Email Signature Logo Size: The Pixel Dimensions and Formats That Work

Add your logo to a signatureDownload the signature image size cheat sheet (PDF)

The numbers, and where they come from

Google publishes the clearest numbers. Its Gmail signature troubleshooting page recommends a signature image 70 to 100 pixels high and 300 to 400 pixels wide, and gives the maximum as 100 pixels high by 1,000 pixels wide. Those are generous upper limits for a wide logo. Most signatures look better smaller.

For reference, the four templates in our free signature generator show a square logo at 110 to 140 pixels wide (48 in the Compact template) and a round photo at 48 to 84 pixels across. Those sizes sit comfortably beside two or three lines of text without dominating the email.

The height matters more than the width. A logo that is too tall pushes your name and number down and makes every short reply look like a newsletter. Keep it at or under 100 pixels high, as Google suggests.

Shape changes the right number. A wide logo, the kind with the name spelled out beside a symbol, can run to 200 pixels wide and still be only 50 high. A square or stacked logo needs less width to read, which is why the templates show square logos at 110 to 140 pixels. If your logo has a lot of fine text in it, consider using just the symbol in the signature, since your business name is already written in text beside it.

Display size is not file size

A picture in an email has two sizes. The display size is how big it appears, set in the signature's code. The file size in pixels is how big the actual image is. They don't have to match, and for sharp results they shouldn't.

Phones and many laptops have high-resolution screens that pack two or three device pixels into each display pixel. A logo file exactly 120 pixels wide, shown at 120 pixels, looks soft on those screens. Export it at roughly double, 240 pixels wide, and let the signature display it at 120. The generator writes the display size into the image's width attribute, which is the method email apps follow most consistently; the Can I email database lists the width attribute as supported in Gmail, Apple Mail and Outlook, with some quirks in Outlook for Windows.

Don't go much beyond double. A huge file still has to download every time someone opens your email, and Google's help page on creating a Gmail signature notes that an image counts towards the signature's 10,000-character limit.

Which file format to use

Use PNG for logos, because it keeps edges and flat colours sharp, and JPG for photographs, because it keeps the file small. The Can I email database lists PNG as supported in Gmail, Outlook and Apple Mail, on computers and phones.

Avoid the two formats that look attractive on the web:

• SVG. The database lists SVG images as unsupported in Outlook for Windows from 2007 to 2016, and notes that Gmail converts them to PNG. A logo that disappears for Outlook users is not worth the sharper edges.
• WebP. WebP images are listed as unsupported in Outlook for Windows from 2007 to 2019, and Gmail converts them to JPG.

One more trap: a dark logo saved on a transparent background can disappear when the reader uses a dark theme. Save logos on a white or light background, with a little padding, so they read on both.

Round photos and corners

The generator's round photo option draws the circle with CSS (the border-radius property). That works in most apps, but Can I email lists border-radius as unsupported in Outlook for Windows from 2003 to 2019, so readers there see a square photo. That is a tidy fallback, not a broken signature.

If the photo must be round everywhere, crop the image file itself into a circle on a white background before uploading it. Outlook then shows the circle because it is part of the picture, not an effect applied to it.

Prepare and add the logo, step by step

1. Decide the display size

For a wide logo, something like 160 to 200 pixels wide and under 100 high. For a square logo or a photo, the template sets it.

2. Export at double size

Any image editor can resize; export at about twice the display size.

3. Choose PNG or JPG

PNG for a logo, JPG for a photo, on a light background.

4. Host it at an https address

Upload it to your website and copy the address of the image file. Paste that address into a private browser window: you should see just the picture.

5. Add it to the signature

Paste the address into the generator's photo or logo box and choose Round (photo) or Square (logo). The generator warns you if the address doesn't start with https.

6. Test in two apps

Copy the signature, install it with the steps for Gmail or Outlook, and send yourself a test. If the picture doesn't appear, our guide to signature images that don't show has the fixes.

When the signature is done, the inbox is the next thing to tidy. Fynl's Starter plan puts your Gmail inbox beside your customers, bookings and invoices, and adds each team member's signature when they write from there. The generator stays free. More free tools are on the free tools page.

Questions people also ask

Sources

• Gmail Help — Troubleshoot issues with Gmail signatures
• Can I email — SVG image format
• Can I email — WebP image format
• Can I email — border-radius