These three all land within about $4 of each other per user per month, which makes this one of the rare comparisons where price genuinely isn't the deciding factor — what you're actually choosing between is three different definitions of what "business email" should include.
Fastmail is the cheapest, around $3–5/user/month, and it's cheap because it doesn't try to be anything but email, calendar and contacts, done well. No AI upsell, no bundled office suite — just a fast, standards-based mail client that a lot of people who've used everything else quietly prefer.
| Service | Entry plan | Price/user/mo | What you get |
|---|---|---|---|
| Fastmail | Basic / Standard | ~$3–5 | fast, standards-based email + calendar + contacts |
| Proton Mail | Mail Essentials | ~$6.99 | E2E-encrypted mail, custom domain, aliases |
| Google Workspace | Business Starter | ~$7 | Gmail + Docs/Sheets/Slides + Drive + Meet + Gemini |
Proton Mail sits a couple of dollars above that, and the extra buys something Fastmail doesn't offer at all: end-to-end encryption by default, Swiss jurisdiction, and built-in email aliases. Step up to Proton's Business "standard" tier, roughly $12.99/user/month, and the rest of the Proton apps come with it — Drive, VPN, Calendar, Pass — which starts to look less like an email upgrade and more like a whole privacy-focused office replacement.
Google Workspace costs about the same as Proton's entry tier but is solving an entirely different problem: it assumes you need documents, spreadsheets, shared drives and video calls as much as you need email, and this year it folded Gemini into the mid tier at no extra charge, which meaningfully improved its value without moving the price. That's arguably the single biggest change in this category this year — AI access that used to cost extra now doesn't, at least on Google's side.
The honest way to choose here isn't about price at all, since the numbers are close enough not to matter much. Pick Fastmail if email, calendar and contacts genuinely are the whole job and you don't want anything else bundled in. Pick Google Workspace the moment shared documents and video calls are as central to how your team works as email is — which, for most small businesses, they are. Pick Proton Mail specifically when encryption and jurisdiction are requirements, not preferences — a real compliance need, a client who asks, a personal line you won't cross — because that's the one thing neither of the other two is built around.