True cost comparison — not just what the pricing page says
Quick Verdict
Mailchimp saves you 100%
Best for Mailchimp
Email marketing platform with automation. Free for 500 contacts, then contact-based pricing creates
Best for Microsoft 365
Microsoft's business productivity suite (Outlook, Teams, Office apps). Per-user pricing where deskto
Email marketing platform with automation. Free for 500 contacts, then contact-ba...
Advertised
$0
/month
True Cost
$113
/month (typical)
Unsubscribed Contacts Count
Mailchimp counts unsubscribed and non-subscribed contacts toward your billing limit. A list of 10K w...
Steep Contact Tier Scaling
Pricing jumps dramatically: 500 contacts = $13.99/mo, 2,500 = $45/mo, 10K = $100/mo, 50K = $350/mo. ...
Pay-As-You-Go Email Credits
Over-limit sends cost extra as email credits. Standard plan allows 12x your contact limit per month....
Advanced Automation Paywall
Free and Essentials include only basic automations. Customer journeys with branching, A/B testing, a...
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...
Mailchimp advertises $0/mo. Microsoft 365 advertises $6/mo.
Mailchimp has 4 documented hidden fees. Microsoft 365 has 4.
Mailchimp confidence: 80%. Microsoft 365 confidence: 84%.
| Metric | Mailchimp | Microsoft 365 | Winner |
|---|---|---|---|
| Advertised Price | $0/mo | $6/mo | Mailchimp |
| True Monthly Cost | $113/mo | $114/mo | Mailchimp |
| Hidden Fee Total | +$113/mo | +$107.5/mo | Microsoft 365 |
| # Hidden Fees | 4 | 4 | Mailchimp |
| Confidence Score | 80% | 84% | Microsoft 365 |
| Pricing Tiers | 4 | 3 | — |
| Affiliate Program | No public affiliate program (discontinued 2022) | No public affiliate program | — |
Mailchimp advertises $0/mo and Microsoft 365 advertises $6/mo. However, when you include hidden fees, Mailchimp has 4 documented hidden fees adding +$113/mo, while Microsoft 365 has 4 hidden fees adding +$107.5/mo. Based on true cost, Mailchimp is typically 100% cheaper.
Mailchimp has 4 documented hidden fees: Unsubscribed Contacts Count, Steep Contact Tier Scaling, Pay-As-You-Go Email Credits, Advanced Automation Paywall. These add approximately +$113/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 Mailchimp if: Email marketing platform with automation. Free for 500 contacts, then contact-based pricing creates . 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. Mailchimp data has a 80% 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.
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