Aadhaar Signature Size & Format Requirements (2026)

Last verified against UIDAI portal guidelines: May 2026. Requirements can change — always confirm on myaadhaar.uidai.gov.in before submitting.

What UIDAI actually requires

UIDAI does not publish a single universal signature specification that applies to every service. Different portals — the Aadhaar self-service update portal, state government forms, bank KYC forms linked to Aadhaar — each set their own upload constraints. That said, the requirements across all of them cluster around the same numbers, and if you hit these targets you'll pass on virtually every portal:

• File format: JPEG (JPG). Some portals accept PNG; none reject JPEG. When in doubt, use JPEG.
• File size: under 50 KB. Aim for 15–30 KB to be well inside any limit. A clean JPEG at medium quality from a phone photo is typically 10–25 KB after background removal.
• Dimensions: roughly 200×60 px to 300×100 px — wider than tall, with the signature centred in the frame. The exact pixel count varies by portal; these are safe targets that scale down cleanly from any larger export.
• Background: white. Not transparent. Transparent PNGs often render as solid black on government upload forms, which will immediately fail the automated check.
• Ink colour: black or dark blue. The signature must be clearly visible against the white background.

The specific portal you're submitting to will show its own constraints on the upload screen — look for the “file size limit” and “accepted formats” fields before uploading. Those override anything you read here.

Why most submissions get rejected

The UIDAI portal rejection error messages are not helpful. “Invalid file format” or “file size exceeded” is all you get, with no hint about what specifically went wrong. Based on the most common issues:

• File too large. Phone cameras produce JPEGs in the 2–5 MB range by default. A raw photo of your signature is 40–100x larger than the portal will accept. You need to crop and compress it, or process it through a tool that produces a small output. The export from this tool is typically under 30 KB.
• Wrong format. Submitting a PNG when the portal expects JPEG, or a PDF when it expects an image, will fail silently on some portals. Use JPEG unless the portal explicitly lists PNG as accepted.
• Non-white background. If you photographed your signature on lined paper, cream stationery, or forgot to remove the paper background, the system sees a coloured or textured background instead of white. This fails the image validation check on many government portals.
• Signature too faint.Pencil or light-blue ink doesn't give enough contrast against white paper. The image looks blank or nearly blank when compressed to the required file size. Use black or dark navy pen.
• Angled or blurry photo. Photographing your signature at an angle introduces keystone distortion. Blurry photos lose the fine detail of thin strokes. Hold your phone directly above the paper, braced on a table.

How to create a compliant signature image

The fastest reliable workflow uses the Upload tab in the tool above. Here's the full sequence — it takes about three minutes the first time.

1. Sign on plain white printer paper. A4 or US Letter, blank, no lines, no watermark. Use a black ballpoint or felt-tip pen. Sign roughly in the centre of the page, leaving white space all around — at least 30% margin. Bigger margins give the background removal algorithm more reference data.
2. Photograph it straight-on. Hold your phone directly above the paper, lens parallel to the page. Even lighting — daylight from a window, no flash. If you can see a shadow on the page in the camera preview, move the paper or change your position.
3. Upload the photo to this tool. In the Upload tab, select your photo. The tool applies adaptive threshold to remove the paper background automatically. Check the preview — the background should be gone, with only your ink strokes remaining on a transparent checkerboard.
4. Adjust if needed. If paper is still visible, slide the threshold higher. If your strokes are getting thin, slide it lower. For photos with shadows or uneven lighting, try the AI background removal option — it handles trickier photos better than the threshold slider.
5. Export as white-background PNG or JPEG. For Aadhaar and most government portals, use Download White-bg PNG or Download JPG — not the transparent PNG. The white background is what portals expect. JPEG produces a smaller file, which helps with the size limit.
6. Check the file size before uploading.Right-click the downloaded file → Properties (Windows) or Get Info (Mac). If the size is under 50 KB, you're ready. If it's over, the JPEG option is smaller than PNG — try that instead.

Scanning vs. photographing

If you have access to a flatbed scanner, use it. Scans at 200 DPI on plain white paper produce cleaner, more even results than phone photos because the lighting is controlled and there's no camera angle. Export the scan as JPEG at 100 DPI (re-sampling down from 200) to get the file size under the limit without losing legibility.

Most people don't have a scanner. A modern smartphone camera held directly above the page, in good daylight, produces results that are good enough for government portal uploads. The key is the lighting and the angle, not the megapixel count.

Aadhaar e-Sign and other digital signature services

Aadhaar-based e-Sign (through UIDAI's e-Sign gateway) is a different thing from a signature image. e-Sign is a certified electronic signature service that uses OTP authentication and creates a legally binding digital signature with an audit trail. Banks, government portals, and NBFCs use it for loan agreements and other high-value documents.

For e-Sign, you don't upload a signature image — the system uses your Aadhaar number and an OTP to authenticate you, and generates the signature certificate automatically. That's handled entirely by the e-Sign gateway, not by this tool.

What this tool covers: creating a clean image of your physical handwritten signature for use on forms, applications, and documents that ask you to upload or embed a signature image. That's a different use case from certified e-Sign.

Troubleshooting a rejected upload

If the portal rejects your image without a clear error, try these in order:

1. Switch from PNG to JPEG (or vice versa, depending on what you tried first).
2. Check file size. Anything over 50 KB is likely to fail. Export JPEG at lower quality to reduce size.
3. Retake the photo on plain white paper. Lined or coloured paper is the single most common cause of invisible failures.
4. Make sure the background is white, not transparent. Download white-background JPEG, not transparent PNG.
5. Try a different browser. Some older government portal implementations have quirks with certain browsers' file upload handlers.

If none of the above works, the portal may have specific pixel dimension requirements not publicly documented. In that case, contact the portal's helpdesk — they can usually tell you the exact spec for that service.