000 contacts and simple newsletter needs, but it gets expensive fast because it charges based on total contacts including unengaged ones, and its automation features lag behind MailerLite and ActiveCampaign at similar price points.
Which email service is best for an online shop?
Klaviyo is built specifically for ecommerce and integrates directly with Shopify and WooCommerce, letting you trigger emails based on browsing and purchase behaviour and see exact revenue attributed to each campaign, which general-purpose tools can’t match.
Do I need paid automation features if I’m just starting out?
No. A weekly consistent email to a small, honest list of real subscribers will outperform a fancy automated sequence sent by a business that emails once a quarter. Start on a free plan, send consistently for three months, then upgrade based on what you need, not what you think you might use.
