How to Resize a Signature Image for Email, Word & PDF Documents

The correct signature image sizes

Different use cases need different dimensions:

Email signature: 300×100 px — the standard for Gmail, Outlook, Apple Mail. Wide enough to look professional, small enough not to dominate the footer.

Word / Google Docs document: 200×80 px — inline signatures in contracts and letters. Smaller than email, fits comfortably in a signature block.

Stamp-style (round seal): 150×150 px — square format for circular stamp signatures or logos used as signatures.

High-resolution print: 500×200 px — for legal documents, agreements, or formal correspondence where the signature is printed and viewed up close.

These are guidelines, not rules — adjust based on your specific template and branding.

How to resize your signature image free

PDFSpot's Resize Signature tool resizes your signature to any standard size while keeping the background transparent (PNG) so it blends naturally into any email or document.

1. 1Upload your signature image (JPG, PNG, or WebP).
2. 2Choose a preset: Email (300×100), Document (200×80), Stamp (150×150), Large (500×200), or enter custom dimensions.
3. 3Choose a transparent or white background.
4. 4Select PNG (for transparency) or JPG output.
5. 5Download your resized signature.

Transparent vs white background — which to use?

Transparent background (PNG) — the signature blends naturally over any background colour. Essential for email signatures, where recipients may use dark mode or a coloured email theme. Also best for Word documents with coloured headers.

White background (JPG) — some platforms don't support transparent images. Older versions of Word, some PDF viewers, and certain email clients may show a coloured box around a transparent PNG. If that's happening, switch to white background.

Rule of thumb: use transparent PNG by default. Only switch to white JPG if you see a coloured box appearing where it shouldn't.

How to add a signature image to Gmail

1. In Gmail, click the Settings gear → See all settings. 2. Go to the General tab, scroll to Signature. 3. Click Create new signature. 4. In the signature editor, click the Image icon (picture icon in the toolbar). 5. Upload your resized signature PNG. 6. Set it to the size "Small" in Gmail's size options. 7. Click Save Changes at the bottom.

For best results, upload a 300×100 px PNG with a transparent background.

How to add a signature image to Outlook

1. In Outlook, go to File → Options → Mail → Signatures. 2. Click New to create a signature. 3. In the editor, click the Image icon. 4. Browse to your signature PNG file. 5. Right-click the inserted image → Picture → Size tab — confirm the dimensions are correct. 6. Click OK and set this signature as your default for new messages.

Outlook sometimes shows a white box around transparent PNGs depending on the version and recipient's email client. If this happens, use a white-background JPG instead.

How to insert a signature image into Word or Google Docs

In Microsoft Word: 1. Place the cursor where you want the signature. 2. Go to Insert → Pictures → This Device. 3. Select your signature PNG. 4. Right-click → Wrap Text → In Front of Text (for flexible positioning) or In Line with Text (for fixed position in a signature block). 5. Drag the corners to adjust size if needed.

In Google Docs: 1. Go to Insert → Image → Upload from computer. 2. Select your signature PNG. 3. Click the image, then drag the corner handles to resize.

Getting a good signature image to start with

For the best result, start with a high-resolution scan of your signature:

1. Sign your name on white paper with a dark pen. 2. Scan at 300 DPI or higher, or photograph under good lighting. 3. Crop tightly around the signature. 4. If possible, use an image editor to remove the white background (make it transparent) before resizing. 5. Upload the transparent PNG to the resizer.

If you don't have a scanner, signing on a phone screen and screenshotting also works — just make sure there's good contrast between the signature and background.