Microsoft Defender for Office 365 Hidden Costs 2026
What they don't show you on the pricing page
Microsoft Defender for Office 365 costs $2 to $5 per user/month as of May 2026. Pricing depends on your chosen tier, contract length, and negotiated discounts.
Use the interactive pricing calculator to estimate your exact cost based on team size and requirements.
- Free tier: No free tier available
Microsoft Defender for Office 365 true cost runs NaN% above the listed $2-$5/user/month price as of May 2026. For a 25-person team, expect ~$NaN in year-one costs vs the $1,050 base license. Key hidden costs: microsoft 365 e3/e5 base subscription required: $36-57/user/month, audit log retention beyond 1 year: requires e5 compliance add-on, advanced compliance features: e5 compliance add-on at $12/user/month. Verified from 5 sources by CostBench.
Example: True Cost for 25 Users
| License (25 × $3.5 × 12) | $1,050/yr |
| Implementation (one-time) | +$15,000–$50,000 |
| Premium Support (20%) | +$210/yr |
| Training (25 × $500) | +$12,500 |
| Admin (part-time) | +$15,000–$25,000/yr |
| Estimated Year 1 Total | ~$NaN |