Email signature size: the dimensions that work
The right size depends on where the signature is read: a wide monitor in Outlook, a phone in Gmail, a high-resolution laptop screen. These are the dimensions we use in our templates, and why.
Quick reference
| Element | Displayed at | Upload the file at | Format |
|---|---|---|---|
| Whole signature | under 450–600 px wide | n/a | HTML text and tables |
| Logo | 100–150 px wide, up to ~80 px tall | 2× (e.g. 240 px wide) | PNG (transparency) or JPG |
| Headshot | 60–90 px square | 160–200 px square | JPG |
| Social icons | 20–24 px square | 2× (e.g. 40–48 px) | PNG |
| Each image file | tens of kilobytes, not megabytes | ||
Logo size
A signature logo is a recognition cue, not a banner. Between 100 and 150 pixels wide is enough to read a wordmark; beyond that it starts competing with your name. Height matters as much as width: a tall logo pushes your contact details down. Wide, short logos (a mark next to the name) work best.
Google's help page on signature images in Gmail recommends an image 70–100 pixels high by 300–400 pixels wide, and gives a maximum of 100 pixels high by 1,000 pixels wide. That guidance is for images you add with Gmail's own editor; a signature pasted from Fairsig already sets the display width in its HTML.
CEO with company logo
 | Priya Raman Chief Executive Officer Meridian Analytics | |
| ||
| Made with Fairsig | ||
This logo file is 240 × 80 px and is displayed at 110 px wide in the Corporate template: sharp on retina screens, about 10 KB.
Photo size
Headshots work at 60 to 90 pixels square: big enough to recognise a face, small enough to sit next to three lines of text. Crop to head and shoulders before uploading. A full-body photo at that size is just a figure. See email signatures with a photo for more on choosing and hosting it.
Sales manager with photo
 | Jordan Ellis Regional Sales Manager Bluegate Logistics |
| Made with Fairsig | |
The photo is a 160 × 160 px file displayed at 80 × 80 px in the Classic template. Rounded corners appear in most apps; classic Outlook for Windows shows it square.
Image size by template
Every Fairsig template sets the display size of its images in the HTML (in pixels):
| Template | Photo | Logo |
|---|---|---|
| Classic | 80 × 80 | 100 wide |
| Modern | 64 × 64 | 90 wide (100 under a photo) |
| Bold | 72 × 72 | 110 wide |
| Centered | 72 × 72 | 120 wide |
| Corporate | 72 × 72 | 110 wide |
| Compact, Minimal | none | none |
Logos keep their proportions: the height follows from the width you upload.
Retina screens: upload at twice the size
Most phones and many laptops have high-density screens with two or three device pixels per CSS pixel. An image that is exactly 100 px wide, shown at 100 px, looks soft on them. Upload the file at twice the display size and let the HTML set the display width: the image stays sharp, and the file is still small. Fairsig's own social icons are 40 px files shown at 20 px for this reason.
File size
Your signature images download with every email you send and every reply in the thread. A 2 MB photo straight from a camera is wasteful and slow on mobile data. Resize before uploading: a 200 × 200 JPG headshot is typically 10–30 KB, and a simple PNG logo often less. Save photos as JPG and logos with flat colors or transparency as PNG. SVG is not a safe choice, because Gmail doesn't display SVG images.
How mail apps scale images
- Always set a width. Without a width in the HTML, some versions of Outlook for Windows display an image at its file's pixel size, so a 600 px logo shows at 600 px. Fairsig sets
widthon every image. - Phones shrink wide content. Mobile apps scale down or wrap content that is wider than the screen. Keeping the signature narrow avoids sideways scrolling and tiny text.
- Linked images may be blocked. Many mail apps don't load remote images until the reader allows it. Set the size anyway, so the layout doesn't jump when images appear, and keep all contact details in text.
- Embedded images become attachments. Images pasted into a signature editor are sometimes sent as attachments or inline files. Linking them by
https://URL avoids that, and in Gmail it keeps the signature under the 10,000-character limit.
Character size: Gmail's 10,000-character limit
“Size” also means length. Gmail accepts up to 10,000 characters in a signature, counting the HTML code, and an image you add with Gmail's editor counts toward that limit. The example signatures on this site produce between about 900 and 2,600 characters; the generator shows a live counter for yours. See the Gmail guide if you hit the limit.
Questions
What is the best size for an email signature logo?
Display it 100–150 px wide and no more than about 60–80 px tall, and upload the file at twice that size (for example 240 px wide) so it is sharp on high-resolution screens. Gmail's own guidance for signature images is 70–100 px high by 300–400 px wide, with a maximum of 100 px high.
What size should my signature photo be?
Show it at 60–90 px square. Upload a square image of 160–200 px, cropped to your head and shoulders, so it stays sharp on retina screens and small in kilobytes.
How wide should an email signature be?
Keep the whole signature under about 600 px wide, the classic width of email layouts, and ideally under 450 px so it fits a phone screen without scrolling sideways.
Ready? The free Fairsig generator builds a signature that works in Gmail, Outlook and Apple Mail, in your browser, with no sign-up. Create your signature →