True cost comparison — not just what the pricing page says
Quick Verdict
Klaviyo saves you 100%
Best for Klaviyo
E-commerce email and SMS marketing platform. Free for 250 contacts, then contact-based pricing that
Best for Microsoft 365
Microsoft's business productivity suite (Outlook, Teams, Office apps). Per-user pricing where deskto
E-commerce email and SMS marketing platform. Free for 250 contacts, then contact...
Advertised
$0
/month
True Cost
$205
/month (typical)
Steep Contact-Based Scaling
Free for 250 contacts. Then: 1K = $30/mo, 5K = $100/mo, 10K = $150/mo, 25K = $400/mo, 50K = $720/mo....
SMS Credits Charged Separately
SMS marketing requires separate credit purchases. US SMS: $0.01-$0.015/message. 10K SMS/mo = $100-15...
Email Send Limits Per Tier
Email sends are capped at 10x your contact limit on most plans. Exceeding requires upgrading to a hi...
Microsoft's business productivity suite (Outlook, Teams, Office apps). Per-user ...
Advertised
$6
/month
True Cost
$114
/month (typical)
Desktop Apps Require Business Standard
Business Basic ($6/user/mo) only includes web and mobile Office apps. Desktop Word, Excel, PowerPoin...
Copilot AI Add-On
Microsoft 365 Copilot AI is $30/user/mo — separate from all base plans. For 50 users, Copilot alone ...
Compliance Features Require E5
Advanced compliance (eDiscovery, DLP, Information Barriers, Insider Risk Management) require Enterpr...
Teams Phone Add-On
Microsoft Teams Phone System for PSTN calling is not included in any standard plan. Teams Phone Stan...
Klaviyo advertises $0/mo. Microsoft 365 advertises $6/mo.
Klaviyo has 3 documented hidden fees. Microsoft 365 has 4.
Klaviyo confidence: 78%. Microsoft 365 confidence: 84%.
| Metric | Klaviyo | Microsoft 365 | Winner |
|---|---|---|---|
| Advertised Price | $0/mo | $6/mo | Klaviyo |
| True Monthly Cost | $205/mo | $114/mo | Microsoft 365 |
| Hidden Fee Total | +$205/mo | +$107.5/mo | Microsoft 365 |
| # Hidden Fees | 3 | 4 | Klaviyo |
| Confidence Score | 78% | 84% | Microsoft 365 |
| Pricing Tiers | 3 | 3 | — |
| Affiliate Program | None | No public affiliate program | — |
Klaviyo advertises $0/mo and Microsoft 365 advertises $6/mo. However, when you include hidden fees, Klaviyo has 3 documented hidden fees adding +$205/mo, while Microsoft 365 has 4 hidden fees adding +$107.5/mo. Based on true cost, Klaviyo is typically 100% cheaper.
Klaviyo has 3 documented hidden fees: Steep Contact-Based Scaling, SMS Credits Charged Separately, Email Send Limits Per Tier. These add approximately +$205/mo on top of the $0/mo advertised price.
Microsoft 365 has 4 documented hidden fees: Desktop Apps Require Business Standard, Copilot AI Add-On, Compliance Features Require E5, Teams Phone Add-On. These add approximately +$107.5/mo on top of the $6/mo advertised price.
Choose Klaviyo if: E-commerce email and SMS marketing platform. Free for 250 contacts, then contact-based pricing that . Choose Microsoft 365 if: Microsoft's business productivity suite (Outlook, Teams, Office apps). Per-user pricing where deskto. The right choice depends on your team size, usage volume, and which features you need most.
This comparison is based on manual research of official pricing pages, terms of service, and user reports. Klaviyo data has a 78% confidence score and Microsoft 365 has 84%. Prices were last verified in April 2026. For the most accurate estimate, enter your specific usage in our calculator.
Enter your usage to see personalized pricing for both tools
Use Free Calculator