Best free email marketing software for UK small businesses

If you run a small business in the UK, an email list is one of the few marketing channels you fully own. The good news is that you don't need to pay anything to start one. The catch is that every "free" plan is designed to push you towards an upgrade at some point, and the limits are in very different places. One tool caps contacts, another caps monthly sends, another holds back automations.

This guide focuses only on what you get for free and where each free plan runs out, so you can pick the one that will last longest for your type of business. Every limit and price below was checked on the vendor's official pricing page in October 2026 (prices checked October 2026). All three list prices in US dollars, so the sterling amount on your card statement will move with the exchange rate. If you want a broader feature-by-feature comparison, including paid plans, read our Systeme.io vs MailerLite vs Kit comparison.

Free plans compared

Sources: Systeme.io pricing, Kit pricing, MailerLite pricing, all checked October 2026.

1. Systeme.io: the most generous all-round free plan

Systeme.io is an all-in-one platform for selling online: email marketing, sales funnels, a checkout, online courses, a blog and an affiliate programme sit in one account. According to its pricing page, the free plan supports up to 2,000 contacts, 3 sales funnels, 1 blog, 1 course (up to 500 students), 1 affiliate programme and 1 custom domain, with unlimited email sends. It never expires and doesn't ask for a credit card.

Two limits matter most for email. You get one automation rule and one email campaign on the free plan. That is enough to send regular newsletters to a list of up to 2,000 people and run a simple "tag new subscribers" rule, but not enough for a set of welcome, nurture and follow-up sequences. For that, the next step is the Startup plan at $17 a month for 5,000 contacts, then Webinar at $47 for 10,000 contacts and Unlimited at $97. Systeme.io says every plan includes unlimited email sends and 0% transaction fees, and that if you cancel a paid plan your account reverts to the free plan.

Best for: coaches, consultants, trainers and anyone selling a course, digital download or service who wants list-building and selling in one place without paying.

Not ideal for: product shops already on Shopify, which don't need Systeme.io's funnels and checkout. Read our full Systeme.io review.

2. Kit: the biggest free list, if you can live without automations

Kit (formerly ConvertKit) is built for creators and newsletter-led businesses. Its pricing page lists a free plan for up to 10,000 subscribers with unlimited landing pages and forms, unlimited email broadcasts, tagging and segmentation, and the ability to sell digital products and subscriptions.

What you don't get for free is automation. Kit lists visual automations, email sequences, A/B testing of subject lines, RSS campaigns and removal of Kit branding as features of its paid Creator plan, which was listed at $33 a month billed yearly ($390 a year) for 1,000 subscribers when we checked. Paid plans come with a 14-day free trial with no card required, and Kit offers free migration from another platform.

Best for: writers, podcasters, makers and service businesses whose main email is a regular newsletter, and who want to grow a large list before paying anything.

Not ideal for: businesses that need an automated welcome series from day one. We don't currently rank Kit in our main list, so there is no editor rating for it.

3. MailerLite: polished email for very small lists

MailerLite is a focused email marketing tool with three editors (drag-and-drop, simple and custom HTML), a visual automation builder, sign-up forms, landing pages and simple websites. Its free plan, per the pricing page, covers up to 250 subscribers, 2,500 emails a month and 2 user seats, with 3 active automations (5 steps each), 1 website, 1 landing page, 3 active forms and 1 digital product or booking. Support on the free plan is community-based.

The 250-subscriber cap is the tightest of the three, and MailerLite says that if a free account goes over it, sending (campaigns and automations) is locked until you upgrade or remove subscribers. Paid plans start with Comfort from $12 a month, which gives you ten times your subscriber tier in monthly sends and 50 automations, and Power from $25 a month with unlimited emails and 24/7 live chat. New accounts get a 14-day trial of premium features with no card required, and nonprofits get 30% off paid plans.

One point UK businesses often ask about: MailerLite states that its data storage centre is in the European Union with ISO 27001 certification, and that it has GDPR controls in place. Its prices are shown in USD or EUR and "may be subject to applicable taxes".

Best for: new businesses with a small list who want well-designed emails and expect to pay a modest monthly fee once they grow. Read our full MailerLite review.

Which free plan lasts longest?

It depends on where your growth will hit first:

• You'll grow your list quickly but only send newsletters: Kit's 10,000-subscriber free plan will last longest.
• You want to sell something and email the buyers: Systeme.io's free plan gives you a checkout, funnels and unlimited sends up to 2,000 contacts.
• You need several automations immediately: MailerLite's 3 free automations are the most on offer, but only for 250 subscribers. Beyond that you're likely paying on any platform.
• You send to a list several times a week: avoid plans with a monthly send cap. MailerLite's free 2,500 sends would cover a 250-person list ten times a month.

UK rules to follow on any free plan

A free tool doesn't change your legal obligations. In the UK, marketing emails to individuals are covered by the Privacy and Electronic Communications Regulations (PECR) as well as UK GDPR. The ICO's guidance on electronic mail marketing says, in short:

• You need specific consent to send marketing emails to individuals, with a limited "soft opt-in" exception for your own previous customers who bought, or negotiated to buy, similar products or services, provided you offered a simple opt-out when you collected their details and in every message.
• Sole traders and some partnerships are treated as individuals.
• Every email must identify you and include a valid way to unsubscribe, and you should keep a "do not contact" list.
• Don't use bought-in lists of individuals: the soft opt-in doesn't cover them.

The ICO notes this guidance is under review following the Data (Use and Access) Act, so check the latest version. All three tools provide sign-up forms and unsubscribe links, but it's still your job to word your consent clearly and keep records.

Tips to get more from a free plan

• Clean your list. Contacts usually count towards your limit, so remove people who have never opened an email.
• Authenticate your domain. Set up SPF, DKIM and DMARC records using your provider's help docs. It's free and helps your emails reach inboxes.
• Connect your other tools. If your free plan doesn't integrate with a particular app, an automation tool can bridge the gap. See our guides to Make's free plan and Make vs Zapier.
• Plan your upgrade. Check the first paid tier before you commit: moving platforms later means rebuilding forms and automations.

Bottom line

For most UK small businesses that sell their own services, courses or digital products, Systeme.io's free plan is the most useful place to start: 2,000 contacts, unlimited sends and the selling tools you'd otherwise pay for separately. Choose Kit if a large newsletter is your main goal and automations can wait, and MailerLite if your list is small and you want the most polished email editor.

Frequently asked questions

Prices and plan limits change frequently. We note the date we checked each fact; always confirm on the vendor's official pricing page before buying. Spotted something out of date? Tell us.