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Productivity · head to head

Fastmail vs Proton Mail

Fastmail logo

Fastmail

Productivity

Paid email hosting with custom domains, calendar and contacts, run without ad-based revenue

From
$3/month
Rated
-
Full reviewWebsite
Proton Mail logo

Proton Mail

Cybersecurity

Secure email that protects your privacy

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Proton Mail has a free tier, so it costs nothing to try first.
  • Each has a real cost: Fastmail it does not provide end-to-end encryption by default, so users specifically wanting zero-knowledge mail should compare it against Proton Mail or Tuta rather than assume parity.; Proton Mail paid plan pricing not displayed on vendor site
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Fastmail and Proton Mail actually diverge.

Attributes where Fastmail and Proton Mail differ
AttributeFastmailProton Mail
Starting price$3/monthFree
Pricing modelPer user per monthfreemium
Free tierNoYes
PlatformsWeb, iOS, Android, macOS, WindowsWeb
CategoryProductivityCybersecurity

Identical on both: user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Fastmail

  • Custom domain hosting
  • Masked email
  • Unlimited aliases
  • Integrated calendar and contacts
  • Migration tools
  • JMAP support

Only in Proton Mail

Nothing recorded that Fastmail does not also cover.

What people use each for

The jobs each tool is most often brought in to do.

Fastmail

  • Someone who wants their email address tied to a domain they own rather than a free provider they do notnot Proton Mail
  • A small business wanting hosted mail on its own domain without running mail server infrastructurenot Proton Mail
  • A person leaving Gmail specifically to stop an ad-funded provider processing their mailnot Proton Mail
  • A household migrating several accounts to one paid provider with shared billingnot Proton Mail

Proton Mail

  • Encrypted email communicationnot Fastmail
  • Privacy-focused email servicenot Fastmail
  • Family email protectionnot Fastmail

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Fastmail

  • It does not provide end-to-end encryption by default, so users specifically wanting zero-knowledge mail should compare it against Proton Mail or Tuta rather than assume parity.
  • Moving to Fastmail is a real migration with DNS changes for a custom domain, unlike installing a client such as Spark or Bluemail over an existing account.
  • There is no free tier at all, so a user just wanting to try it commits to a paid trial rather than a permanently free option.
  • Storage limits on the entry Basic plan are modest next to the free allowance Gmail gives, and heavy attachment users will need Standard or above.
  • Being based in Australia means it falls under Australian data access law, which some privacy-focused buyers weigh differently from Swiss or German jurisdictions used by Proton Mail and Tuta.

Proton Mail

  • Paid plan pricing not displayed on vendor site
  • Free tier limited to 1 GB storage
  • Free tier limited to single email address

Pricing, plan by plan

Fastmail

$3/month
  • Basic$3/month
    • 6GB storage
    • No custom domain support
    • Core mail, calendar and contacts
  • Standard$5/month
    • 60GB storage
    • Custom domain support
    • Masked email and aliases
  • Professional$9/month
    • 150GB storage
    • Multiple custom domains
    • Priority support

Proton Mail

Free

No published plan breakdown. See the Proton Mail review.

Which should you pick?

Choose Fastmail if

  • You need custom domain hosting.
  • You work on Web, iOS, Android, macOS, Windows.
  • You also want masked email.
Fastmail review

Choose Proton Mail if

  • You want to start without paying.
Proton Mail review

Questions people ask

Is Fastmail or Proton Mail better?
Neither clearly leads. Fastmail starts at $3/month and Proton Mail at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Fastmail or Proton Mail?
Proton Mail has a free tier; the other does not. Paid plans start at $3/month for Fastmail and Free for Proton Mail.
Does Fastmail or Proton Mail run on more platforms?
Fastmail runs on Web, iOS, Android, macOS, Windows. Proton Mail runs on Web.
Can I use Proton Mail for free?
Yes. Proton Mail has a free tier, so you can try it without paying. Fastmail starts at $3/month.
What is Fastmail best used for?
Fastmail is most often used for someone who wants their email address tied to a domain they own rather than a free provider they do not, a small business wanting hosted mail on its own domain without running mail server infrastructure, a person leaving gmail specifically to stop an ad-funded provider processing their mail, a household migrating several accounts to one paid provider with shared billing. Of those, someone who wants their email address tied to a domain they own rather than a free provider they do not and a small business wanting hosted mail on its own domain without running mail server infrastructure are not what Proton Mail is typically brought in for.
What can Fastmail do that Proton Mail cannot?
Fastmail covers Custom domain hosting, Masked email, Unlimited aliases, Integrated calendar and contacts.

Answered from the vendors’ own pages

Fastmail: Is Fastmail a client like Spark, or does it host my email?

It hosts the mailbox itself; there is no separate provider underneath it the way Spark sits over Gmail.

Proton Mail: Is there a free version of Proton Mail?

Yes, Proton Mail offers a free plan with 1 GB storage, 1 encrypted email address, and basic features like folders, labels, and filters.

Source
Fastmail: Does Fastmail offer end-to-end encryption?

Not by default in the way Proton Mail or Tuta do; its privacy position rests on being subscription-funded rather than ad-funded.

Proton Mail: What does the Mail Plus plan include?

Mail Plus includes 15 GB storage, 10 encrypted email addresses, support for 1 custom domain, 10 hide-my-email aliases, priority support, and access to Proton Calendar.

Source
Fastmail: Can I use my own domain?

Yes, from the Standard plan up, with full alias and masked email support.

Proton Mail: What is included in Proton Unlimited?

Proton Unlimited provides 500 GB storage, 15 email addresses, 3 custom domains, unlimited hide-my-email aliases, access to Mail, Calendar, VPN, Drive, and Pass, plus dedicated support.

Source
Proton Mail: Does Proton Mail offer a money-back guarantee?

Yes, Proton Mail provides a 30-day money-back guarantee for paid plans.

Source
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