How do I add a signature in Gmail?

Go to Gmail Settings (gear icon) > See all settings > General tab. Scroll to the Signature section and click 'Create new'. Add your content, set it as the default under 'Signature defaults', then click Save Changes at the bottom of the page.

Does Gmail have a signature character limit?

Yes. Gmail enforces a 10,000-character hard limit on signatures, counting the total HTML including all tags. If your signature exceeds this, Gmail silently truncates it at 10,000 characters without warning.

Why is my Gmail signature not showing?

Check Gmail Settings > General > Signature. Confirm a signature is created and assigned under 'Signature defaults' for 'For new emails use'. Also verify you haven't accidentally disabled it in the compose window.

Gmail Signature: How to Create, Add & Customize

Q: Can I use CSS in a Gmail signature?

Gmail strips all blocks. All CSS must be written as inline styles on each HTML element. Supported inline properties include: color, background-color, font-size, font-weight, font-family, margin, padding, border, text-align, text-decoration, and line-height. Flexbox, CSS grid, and position are not supported.

Gmail enforces two hard constraints on signatures: a 10,000-character limit (total HTML) and no <style> blocks — all CSS must be inline. It also separates desktop and mobile signature storage completely. This guide covers setup across all surfaces and the technical rules that determine what renders correctly.

Create a Gmail-Compatible Signature

SignForge outputs inline CSS with no style blocks — the only format Gmail renders reliably. Free, no signup.

Create My Signature →

Works with Gmail, Outlook, Apple Mail & more

Gmail Signature Technical Constraints

10,000-character hard limit

Gmail counts every character in your signature HTML, including all tags and attributes. If your signature HTML exceeds 10,000 characters, Gmail silently truncates it at the 10,000-character mark — no error, no warning. Keep signatures compact. SignForge-generated signatures are typically 1,500–3,000 characters.

<style> blocks are stripped entirely

Gmail removes any <style> element from your signature before sending. All CSS must be written as inline style attributes on each individual HTML element: <p style="color:#333;font-size:14px;">, not via classes or stylesheet rules.

Supported inline CSS properties

Gmail renders: color, background-color, font-size, font-weight, font-family, margin, padding, border, border-radius, text-align, text-decoration, line-height, width, max-width. Not supported: display:flex, display:grid, float, position, CSS variables, calc().

Image handling

Images must be hosted at a public URL (https). Gmail does not support base64-encoded images in signatures. When pasting a signature, Gmail may re-host your images on its own CDN (lh3.googleusercontent.com) — this is normal and images will still display correctly.

Desktop and mobile are separate

Gmail desktop (web) and Gmail mobile app store signatures completely independently. A signature set in Gmail.com settings does NOT appear as the mobile signature, and vice versa. For rich HTML, set up on desktop. The mobile app only supports plain text.

How to Add a Signature in Gmail (Desktop)

Open Gmail Settings

Click the gear icon (top right), then See all settings.

Go to the General Tab

You land on General by default. Scroll down to the Signature section.

Create a New Signature

Click Create new, give it a name (your name or “Work”), then click Create.

Paste Your Signature

Click inside the signature editor box. Press Ctrl+V (or Cmd+V on Mac) to paste. Gmail preserves the HTML structure including inline styles, images, and links.

Set as Default

Under Signature defaults, assign your signature for “For new emails use” and “On reply/forward use” separately.

Save Changes

Scroll to the bottom and click Save Changes. Open a new compose window to verify.

How to Add a Gmail Signature on Mobile

Mobile signatures are stored separately from desktop and support plain text only. For a rich HTML signature, configure it on desktop — it will not appear as the mobile signature, but emails sent from desktop with the HTML signature are delivered with full formatting intact.

Open Gmail App Settings

Tap the hamburger menu (top left), scroll down, tap Settings.

Select Your Account

Tap the account you want to configure.

Tap Mobile Signature

Scroll to Mobile Signature and tap it.

Enter and Save

Type your plain-text signature (name, title, company, phone is sufficient for mobile). Tap OK.

Google Workspace: Admin-Controlled Signatures

If you use Gmail through a Google Workspace (formerly G Suite) account, your administrator may have configured one or more of the following:

Organization-wide footer

Workspace admins can enable an appended footer that is added to all outgoing emails server-side. This appears after your personal signature. You cannot see or edit it from Gmail settings — contact your IT admin if it duplicates information in your personal signature.

Locked signature

Admins can lock signatures so users cannot modify them. If your Gmail signature settings are greyed out or read-only, your organization has enabled signature enforcement.

Signature delegation

If you manage a shared inbox or send on behalf of another account, that account's signature settings apply — not your own. Switch to the delegated account's settings to configure its signature.

How to Use Multiple Gmail Signatures

Gmail supports multiple named signatures. Useful if you have a formal signature for new emails and a shorter version for replies, or if you have multiple professional roles.

•Create each signature via Settings → General → Signature → Create new.
•When composing, click the pen icon (Insert signature) at the bottom of the compose window to switch between signatures.
•Set a shorter signature (name and phone only) as the reply default under Signature defaults to reduce clutter in long threads.

Troubleshooting Gmail Signature Problems

Signature not appearing in new emails

Check Settings > General > Signature > Signature defaults. Confirm your signature is selected for 'For new emails use'. If it shows '(No signature)', click the dropdown and select your signature, then Save Changes.

Signature shows extra blank lines or spacing

This happens when Gmail adds its own paragraph wrapper around pasted content. Use SignForge's HTML copy function and paste into the Gmail signature editor. Avoid pasting from a word processor — the extra paragraph tags cause the blank lines.

Signature appears cut off / truncated

Your signature HTML has exceeded Gmail's 10,000-character limit. Gmail truncates silently. Simplify your design — reduce the number of elements, shorten link URLs, or remove less-important fields.

Images not showing to recipients

Images must be hosted at public HTTPS URLs. If you use a corporate email proxy or VPN, images from internal URLs won't load for external recipients. Use a CDN or image host (Cloudinary, your website) for logo images.

Signature appears on replies when it shouldn't

Go to Settings > General > Signature > Signature defaults. Change the 'On reply/forward use' dropdown to '(No signature)' or a minimal text-only version.

Frequently Asked Questions

Does Gmail support HTML email signatures?

Yes, with constraints. Gmail strips <style> blocks but preserves inline CSS. It supports table-based layouts, inline styles for color/font/margin/padding, hosted images, and hyperlinks. It does not support CSS flexbox, grid, float, or position.

How do I add a logo to my Gmail signature?

Host your logo at a public HTTPS URL (your website, a CDN, or a cloud storage service set to public). In SignForge, paste the URL in the Photo URL field. Gmail will preserve the <img> tag with the URL when you paste the signature.

Can I use the same signature in Gmail and Outlook?

Yes. SignForge generates HTML using table layout and inline CSS, which is compatible with both Gmail and Outlook. Create once, paste into both.

How do I remove my Gmail signature?

Go to Settings > General > Signature. Click the trash icon next to a signature to delete it permanently, or set the 'Signature defaults' dropdowns to '(No signature)' to stop auto-insertion without deleting.

Related Guides

Create Your Gmail Signature Now

6 professional templates. Custom colors. Social links. No signup required — free forever.

Create My Signature →

Works with Gmail, Outlook, Apple Mail & more