How Much Does Email Security Cost for a Small Business?

Exchange Online Protection, included with all Microsoft 365 plans, provides basic anti-spam and anti-malware filtering. However, it lacks the advanced anti-phishing, safe attachments, and link detonation capabilities of Defender for Office 365. 85% of businesses that experienced a breach identified phishing as the attack vector (DSIT 2025), making the additional protection layers well worth the modest per-user cost.

DMARC is a free DNS-based standard that prevents attackers from spoofing your domain in phishing emails. Implementing it costs nothing for the DNS records themselves, though proper configuration and monitoring require expertise. BEC attacks increased 33% in 2025 (FBI IC3 Report), and DMARC is one of the most cost-effective defences against impersonation fraud targeting your clients and staff.

Yes. Even the best email filters cannot catch every threat, so training staff to recognise phishing is a critical second layer. The average cost of the most disruptive breach is £3,550 (DSIT 2025), and human error remains the trigger in most successful phishing attacks. Simulation platforms typically cost £1-£3 per user per month and measurably reduce click rates on malicious emails over time.