TL;DR
- Choose Google Workspace when Gmail, Drive and Google identity already run the business and you want straightforward per-user administration. Business Starter lists $7/user/month on annual commitment.
- Choose Microsoft 365 when Outlook, Exchange and Entra ID already govern access, retention and security. Business Basic also lists $7/user/month paid yearly in the US; Exchange Online Plan 1 lists $4 for a mailbox-only alternative.
- Neither service is a dedicated bulk outreach platform. Microsoft says Exchange Online is not designed for bulk mail; Google prohibits spam and unsolicited commercial mail through Gmail. Daily limits are enforcement ceilings, not a suggested campaign quota.
- Twenty named mailboxes cost about $140/month equivalent on either Starter or Business Basic at current US annual rates, before tax, domains and sequencer fees. The decision is mainly about administration and policy fit, not a deliverability shortcut.
What the provider choice decides
A mailbox suite supplies user identity, mail hosting and administration. A sequencer supplies campaign steps, mailbox rotation and reply handling. A dedicated sending service supplies a different delivery system. These are separate jobs even where one vendor bundles or connects several.
Workspace versus Microsoft 365 changes the identity directory, admin console, collaboration bundle, mailbox storage, security controls, licence price and connection path to outreach software. It does not guarantee inbox placement. Authentication, recipient expectations, list quality, volume, complaints and receiving-provider decisions still matter.
For an agency, decide who owns each domain and tenant, controls DNS, can recover accounts and receives the data at termination. Connect sequencers through approved OAuth or application access where available; avoid shared employee passwords. Keep client domains and suppression lists distinct where the contract or law requires it.
Plans and 20-mailbox cost
| Mailbox setup | Published price basis | 20-mailbox subtotal | What it excludes |
|---|---|---|---|
| Google Workspace Business Starter | $7/user/month annual; 30 GB pooled storage/user | $140/month equivalent | Domains, sequencer, tax, separate client tenants |
| Google Workspace Business Standard | $14/user/month annual; 2 TB pooled storage/user | $280/month equivalent | Same exclusions; storage/collaboration may be unnecessary for sending accounts |
| Microsoft 365 Business Basic | $7/user/month paid yearly; 50 GB Exchange mailbox, 1 TB OneDrive/user | $140/month equivalent | Domains, sequencer, tax, additional security products |
| Exchange Online Plan 1 | $4/user/month paid yearly in US comparison; 50 GB mailbox | $80/month equivalent | Office and collaboration features in Business Basic; regional terms |
These US public prices were checked 29 September 2026 before tax. Google's current page includes an introductory offer for eligible new users; this table uses renewal rates. Microsoft prices vary by region and term. Twenty licences assume twenty separately licensed people/mailboxes. Aliases and shared mailboxes are not automatically equivalent to independent sending identities.
Add DNS and domains, provisioning, validation, sequencer subscriptions, administration and reply coverage. A cheap mailbox plan does not establish that a proposed outreach use is permitted.
Illustrative labour model, not a vendor quote: assume an agency provisions 20 named accounts, values administration time at $50/hour, and has four leavers or role changes each year. In an existing Microsoft tenant, assume two hours to set up the accounts and 30 minutes a week for access, integration and reply checks. In a new Google tenant, assume four initial hours and one hour a week while the team establishes its admin process. Allow 30 minutes per offboarding event on either service. That produces $100 versus $200 initial labour; ongoing labour is about $117 versus $225 a month (52 weeks/12 months plus the annual offboarding allowance). Including the $140 licence subtotal, the illustrative monthly operating figure is about $257 Microsoft and $365 Google, plus one-time setup, domains, taxes and sequencer. Reverse the tenant familiarity and the labour advantage can reverse. This is a way to price the decision, not a measured claim about either console's efficiency.
Google Workspace
Google's Business editions page lists Starter at $7/user/month on annual or fixed-term plans ($8.40 flexible), Standard at $14 ($16.80 flexible), and Plus at $22 ($26.40 flexible). Starter provides 30 GB pooled storage per user, Standard 2 TB and Plus 5 TB. Business editions support up to 300 users; larger organisations need Enterprise.
Workspace suits a team already using Gmail, Drive and Google identity. The Admin console provides the familiar place to provision named users, apply organisation controls and retire access. Standard may be justified for storage and broader collaboration, but upgrading does not create a higher permitted cold-outreach quota.
Google's Gmail Program Policies prohibit using Gmail to distribute spam or unsolicited commercial mail. Its sender guidelines apply to Workspace messages sent to personal Gmail accounts. If the planned use conflicts with the terms or applicable law, change the use or choose a suitable service; don't treat a numeric daily cap as permission.
Microsoft 365
Microsoft's Exchange and business-plan comparison lists Business Basic at $7/user/month paid yearly in the US with a 50 GB primary Exchange mailbox and 1 TB cloud storage. Exchange Online Plan 1 lists $4/user/month yearly and a 50 GB mailbox. Business Standard adds desktop Office apps; compare that bundle only when staff need it.
Microsoft is a natural fit when Entra ID, Outlook, Defender, retention and Microsoft administration already govern the organisation. Outbound spam policies and reporting provide useful administration for legitimate mail. They also mean misconfiguration or suspicious activity can cause restrictions that resemble a deliverability problem.
Microsoft explicitly says Exchange Online is not designed for bulk email and recommends specialist providers for high-volume sending. It may throttle, restrict a sender or route suspicious traffic through a high-risk delivery pool. Configurable policy controls do not turn the service into an unrestricted campaign server.
Sending rules and limits
Microsoft documents a 10,000-recipient per-mailbox rolling 24-hour rate limit and 30 messages per minute. Tenant-level external-recipient and outbound-spam controls also apply. See Exchange Online limits and Microsoft's sending-limit guide. These figures are service ceilings, not safe cold-email targets.
Google's Workspace Gmail limit table lists 2,000 messages per paid user over a rolling 24 hours, 10,000 total recipients, 3,000 external recipients and 2,000 unique external recipients. Trial accounts have a 500-message ceiling and 500 unique external recipients, with additional trial restrictions; moving to a paid account can require a payment threshold before higher limits take effect. Per-message limits differ by sending path: the table lists 2,000 recipients for Gmail (maximum 500 external), 500 through the Gmail API and 100 through SMTP by POP or IMAP. Aliases, delegated users and vacation replies count against user limits.
These measures are not equivalent to Microsoft's 10,000-recipient rolling limit and 30-message-per-minute limit. Google has separate message, unique-recipient, external-recipient and transport ceilings; Microsoft also has tenant and outbound-spam controls. In both products, limits can change or be reduced for account risk. Trial and relay limits are not interchangeable with ordinary paid-user Gmail sending. None of these figures is a recommended cold-email volume.
For predictable campaign operations, evaluate a purpose-built service and its terms. Keep transactional and employee mail appropriately separated. SPF, DKIM and DMARC plus a monitored reply address are baseline setup, not a route around provider policies.
A practical mailbox design
Maintain a register of person, mailbox, domain, tenant owner, recovery contact, connected sequencer, permitted client and retirement date. For Google, record the Workspace super-admin and authorised OAuth application, check the app's scopes, then revoke its grant before retiring the user. For Microsoft, record the Entra administrator, Exchange mailbox licence and application consent; disable sign-in, revoke sessions/app access, and complete the organisation's retention/export procedure. These are different console paths to the same ownership control. Do not delete an account before preserving replies needed for client handoff or a lawful retention obligation. Test a small group to verify sending, reply arrival and CRM matching. Keep personal employee accounts out of shared campaign rotation.
A multi-client agency can place client domains in separate tenants or centralise them in one agency tenant. Separate tenants make ownership and transfer clearer but add administration. A central tenant streamlines provisioning and billing but increases the impact of a role or integration error. Neither provider's basic licence proves client isolation. Test restricted roles and account discovery.
Rehearse exit: remove a test user, revoke app access, transfer DNS ownership and export required records. Confirm who retains the domain, mailbox data, replies and suppression history. Clients should not depend on a former contractor's recovery address or super-admin account.
Which should you choose?
Choose Google Workspace if Gmail and Google identity are the existing standard. Choose Microsoft 365 if the organisation already runs identity, security and records through Microsoft. Their US annual entry prices currently match; choose the stack that keeps account ownership and administration clear.
Do not choose either because its cap looks generous. Microsoft says Exchange Online is not designed for bulk sending, and Google bars spam and unsolicited commercial mail. First establish that the planned contact is allowed by provider terms and relevant law. Then select a specialist sending platform if required.
For a setup checklist covering authentication and ongoing mailbox review, use the cold email deliverability checklist after confirming the provider permits the intended use.
FAQ
Which provider improves deliverability?
Neither guarantees placement. Select based on identity administration, security, mailbox access and collaboration needs. Authentication, reputation, complaints, volume and recipient expectations influence receiving systems.
What do 20 mailboxes cost?
At current US annual-equivalent prices, 20 Workspace Starter or Microsoft 365 Business Basic users are each about $140/month before tax. Exchange Online Plan 1 lists $80/month for 20 users but excludes Business Basic's productivity bundle. Domains and sequencer costs are extra.
Can Microsoft 365 send bulk cold email?
Microsoft says Exchange Online is not designed for bulk email and recommends a specialist provider at high volume. The 10,000-recipient service limit is not an endorsement or safe target. Check the intended use against current terms.
Why do Workspace limit figures differ between articles?
They may count unique recipients, total recipients, external recipients, messages, transactions, relay use or trial accounts. Consult Google's current admin documentation for your sending path.
Should an agency put all clients in one tenant?
Choose based on domain/data ownership and required exit boundaries. Central tenancy simplifies administration but concentrates access; separate tenants simplify transfer but add work. Test least-privilege access, app revocation and export.
Does adding mailboxes increase permission to send?
It adds licensed mailboxes, not permission to send unwanted or prohibited messages. Provider policy, jurisdiction, reputation and recipient feedback still apply. Do not multiply a cap to set campaign volume.
