Every "Google Workspace vs Microsoft 365" article you have read is a feature comparison written by someone with an opinion. This one is different: it is a census. Every domain that receives email publishes its choice of mailbox provider in a public DNS record — the MX record — and we scan those records for the Tranco top-1M domains every night, using daily OpenINTEL snapshots going back to January 2016. That is 192 snapshots of what a million organisations actually chose, not what they say in surveys.
As of the 2026-07-05 snapshot, 664,715 of the top-1M domains have an MX record. Of those, 21.75% point to Google Workspace and 16.68% point to Microsoft 365. Together, two companies receive the business email of 38.4% of the world's top domains.
The ten-year scoreboard
In January 2016 this was not a close race. Google Workspace (then G Suite) already held 15.4% of mail-receiving top domains; Microsoft 365 held just 4.46%. Google had won the first decade of cloud email decisively — startups, agencies, and web-native companies defaulted to Gmail-for-business and never looked back.
The second decade looks different. By 2022 Microsoft had climbed to 12.37% while Google reached 20.11%. And since 2022 the momentum has flipped outright: Microsoft added +4.31 percentage points to reach 16.68%, while Google added +1.64 to reach 21.75%. That is 2.6× faster growth for Microsoft over the last four years — a trend we unpack in a dedicated analysis. Google still leads, but the gap is 5.07 points and shrinking.
Where the growth came from
Neither suite is primarily stealing customers from the other. The donor pool is self-hosted email: domains running their own Postfix, Exim, or Exchange servers fell from 42.76% of the top-1M in 2016 to 22.53% in 2026. Every year, another slice of organisations decides that running a mail server is not their core business, and nearly all of that slice lands on one of the two suites.
The choice between them follows a recognisable pattern, visible when you correlate mailbox provider with the rest of a domain's DNS footprint:
- Google Workspace skews web-native. Startups, SaaS companies, agencies, and anyone whose workflow already lives in a browser. The onboarding is self-serve and the admin surface is small.
- Microsoft 365 skews enterprise and regulated. Domains behind Microsoft disproportionately also show security gateways, compliance tooling, and signature-management SaaS in their DNS — the fingerprints of IT departments, procurement, and Active Directory estates.
Neither pattern is a rule. Plenty of 10,000-seat companies run Google, and plenty of three-person consultancies run Microsoft 365 because their clients do. But the aggregate skew is consistent across the dataset.
What the numbers mean if you are choosing today
| Signal | Google Workspace | Microsoft 365 |
|---|---|---|
| Share of top-1M MX domains (2026) | 21.75% | 16.68% |
| Share in 2016 | 15.4% | 4.46% |
| Growth since 2022 | +1.64 pp | +4.31 pp |
| Typical adopter profile | Web-native, startup, SMB | Enterprise, regulated, AD-centric |
A market-share census cannot tell you which product fits your team. What it can tell you:
- Both choices are safe. At 38.4% combined share and rising, neither platform is going anywhere. Ecosystem risk — the thing that killed registrar-bundled mail and is draining self-hosting — does not apply here.
- Your counterparties are increasingly on these two filters. If you send email for a living — sales, marketing, transactional — roughly four in ten top-domain recipients are judged by either Gmail's or Microsoft's spam filter. Whichever suite you pick for receiving, you will spend your sending career optimising for both.
- The default is shifting with company size. If you expect to sell into enterprises, being on Microsoft 365 yourself removes some friction (calendar invites, Teams meetings, tenant-to-tenant sharing). If your world is startups, Google remains the lingua franca.
Both series update every night. The current split, plus 30+ other mailbox and ESP providers, is published in our daily email infrastructure report — including machine-readable JSON if you want to chart it yourself.
One practical consequence founders miss
Whichever suite you choose, your domain's outbound reputation starts from zero. The suite gives you excellent inbound filtering on day one, but your SPF, DKIM, and DMARC records — and how the other 38% of the duopoly's filters see your new domain — are your problem. A common founder failure mode is signing up for Workspace, firing off 200 outreach emails in week one, and quietly landing in spam at every Microsoft-hosted prospect. Before any meaningful send, verify where your mail actually lands with an inbox placement test across both ecosystems — the two filters disagree with each other far more often than people expect.