What Belongs in a Professional Email Signature

The fourteen-line monster I inherited

At a previous job I was handed the official company signature: fourteen lines, two banners, six social icons, an inspirational quote, and a request to consider the environment before printing an email nobody was going to print. On a phone it was longer than most of the emails it was attached to. In some replies it rendered as a column of broken image icons and blue question marks.

When I set up signatures for my own site, I went the opposite direction and kept cutting until removing anything else would delete useful information. What survived was four lines. This post is what made the cut, what absolutely did not, and the technical traps that make email signatures far more annoying than they have any right to be.

The four lines that earn their place

A signature exists to answer two questions: who is this person, and how do I reach them. Everything beyond that is decoration competing for attention with the actual message above it.

My template: full name on line one. Role and company on line two. One phone number on line three, and only if I genuinely answer it. Website or booking link on line four. That is the whole thing. First emails to a stranger get all four lines; ongoing threads honestly only need the first. I built mine in the email signature generator once, and I have not touched the HTML since, which is exactly how often anyone should be hand-editing signature HTML.

What to leave out

Each extra element costs more attention than it returns. The test I apply: would a recipient ever act on this? Nobody has ever followed a company on three social networks from an email footer.

• The inspirational quote. It ages badly and reads differently in a complaint thread
• Six social icons. Pick one profile that is actually maintained, or none
• A scanned handwriting image. It adds nothing and triggers image blocking
• vCard attachments on every email, which make some filters twitchy
• The second phone number that rings a desk nobody sits at
• Legal-sounding confidentiality disclaimers that no court asked for, in tiny gray text, adding four lines of noise

Images: where signatures break

Almost every mangled signature I have debugged came down to images. Several email clients block remote images by default, so a signature that is one big image renders as an empty box with a filename in it. The recipient sees nothing, screen readers see nothing, and the text inside the image cannot be copied or searched. Never ship the one-big-image signature.

If a logo genuinely belongs there, the rules are short. Host it at an absolute public URL, because embedded and locally referenced images break the moment the email leaves your machine. Keep it small, around 100 pixels wide displayed, and export at double size so it stays sharp on high-density screens, with the display width set explicitly in the HTML. Set alt text so the blocked state still says your company name. And compress the file: my logo went from 180KB to 12KB through the image compressor with no visible change, which matters when it rides along on every single email you send.

What must UK companies legally include?

This part is not style advice. Under the Companies Act 2006, a UK limited company must state its registered name, company registration number, place of registration, and registered office address on its business emails, the same disclosures required on letterhead. Sole traders are exempt, but if you trade as a limited company in the UK, those details belong in the signature block of external email.

The pattern I use for UK clients: keep the human signature to the four lines, then add one compact line of small print underneath, something like the company name, registered in England and Wales, company number, registered office. One line, small text, done. In the US there is no general equivalent requirement for ordinary businesses, though regulated industries carry their own disclosure rules, and marketing emails everywhere have separate laws about unsubscribe links that a signature does not satisfy.

Why is everyone still using table HTML in 2026?

Because Outlook. Desktop Outlook still renders email with a Word-based engine, and modern CSS layout simply does not survive it. Floats drift, margins vanish, and a signature built with divs and flexbox arrives in Outlook looking like it fell down the stairs. Old-fashioned HTML tables with explicit widths render predictably in effectively every client, which is why every serious signature is secretly a tiny table.

My other rendering rules, learned the slow way: design to about 320 pixels wide so nothing wraps strangely on phones, where a large share of email gets read. Keep text at 12 to 14 pixels in system fonts like Arial or Helvetica, because custom fonts silently fall back anyway. Then send test emails to a Gmail account, an Outlook account, and an iPhone before rolling anything out. Every signature disaster I have seen shipped after being tested in exactly one client, the sender's own.

Links, tracking, and small quality-of-life details

Signature links are a slow but steady traffic channel, and untracked clicks from mail clients show up in analytics as direct traffic, which tells you nothing. I tag my website link with UTM parameters, source signature and medium email, using the same conventions from my UTM naming guide. Over a year, it is genuinely interesting to see how many visits a polite footer link produces.

Two smaller details. Keep the visible link short and human-readable: a signature pointing at a clean URL slug looks deliberate, while a two-line query string looks like a phishing attempt, and the slug generator tidies up page names before they end up in front of clients. And if your work involves in-person meetings, one small QR code linking to a booking page pulls its weight on email that gets read on desktop: I make those with the QR code generator, pointing at the tagged link, so even the scans get measured. In Gmail itself, signatures are plain to set up per account, and Gmail supports different signatures per send-from address, which the help page above walks through.