AI Email Assistant Comparison: What $14, $23.50 and $33 Seats Actually Buy

Gemini in Gmail comes inside a $14 Google Business Standard seat. Microsoft sells Business Standard with Copilot for $23.50. Superhuman Business costs $33 and is used with a Gmail or Outlook account you still have to pay for. In this AI email assistant comparison, a 25-seat team pays between $4,200 and $14,100 a year, and the price gap is wider than the feature gap.

AI email assistant comparison: the short answer

If you already pay for Google Workspace Standard, use Gemini in Gmail first, because it costs nothing extra. On Microsoft, buy the $23.50 bundle for people who need mailbox-wide answers and triage. Add Superhuman only for individuals whose inbox speed justifies $396 per seat per year.

That recommendation follows from one structural fact. Google and Microsoft sell the mailbox and the assistant together. Superhuman does not sell a mailbox at all. It is used with a Gmail or Outlook account, so its price is always additive, and its data chain is always longer.

This post covers email only. If your question is Word, Excel and Docs, read the document-focused comparison of Copilot and Gemini seats, which I will not repeat here. Email deserves its own analysis because the inputs are different: you do not choose who writes to you, and every message is third-party content.

I checked every price and policy below against vendor pages on 6 November 2026. I did not run a hands-on test of output quality, and no vendor document I read publishes a comparable accuracy figure. So this is a comparison of cost, gates and commitments. It is not a verdict on which assistant writes the better reply.

AI email assistant pricing: what each seat costs

List prices for email AI differ by a factor of more than 2, and the real comparison depends on whether the price includes a mailbox. All figures below are US list prices per user per month, retrieved 6 November 2026.

Superhuman's monthly figures are inferred from its stated 17% annual discount and match third-party price checks; I could not capture them from its own page. The $18 Copilot Business rate is promotional, listed for 1 July to 31 December 2026, first year only. Enterprise pricing for Superhuman is not public.

Two things in that table should change how you buy. First, the Microsoft bundle is a better deal than the add-on. Microsoft's December 2025 partner notice listed Business Standard plus Copilot Business at $30.50. Its June 2026 notice made Business Standard with Copilot a permanent product at $23.50 from 1 July. That is $7 less per seat, or $84 a year, for the same pairing of plan and assistant.

Second, Superhuman now has a cheap entry point that changes its own pitch. The Email Assistant, announced on 3 November 2026, works inside Gmail or Outlook rather than replacing the client. At $12 it costs less than half of Starter. The launch is days old, so I would treat its feature depth as unproven, and team buyers are told to contact sales.

Check your renewal date before any of this. Microsoft's July 2026 price changes reach existing customers at their next renewal, a sequence worked through in the Microsoft 365 renewal math by SKU.

The enterprise email AI bill for 25 seats, worked through

A 25-seat team is the fairest test size, because it is the largest group that can buy every option here at a public price. The working is simple: seat price, times 25 seats, times 12 months, using annual billing throughout.

The Microsoft and Superhuman rows are not perfectly parallel. Adding Superhuman to a Microsoft mailbox instead of a Google one changes the base price. I could not open a Microsoft page confirming the base Business Standard figure, so I have left that row out rather than guess it.

Now the counterweight. These gaps look large as percentages and small against labour. Superhuman Business costs $396 per seat per year. At an illustrative loaded cost of $50 an hour, it pays for itself at 7.9 hours a year, about 9.5 minutes a week across 50 working weeks. The $9.50 monthly gap between the Microsoft bundle and Google Standard is $114 a year, or about 2.3 hours at that rate. Swap in your own hourly figure.

So my view is that seat price should rarely decide this on its own. The break-even is low enough for all three that the deciding questions are whether the capability reaches your mailbox, whether your admin can control it, and where the content goes. The next three sections cover those in order.

Drafting, triage and search: the AI inbox triage and capability matrix

The three products converge on drafting and separate on triage and search, which is where the licence gates sit. The matrix below reads across from the job to the tier that actually does it.

Drafting is close to a commodity

Every option drafts. Google's February 2026 update says Help me write is in standard plans. Microsoft's Copilot overview lists drafting, thread summaries and coaching tips without the paid add-on. Superhuman's claim is style: it says drafts sound like you. That may matter a great deal to a founder and very little to a support team. I would not pay a premium for drafting alone.

Triage is the least settled job

Google's AI Inbox announcement of 15 October 2026 limits it to US users with EN-US as their language. The same post lists Business Starter as available and then says Starter editions roll out later, so check your own tenant. Microsoft's Outlook FAQ says Prioritize my inbox needs a Copilot licence and supports Tier 1 languages. Microsoft also removed the mobile priority view in February 2026, citing "user feedback and costs". That is a useful reminder that triage features can disappear. Superhuman has the longest list of triage automations, and this is the job where its premium is easiest to defend.

Mailbox search is where Microsoft's free tier stops

Search is the sharpest gate. Google lists AI Overviews in Gmail search for Business Starter, Standard and Plus, for paid users with Gmail set to English. Microsoft says Copilot Chat "can't use organizational data via Microsoft Graph", and is only aware of open content. Asking a question across your mailbox therefore needs the paid licence. Superhuman reserves Ask AI for Business and above, so its $25 Starter seat does not include the feature a buyer may most want.

Enterprise email AI admin controls: who can switch it off

Microsoft has the deepest documented compliance controls for email AI. Google's controls depend heavily on edition, and Superhuman reserves its strongest ones for an unpriced plan. For a head of operations, this section may matter more than the feature matrix.

Google: the switch depends on your edition

Google's feature access page lets admins turn Gemini on or off for Gmail by organisational unit, with the default set to on. But the editions it lists are Enterprise Standard and Plus plus some Education products, and Business editions are not among them. It also warns that users can still reach an app's data through Gemini in other apps. AI Inbox has no admin control at all, in Google's own words. The $14 seat is cheap partly because the governance is thinner, and I would confirm this with Google before a rollout.

Microsoft: the most to work with

Microsoft documents audit records for prompts and responses, and retention through Purview. Sensitivity labels with encryption require EXTRACT and VIEW rights before Copilot can touch content, and Copilot in Outlook cannot read S/MIME or Double Key Encryption mail. Admins also get a toggle for AI providers operating as subprocessors. If your compliance team already runs Purview, this is the strongest argument for paying the difference.

Superhuman: the controls live on the unpriced tier

Superhuman's plans page places single sign-on, the Admin Console, team analytics and advanced controls on Enterprise. I found no documented admin switch that disables AI features, though its help centre refused automated access, so that is an absence in what I could read and not proof. Ask directly. A tool built to be the AI layer may reasonably not offer that switch, but your security reviewer will still ask.

Where email AI sends message content and what it retains

All three vendors say your email does not train outside models by default, so training is the wrong place to look for differences. The differences are in the number of companies involved, the retention commitment and the location. Each cell below links to or summarises the vendor's own terms.

Three details deserve a second read. Microsoft enables Claude models "by default for most customers in commercial cloud (excluding EU/EFTA and UK)", and those models are excluded from the EU Data Boundary. If you assumed a Microsoft-only data chain, check that toggle today. The separate rules for buyers in those regions are covered in what EU and India buyers demand on AI data residency.

Superhuman's wording also needs care. Its Email Assistant FAQ says email is "never used to train external AI models", which is narrower than never used to train any model. Its privacy policy says it trains its own models subject to a user control, while organisation accounts fall under the contract. That business agreement does prohibit training on customer data without written consent. So buy on the contract, not on a personal sign-up. Its DPA also makes 30-day notice of new subprocessors conditional on opting in through a form, so opt in on day one.

Deletion is the weakest area across all three, and it is hard to verify. Purview's own documentation warns that messages visible in the app are not an accurate reflection of what is retained. For the wider picture, see the ranked comparison of AI data retention promises, and for contract wording, the seven DPA clauses worth rewriting.

Inbound email makes AI inbox triage an attack surface

All three products have a public record of a researcher using a hostile email against the assistant, and that is the risk most feature comparisons skip. Any stranger can place text in front of your email AI. That is not true of a document assistant.

• Microsoft 365 Copilot, June 2025. EchoLeak, CVE-2025-32711, rated CVSS 9.3, began with an email to an Outlook inbox, according to reporting on the advisory. Microsoft addressed it, and there was no evidence of exploitation in the wild.
• Gemini for Workspace, July 2025. 0DIN showed hidden text in an email making "Summarize this email" append a fake security warning with a phone number. No links or attachments were needed.
• Superhuman, January 2026. PromptArmor showed an injected email pushing the assistant to send the contents of other messages to an attacker's Google Form. The email could sit unopened in the inbox. PromptArmor credits Superhuman with remediating at "incident pace", with an initial patch 3 days after the report.

Do not read this as a ranking. These are disclosed research findings, not incident rates, and all three were addressed or mitigated to differing public detail. 0DIN said the technique remained viable at publication. What I take from them is a buying criterion: the more of your inbox an assistant can read and the more it can do, the more a single hostile email can reach. The general problem is covered in the piece on prompt injection and agent security. Superhuman's statement that its Email Assistant "doesn't send email without your permission" is the right kind of limit to ask every vendor about.

Where this comparison is weakest

The largest weakness is that this post compares documents, not output. A seat that drafts badly is expensive at any price, and I have measured nothing about quality or time saved. The break-even arithmetic above shows what you would need to believe, not whether it is true.

The case for Superhuman that this framing undersells

Its premium buys an opinionated inbox and automations, not just a model. A partner or founder who lives in email may recover the $396 in a week or two, and neither suite vendor's bundled feature is built for that person. If you are buying for 5 people like that, the 25-seat cap and the governance gaps barely apply. In that case, my default recommendation is simply wrong.

Prices and gates here will move quickly

AI Inbox is weeks old, Email Assistant is days old, and Microsoft already removed one priority view this year. Several facts also rest on partial evidence. The Superhuman Suite page viewed from India showed Mail starting at Business rather than Starter, so regional packaging may differ from the US Mail plans page. Google's $14 annual reading is inferred from a toggle. Microsoft's base Business Standard price could not be confirmed from a page I opened, which is why this analysis uses the bundle.

Frequently asked questions

Where to start: price the seat you already own

Begin with the assistant you have already paid for. Have 3 of your heaviest email users spend one week on Gemini in Gmail or Copilot Chat in Outlook, and log each task the tool could not reach. If that list is mostly mailbox-wide questions, a Microsoft shop has its case for the bundle. If it is mostly sorting and speed, trial Superhuman for those 3 people only.

Then send every vendor on your shortlist the same 3 questions in writing. How long is email content retained after AI processing, and by which companies? Which admin control turns the AI features off for one group? What stops text in an inbound email from instructing the assistant to read or send other mail? The answers you get will separate these products faster than any feature grid, including the one above.

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