E5 costs substantially more than E3 per user per month. Across a few hundred seats that is a material budget line, and it deserves a harder assessment than most organizations give it.
What E5 adds
Security
- Defender for Endpoint Plan 2 — endpoint detection and response, threat hunting, automated investigation
- Defender for Identity — detection of on-premises Active Directory attacks
- Defender for Cloud Apps — cloud access security broker and shadow IT discovery
- Defender for Office 365 Plan 2 — attack simulation, automated response, threat tracking
- Microsoft Entra ID P2 — identity protection, privileged identity management, access reviews
Compliance
- Purview eDiscovery Premium — custodian management, review sets, analytics
- Purview Insider Risk Management
- Purview Communication Compliance
- Advanced Audit with extended retention
- Customer Lockbox and Customer Key
Other
- Power BI Pro per user
- Teams Phone system
- Audio Conferencing
The question that decides it
Not whether these capabilities are valuable — they are. The question is whether anyone will operate them.
Defender for Endpoint P2 generates alerts. Identity Protection flags risky sign-ins. Insider Risk Management surfaces behavioural signals. Every one of those outputs requires a human to triage it, decide, and act. Without that person, E5 produces a dashboard nobody opens and an invoice that arrives regardless.
When E5 clearly makes sense
- You have a security operations function, internal or outsourced, that will act on alerts
- Regulatory obligations require the advanced compliance tooling specifically
- You are replacing third-party tools whose combined cost approaches the difference
- Teams Phone would replace an existing telephony contract
- Power BI Pro is already licensed separately across a large share of users
That fourth and fifth point deserve emphasis. If you already pay for Power BI Pro, a phone system, and a third-party CASB, the incremental cost of E5 is far smaller than the headline difference — and sometimes negative.
When E3 plus targeted add-ons is better
You do not have to choose between the two plans wholesale. E3 with selectively purchased add-ons frequently lands closer to what an organization actually needs.
A common structure: E3 across the organization, Entra ID P2 for administrators and executives, Defender for Endpoint P2 on servers and high-risk endpoints, and eDiscovery Premium only if litigation is a realistic prospect. That covers most of the genuine risk at a fraction of a full E5 uplift.
Consider a mixed estate
Licensing is per user. Executives, finance staff, and administrators — the accounts most likely to be targeted and most damaging if compromised — can sit on E5 while the rest of the organization runs E3. Risk is not distributed evenly across your headcount, and licensing does not need to be either.