How Much Does Email Security Cost for a Small Business?

Last updated: 26 June 2026.

Email is still where most attacks land. Phishing was identified by 85% of UK businesses that suffered a breach in the past year (Cyber Security Breaches Survey 2025, DSIT). The good news: meaningful protection is cheap relative to the cost of getting it wrong. This guide breaks down what each layer actually costs, what you get for the money, and how to size a realistic budget. For the wider picture of where email fits, see our managed cybersecurity for UK SMEs pillar.

What does email security actually cost in 2026?

Email security is priced in layers, not as a single line item. Most UK SMEs pay between £1.80 and £8 per user per month all-in, depending on whether they buy a Microsoft add-on, bundle it inside Microsoft 365 Business Premium, or hand the whole thing to a managed provider. The table below shows the realistic ranges.

The cheapest number on the page is rarely the right answer. A licence you never configure protects nobody. The real cost question is "protection plus the time to run it" — which is where a managed layer earns its keep.

What do you already get with Microsoft 365's built-in email security?

Every Microsoft 365 plan includes Exchange Online Protection (EOP) at no extra cost. EOP gives you baseline anti-spam and anti-malware filtering on inbound and outbound mail. It is genuinely useful and blocks the bulk of commodity spam — but it is a floor, not a finished email security posture.

EOP does not include the advanced anti-phishing, Safe Attachments (detonating files in a sandbox), or Safe Links (rewriting and scanning URLs at click time) that you get with Microsoft Defender for Office 365. Microsoft documents the difference between the two tiers in its Office 365 security comparison. For a business that handles invoices, payroll or client data over email, the gap between "basic filtering" and "active phishing defence" is the gap that attackers walk through.

How much does Microsoft Defender for Office 365 cost?

Microsoft Defender for Office 365 Plan 1 costs from £1.80 per user per month when bought standalone, and it is already included in Microsoft 365 Business Premium at £16.90 per user per month (Microsoft 365 UK pricing). If you are already on Business Premium, you have paid for it — the question is whether it is switched on and tuned.

Plan 1 adds the three controls that matter most against modern phishing:

• Safe Attachments — opens incoming files in an isolated environment before delivery, catching weaponised documents EOP misses.
• Safe Links — rewrites every URL and re-checks it at the moment of click, defeating links that turn malicious after delivery.
• Advanced anti-phishing — impersonation and spoof detection tuned to your domain and named users.

We deploy and harden Defender as part of Microsoft Defender for Business. Buying the licence is step one; configuring policies, exclusions and alerting is where the protection actually comes from.

What does managed email security add — and why does it cost more?

AMVIA's managed email security starts from £5 per user per month on top of your Microsoft 365 licence. You are not paying for different software — Defender and the Barracuda email layer do the filtering — you are paying for the configuration, tuning, monitoring and incident response that turns licences into a defended mailbox estate.

A managed layer typically includes:

• Initial configuration and hardening of Defender for Office 365 policies
• DMARC, DKIM and SPF set up correctly and monitored for failures
• Quarantine review and false-positive management so legitimate mail still flows
• Alerting into AMVIA's UK SOC when something gets through
• Ongoing phishing simulation and reporting

The maths is simple. The average cost of the most disruptive breach for a UK business is £3,550 (DSIT 2025) — and that figure excludes the management time, reputational damage and downtime that follow. A managed email security line of a few pounds per user is cheap insurance against a four-figure incident, before you count the hours your own team would otherwise spend. This is the "one provider, security-first" model: a single accountable team for licensing, configuration and response.

Does DMARC, DKIM and SPF add to the cost?

The DNS records themselves are free. DMARC, DKIM and SPF are open email-authentication standards published as DNS entries, so there is no licence to buy. The cost is expertise: configuring them in enforcement mode without breaking legitimate mail, then monitoring the reports over time.

DMARC is one of the most cost-effective defences against domain spoofing — the technique behind most business email compromise (BEC) fraud aimed at your clients and staff. Overall IC3-reported cybercrime losses attacks increased 33% in 2025 (FBI IC3), and a domain published at `p=reject` makes it far harder for an attacker to impersonate you. The NCSC recommends DMARC for all organisations in its email security guidance. Get it set up properly via our DMARC, DKIM and SPF setup service, then leave it monitored — a misconfigured record silently bins real invoices.

Should you budget for phishing simulation training too?

Yes. No filter catches everything, so training people to spot what slips through is the second line of defence. Phishing simulation platforms typically cost £1–£3 per user per month (market rates as of 2026) and measurably cut click rates on malicious emails over time. Treat it as part of the email security budget, not an optional extra.

Filters and people work together: the technology reduces volume, the training reduces the success rate of the few that land. With phishing identified by 85% of breached UK businesses (Cyber Security Breaches Survey 2025), the human layer is not soft — it is where most real incidents start or stop. Run it through our phishing simulation and training service alongside the managed filtering, and pair both with broader phishing protection.

How should a 25-user business budget for email security?

A practical all-in figure for a typical 25-user UK SME is £150–£200 per month for genuinely managed email security, assuming Microsoft 365 Business Premium is already in place. The exact number depends on how much you run in-house versus hand over.

Worked example for 25 users (ex VAT, per month):

• Defender for Office 365 already included in Business Premium — £0 incremental
• AMVIA managed email security at £5/user — £125
• Phishing simulation at ~£2/user — £50
• DMARC/DKIM/SPF — included in the managed layer

That lands around £175/month for fully managed, monitored email defence with staff testing — against a £3,550 average breach cost that a single successful phishing email can trigger. If you want the full Microsoft 365 security picture beyond email, our Microsoft 365 security pillar covers identity, devices and data alongside mail.