What an accounting firm needs from email signature software
Most "best email signature software" lists are written for marketing teams that want banners and click tracking. An accounting firm buys for different reasons. Clients judge a firm partly on how consistent and careful its email looks, the signature carries credentials that state boards regulate, and the footer is where the firm tells clients how it handles sensitive data. Four requirements decide the choice:
- Credentials filled per person. "CPA" belongs only after the names of licensed CPAs, and state boards of accountancy regulate who can use the title. A template that pulls credentials from the directory stops a staff accountant from adding it early and stops a departed partner's title from living on in someone's copied signature.
- One approved confidentiality notice. Firms want a single wording signed off by the managing partner, not a dozen variants.
- Seasonal staff without a bigger bill. A firm that adds eight preparers from January to April needs those mailboxes signed on day one, and ideally without the subscription climbing for four months.
- Coverage on phones and the web. Partners answer clients from their phones. A signature that only exists on the office desktop is not a firm standard.
Email signature software prices at 25 and 50 mailboxes
The table uses each vendor's published US list prices, checked on 19 September 2026, and annual billing unless noted. Exclaimer and CodeTwo both require a minimum of 10 users. Prices change, so confirm on the vendor's own pricing page before you buy.
| Product and plan | Pricing model | 25 mailboxes a month | 50 mailboxes a month |
|---|---|---|---|
| Exclaimer Starter | $0.90 per user, one template | $22.50 | $45.00 |
| Exclaimer Standard | $1.45 per user, unlimited templates, scheduling | $36.25 | $72.50 |
| Exclaimer Pro | $1.75 per user, adds analytics and CRM sync | $43.75 | $87.50 |
| CodeTwo Email Signatures 365 | $1.22 per user at 25, $1.21 at 50 | $30.50 | $60.50 |
| AutoSignature Team | Flat, up to 25 mailboxes | $79 yearly, $99 monthly | Not eligible |
| AutoSignature Business | Flat, 26 to 150 mailboxes | Not needed | $239 yearly, $299 monthly |
| Microsoft 365 mail flow rule | Included in your license | $0 | $0 |
The honest reading: on list price alone, per-seat tools are cheaper for a small firm, and a mail flow rule is free. If a 25-person firm on Microsoft 365 wants one signature, one disclaimer and nothing else, Exclaimer Starter or CodeTwo will cost less than we do, and you should buy one of them.
The picture changes with seasonal hiring and with what you need included. A per-seat bill for 50 mailboxes moves every time headcount does, and banner campaigns, several templates or analytics often sit in a higher tier. A flat plan is one number for the year: the Business plan costs the same whether you run 60 mailboxes in July or 140 in March. Full plan limits are on the email signature software pricing page.
Which email signature software to buy, by type of firm
Solo practitioners and firms under 10 people
You are below the 10-user minimum of both per-seat vendors. A well-built HTML signature set by hand in each mailbox is usually enough at this size, and the Microsoft 365 mail flow rule covers the disclaimer. Revisit the question when you hire the tenth person or open a second office.
Firms of 10 to 25 on Microsoft 365, one office
CodeTwo is a strong fit: it is built around Microsoft 365, its per-user price includes unlimited templates and banners, and at this size it costs roughly $30 a month. Exclaimer Starter is cheaper if one template really is enough. Choose AutoSignature Team at $79 a month billed yearly if the firm also has Google Workspace mailboxes, if you want the short signature on replies, or if you want marketing and IT kept apart with a rollback on every change.
Firms of 25 to 150 with seasonal preparers or several offices
This is where a flat plan earns its price. Disclaimer rules by office, a separate template for seasonal preparers that is applied by group and removed when they leave, a year-end tax planning banner for the client-facing partners only, and a bill that does not move in tax season. The Business plan covers all of it. The details of how Office 365 signatures are applied are on the Office 365 email signature management page.
Firms that also do legal or advisory work
Multi-discipline practices often need attorney and CPA signatures side by side, each with its own disclaimer. The same rules engine handles both; see how it works for attorneys on the law firm email signature software page.
Disclaimers a CPA firm should and should not carry
Three lines come up on almost every accounting firm signature. Two are worth keeping.
- A confidentiality notice. Short, one approved wording, applied consistently. It will not create confidentiality on its own, but it tells a misdirected recipient what to do.
- A secure-portal line. "Never email Social Security numbers or bank details; use our secure client portal." Tax preparers are covered by the FTC Safeguards Rule and the IRS expects a written information security plan, so steering clients away from sending sensitive data by email is part of the job. Firms that collect a lot of client bank statements by portal often pair it with a tool for converting PDF bank statements to Excel so the data never has to be retyped.
- The old Circular 230 notice. The "IRS Circular 230 disclosure" was a response to the covered opinion rules, and the IRS removed those rules in 2014. Many firms still carry the paragraph out of habit. Ask your managing partner whether it still serves a purpose before it goes into a new template.
Wording for other countries, if the firm has international clients, is in the guide to email signature disclaimers by country. How AutoSignature applies them by rule is on the email disclaimer software page.
Questions accounting firms ask before buying
What is the best email signature software for accountants?
For a small firm on Microsoft 365 with one template, CodeTwo or Exclaimer Starter are the best value at about $1 per user a month. For a firm with seasonal staff, several offices or a mix of Microsoft 365 and Google Workspace, a flat plan with disclaimer rules by group, such as AutoSignature Business at $239 a month billed yearly, is usually the better fit.
Should a CPA put CPA in their email signature?
Yes, a licensed CPA normally lists the credential after their name, and many firms add the state of licensure. Only people who hold an active license may use it, because state boards of accountancy regulate the title. Central signature software fills the credential from the directory, so only licensed staff get it.
Can I manage email signatures for the whole firm in Microsoft 365 without extra software?
Partly. A mail flow rule can append the same disclaimer to every outgoing message at no extra cost, but the sender does not see it, it lands under the quoted thread in replies, and personalization is limited. Setting each person's visible signature centrally needs a signature management tool.
How much does email signature software cost for a 25-person firm?
At published US list prices, between about $22 and $44 a month for per-seat tools such as Exclaimer and CodeTwo, and $79 to $99 a month for AutoSignature Team, which is a flat plan for up to 25 mailboxes. A Microsoft 365 mail flow rule is free but only covers a disclaimer.
If the flat plan fits your firm, you can build the signature in the console at the top of this page, switch between the partner, the tax director and the staff accountant, and see exactly what each would send.