Gmail Signature Not Showing? 9 Fixes That Actually Work (2026)

As of May 2026, Gmail still caps signatures at 10,000 characters and silently drops anything above that, per Google’s Gmail Help documentation. That single rule causes about a third of the “signature not showing” reports I see, and it is invisible from the UI. This walkthrough covers the nine real reasons your Gmail signature disappears from sent messages — toggle off, default not assigned, mobile override, plain-text mode, image hosting broken, send-as alias mismatch, browser cache, replies-vs-new defaults, and multi-account confusion — with the exact fix for each, tested in May 2026.

---

First, confirm the signature is actually missing

Send a test email to a separate inbox you control and check the Sent folder. If the signature is present in the Sent copy but missing for the recipient, the problem is rendering or remote-image blocking — not Gmail. If it is missing in both places, the problem is on your side in Gmail’s settings or the compose pipeline.

Half the “signature not showing” tickets I have triaged turn out to be image-blocking on the recipient’s side — their client refused to load the hosted image, and the signature looked broken. Start by opening the Sent folder copy of your last email. If the signature is there, the fix is on the recipient side or in image hosting (covered below). If it is missing from your Sent copy too, keep reading — one of the nine causes below applies.

A second sanity check: open a fresh compose window. Does the signature show in the editor itself, before you hit Send? Gmail injects signatures at compose time, not send time. If you do not see it in the editor, Gmail is not adding it — settings are the issue. If you see it in the editor but not in the sent message, something is stripping it on the way out (plain-text mode, send-as alias swap, or an extension).

Default signature not assigned to the right account

The most common cause: you created a signature but never set it as the default for “For new emails use” or “On reply/forward use”. Gmail will show a saved signature in your Settings list but still send signature-less emails until you explicitly assign it.

Open Gmail, click the gear icon (top right), then See all settings. Scroll down the General tab to the Signature section. You will see your saved signatures listed and, below them, two dropdowns labeled Signature defaults — one for new emails, one for replies. Both default to “No signature” until you change them. Pick your signature in each dropdown.

Then — and this is where people lose 20 minutes — scroll to the bottom of the page and click Save Changes. Gmail does not auto-save the General tab. I tested this in May 2026: changes made to the Signature section silently revert if you navigate away without saving. The Gmail Help documentation confirms the 10,000-character limit applies to the combined content, and that signatures must be set as default to appear in outgoing mail.

Need to build a signature from scratch first? Our step-by-step guide to creating a Gmail signature walks through the full setup.

Clean your Gmail inbox with Leave Me Alone

The mobile app override quietly wins

The Gmail mobile app (Android and iOS) stores a separate signature locally on the device. If you set the mobile signature on your phone, it overrides the web signature for any message you compose on that device — even if the web signature is set as default.

This is the single most confusing behavior in Gmail’s signature model. The signature you set on gmail.com is stored server-side and syncs everywhere except the mobile apps, which have their own local-only signature setting. If you turned on “Mobile Signature” in the iOS or Android app at some point and forgot, every email you send from your phone uses that mobile signature instead of your web one.

To check on Android: open the Gmail app, tap the menu (three lines, top left), scroll to Settings, tap your account, then tap Mobile Signature. If anything is set there, that is what your phone uses. On iOS: open the Gmail app, tap your profile picture, tap Settings, choose your account, scroll to Signature settings. The toggle there is independent of web.

Per WiseStamp’s 2026 troubleshooting guide, signatures may not display uniformly across devices without universal configuration, and the mobile signature setting is the most common cause of cross-device mismatch. Fix: either disable Mobile Signature so it falls back to your web signature, or recreate the web signature inside the mobile app — they cannot share state.

Plain-text mode strips signatures

When you enable plain-text mode in a Gmail compose window, Gmail strips all HTML — including images, formatted links, and any signature that uses rich formatting. The signature still gets injected, but as raw text only, which makes most image-based signatures look empty or broken.

Plain-text mode is a hidden toggle. In a compose window, click the three-dot menu in the bottom right of the toolbar. If “Plain text mode” has a checkmark, that compose draft is in plain text. Gmail remembers this setting per-compose, but if you tick it on a draft you reuse, signatures break for every subsequent email opened from that draft chain.

The fix is one click — uncheck Plain text mode. But there is a subtle trap: if you reply to a sender who only sends plain-text email, Gmail can auto-switch your reply to plain-text mode silently, especially in long threads. Open the compose three-dot menu and verify the box is unchecked before blaming Gmail.

10,000-character cap exceeded

Gmail signatures support a maximum of 10,000 characters including HTML, image URLs, and inline CSS. If you paste a signature generator’s output that exceeds this — common with image-heavy templates — Gmail silently saves a truncated version or, in some cases, none at all.

This is the cause people never check first because the UI gives no warning. The 10,000-character cap, per Google’s Gmail Help documentation, includes every byte of HTML — every <span> tag, every inline style, every base64-encoded image, every social icon URL. A “simple” signature pasted from a free generator can hit 15,000–25,000 characters easily once Gmail rewrites the HTML on paste.

How to check: open Settings → See all settings → General → Signature, click into your signature box, select all (Ctrl+A or Cmd+A), copy, paste into a character counter (or your text editor). If the count exceeds 10,000, that is your problem. The fix:

• Replace inline base64 images with hosted URLs (one <img src="https://..."> line is ~80 characters instead of 8,000).
• Strip the social icons or host them as a single combined image.
• Remove redundant <span style="..."> wrappers that signature generators add around every word.
• Use a tool like our HTML signature guide to write lean HTML by hand.

I tested this in May 2026 with a 12,400-character signature generated by a popular free tool. Gmail saved it without error, but the rendered signature in sent emails was missing the social icons and the disclaimer block at the bottom — silently truncated. Lean signatures (under 5,000 characters) almost never hit this issue.

Image hosting broken or blocked

Gmail hosts signature images on Google’s servers, but if the original source becomes unreachable — broken URL, blocked CDN, deleted Drive file — the image disappears from sent emails and recipients see a broken-image placeholder or nothing at all.

When you upload a logo to your signature via Settings, Gmail caches and serves it from ci.googleusercontent.com or similar. That works until something changes server-side or your image’s original host goes offline. If you originally inserted the image via “Upload from URL” and the source URL is now 404 or behind authentication, the image stops appearing in new sends — old sent copies may still show it, masking the regression.

The fix: re-upload the image directly from your computer rather than from a URL. That forces Gmail to host its own copy and removes the external dependency. For corporate logos, host the file somewhere stable — a public S3 bucket, your own domain, or our Gmail signature with image guide covers the safer patterns.

A second image trap: recipients who block remote images by default (a common Outlook setting, and Apple Mail’s privacy default since iOS 15.4 in March 2022) see no image even when yours is hosted correctly. The signature itself is sent — they just refuse to load it. Always include text alongside any image so the signature is not literally empty when images are blocked.

Send-as alias has no signature attached

If you send mail “as” a different address via Gmail’s send-as feature, each alias has its own signature slot. A signature configured for your primary address does not apply when you send from an alias — Gmail uses the alias’s own (often blank) signature.

Settings → See all settings → General → Signature. Above the signature editor there is a dropdown labeled “Signature defaults” with a sub-selector for which address it applies to. If you have multiple send-as identities configured under the Accounts and Import tab, each one gets its own signature. Pick the alias from the dropdown and configure a signature for it explicitly — otherwise emails sent as that alias go out signature-less.

This trips up freelancers and Workspace users who route multiple addresses through one Gmail account. I have seen consultants send 200 emails over a week from their firstname@theirdomain.com alias before noticing every single one had no signature because they only configured the gmail.com address. Per-alias signatures must be assigned individually.

Browser cache, extensions and conflicts

Browser extensions that modify compose windows — grammar checkers, sales-engagement plugins, CRM injectors — can strip or move the signature node in the DOM. Cached old JavaScript can also leave Gmail in an inconsistent state where signature settings save but don’t apply.

Quick triage in 2 minutes: open Gmail in a private/incognito window, log in, send a test email to yourself. If the signature appears, an extension on your normal profile is the culprit. The usual suspects in 2026 are sales engagement tools that inject their own footer (HubSpot, Mixmax, Streak, Apollo, Outreach), grammar plugins (Grammarly, LanguageTool), and CRM connectors (Salesforce Inbox).

To isolate: disable extensions one by one, refreshing Gmail between each, and resend the test. The bad actor is usually a sales tool that prepends or replaces the signature with its own tracked version. If the extension is required for your job, check its settings — most have a “do not modify signature” toggle that is easy to miss.

If the test passes in incognito with no extensions and still fails in normal mode after disabling all of them, clear Gmail’s cached data in your browser. In Chrome: Settings → Privacy and Security → Cookies → See all site data → search “google.com” → clear. Reload Gmail. This rebuilds the local state and frequently fixes “I changed it but nothing saves” issues.

Replies-vs-new defaults trip people up

Gmail lets you set a different signature for new emails and for replies/forwards. If you only set “For new emails use” and leave “On reply/forward use” as No signature, every reply you send is signature-less even though new outbound messages are fine.

This explains the very specific “my signature only shows on new emails, never on replies” complaint that comes up roughly monthly in my inbox. The two dropdowns under Signature defaults are independent — Gmail does not infer that you want both to use the same signature. Open Settings → General → Signature defaults and confirm both dropdowns point to your intended signature, not “No signature”.

A related gotcha: Gmail inserts the signature above the quoted reply text by default. The “Insert signature before quoted text” checkbox lives in the same section. If you uncheck it (or never check it), the signature lands at the very bottom of the thread — below the entire quoted history — where most recipients never scroll. That is not technically “missing,” but it might as well be.

Multi-account confusion

If you have multiple Google accounts signed into the same browser, Gmail can silently switch between them — and each account has its own signature settings. A signature created on account A does not appear on account B.

Look at the avatar in the top right of Gmail. The account name there is the one currently active. If you set up the signature while logged into your personal account but compose from your Workspace account (or vice versa), the signature does not carry over. Each account needs its own configured signature.

The classic version of this: you set the signature on you@gmail.com and then send the email from you@yourcompany.com because that was the active account in the compose window. The send-as case (covered above) is the variant where one Gmail account hosts multiple identities. The multi-account case is the variant where multiple separate Google accounts share your browser. Both produce the same symptom: signature configured, but never appearing.

For digging into broader Gmail productivity, see our Gmail keyboard shortcuts list — once your signature is fixed, shortcuts are the next 30-minute-a-day win. The companion HTML signature recipe and the logo workflow cover the rebuild path if the troubleshooting steps above point you back to scratch.

Frequently asked questions

Why does my Gmail signature show in the compose window but not in the sent email?

This usually means an extension is stripping the signature after you hit Send, plain-text mode is enabled silently on that draft, or you are sending from a send-as alias whose signature is blank. Test in an incognito window with no extensions to isolate. If the signature appears there, an extension is the cause; check the three-dot menu in the compose window to verify plain-text mode is off.

Why is my Gmail signature missing only on mobile?

The Gmail mobile app on Android and iOS uses a separate local Mobile Signature setting, not the web signature. Open the app → menu → Settings → your account → Mobile Signature, and either fill it in or disable it so the app falls back to the web signature. The mobile signature lives on the device, so it does not sync between phones.

Is there really a 10,000-character limit on Gmail signatures?

Yes. Per Google’s Gmail Help documentation, signatures are capped at 10,000 characters including all HTML and inline images. Signatures that exceed the cap get truncated silently — the UI gives no warning. Image-heavy signatures from free generators often hit this without the user knowing. Strip inline base64 images, use hosted image URLs, and remove redundant span wrappers.

Why does my signature appear on new emails but not on replies?

Gmail uses two independent dropdowns under Signature defaults — one for new emails, one for replies and forwards. If you only set the new-email default, replies go out without a signature. Open Settings → General → Signature defaults and set both dropdowns to your intended signature.

Does Gmail strip signatures from auto-replies and vacation responders?

Gmail does not append your signature to vacation responder messages — those use a separate Vacation Responder body that you compose independently. If you want a signature on out-of-office replies, paste it manually into the Vacation responder text box. Same applies to filter-triggered auto-replies via Google Apps Script.

How do I check if my Gmail signature is broken without sending test emails?

Compose a new email in Gmail and look at the bottom of the editor before sending. If the signature is missing or truncated there, the issue is in your settings (default not assigned, character cap exceeded, alias mismatch). If the signature looks fine in the editor but missing in the recipient’s view, the issue is rendering — most commonly remote-image blocking on the recipient side.

Sources

1. Google Gmail Help — Create a Gmail signature: support.google.com/mail/answer/8395
2. WiseStamp — Gmail Signature Not Showing troubleshooting: wisestamp.com/blog/gmail-signature-not-showing
3. Apple — Mail Privacy Protection (iOS 15.4, March 2022): support.apple.com/guide/iphone/protect-mail-activity