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Design a polished signature with your logo and links, then drop it into Outlook desktop, Outlook on the web or Microsoft 365 — formatting intact.
Outlook is notorious for mangling pasted signatures — swapping fonts, resizing logos and dropping spacing. ProSignature builds signatures with the inline, email-safe HTML Outlook expects, so what you design is what your recipients see.
The same signature works in the new Outlook, classic Outlook desktop, Outlook on the web and Microsoft 365. Need it for your whole company? Deploy branded signatures to everyone with the team plan, or set one up for Gmail too.
Outlook for Windows renders HTML email using Microsoft Word's layout engine rather than a browser engine. That single fact explains almost every Outlook-specific signature failure. Word's engine has no support for modern CSS layout — flexbox and grid simply do not apply — it handles padding and margins inconsistently, it can ignore CSS width on some elements, and it may add small gaps between stacked images that no stylesheet asked for. It also applies its own DPI scaling, which is why a logo that is correct on a Mac can appear oversized on a high-DPI Windows display. None of this is fixable from the outside; it is designed around.
Nested tables remain the only layout method that renders predictably across every Outlook version. Modern CSS layout does not.
Style blocks and external stylesheets are unreliable; attributes on the element itself are not.
Set both as HTML attributes, not only in CSS, so Word's engine has no room to improvise.
Web fonts are ignored; specify a real fallback so text does not land in Times New Roman. See best fonts.
Not embedded files, which can arrive as attachments — sizes are in the image size guide.
Support is patchy; a coloured block that renders beautifully in Gmail may simply not appear.
Because Outlook's behaviour differs so much from every other client, a signature that has only been checked in Gmail has not really been checked. The minimum useful test is to send the signature to yourself and open it in Outlook on Windows, Outlook on the web, and a phone — those three cover the majority of what recipients use. Look specifically for stacked-image gaps, oversized logos, collapsed spacing and fonts that have fallen back. If you are deploying to a team, do this once centrally rather than discovering it through twenty employees: team deployment. The fastest route to a signature that already obeys these rules is a generator that outputs email-safe HTML by default.
Written and maintained by the ProSignature team. Competitor pricing and feature claims on this site are verified against each vendor's live page on the day of writing — last verified 26 July 2026. No affiliate links. How we work.
Step-by-step setup for all four versions of Outlook, including why classic Outlook stores signatures locally so they vanish on a new machine. The HTML rules explain what survives Word's rendering engine, and image sizing covers the DPI scaling that makes logos look oversized on Windows.
Build your signature here, then add it to Outlook in a minute.
Create my signature — freeDesign it in ProSignature, click Copy, then paste it into Outlook's signature editor under Settings. Because the signature uses inline email-safe HTML, the logo and layout stay intact.
Yes. The signature works in the new Outlook, classic desktop Outlook, Outlook on the web and Microsoft 365.
Most signatures break because they use unsupported CSS. ProSignature builds with inline styles that Outlook renders reliably, which is why the paste holds together.