How many pixels is a 4x6 photo?
A 4x6 photo (4 × 6 cm) at 300 DPI is 472 × 709 pixels. At 400 DPI it is 630 × 945 pixels, and at 600 DPI it is 945 × 1417 pixels. Likewise, a 3x4 photo (3 × 4 cm) at 300 DPI is 354 × 472 pixels. The pixel count depends on resolution (DPI — dots per inch), so the same print size maps to several pixel sizes.
Conversion formula: pixels = (cm ÷ 2.54) × DPI. Example for the width of a 4x6: 4 ÷ 2.54 × 300 ≈ 472 pixels.
Note for readers used to inches: in Vietnam, "4x6" refers to 4 × 6 centimeters (about 1.57 × 2.36 in) — not the 4 × 6 inch print size used in the US.
cm-to-pixel conversion table for ID photo sizes
| Photo size | Dimensions (cm) | 300 DPI | 400 DPI | 600 DPI |
|---|---|---|---|---|
| 2x3 | 2 × 3 cm | 236 × 354 px | 315 × 472 px | 472 × 709 px |
| 3x4 | 3 × 4 cm | 354 × 472 px | 472 × 630 px | 709 × 945 px |
| 3.5x4.5 | 3.5 × 4.5 cm | 413 × 531 px | 551 × 709 px | 827 × 1063 px |
| 4x6 | 4 × 6 cm | 472 × 709 px | 630 × 945 px | 945 × 1417 px |
| 5x5 (US visa) | 5 × 5 cm (2 × 2 in) | 591 × 591 px | 787 × 787 px | 1181 × 1181 px |
Which DPI Should You Use?
300 DPI is the minimum for sharp prints and for acceptance by Vietnam's online application portals. If your source photo is sharp enough, 400–600 DPI gives crisper prints. Upscaling a low-pixel photo does not make it sharper — sharpness comes from the original shot.
Which size is used for which document?
| Size | Used for |
|---|---|
| 4x6 | Vietnamese passport (mandatory), online submissions on the National Public Service Portal, some visa applications |
| 3x4 | Driver license, school records, job applications, CVs, student cards |
| 3.5x4.5 | Schengen visa, UK visa, several European countries |
| 5x5 | US visa (DS-160), US green card |
Vietnamese passport photos submitted online carry extra face and background rules — see the dedicated guide on passport photo size and pixels.
Public Service Portal requirements for the 4x6 photo
Per the official photo guidance for passport applications on Vietnam's Public Service Portal, an online portrait must have:
- Aspect ratio: width × height = 4 × 6
- Resolution: at least 300 DPI (i.e., 472 × 709 pixels or larger)
- Background: white, no shadows
- Face: about 75% of the frame, looking straight, both ears visible, no glasses
- Format: JPEG 2000 (see our JPEG 2000 guide)
- Recency: taken within the last 6 months
Common Pitfall
A photo with the right pixel count can still be rejected for a wrong face ratio or a non-compliant background (the portal's "background gray level not suitable" error). Pixel size is only one of several criteria — see how to fix the gray-background error.
Get the right pixel size without doing the math
You don't need to crop to exact pixels yourself. All it takes is a portrait shot from your phone:
- Open the 4x6 photo editor or the 3x4 photo tool;
- Upload your portrait;
- AI auto-crops to the exact ratio, replaces the background with compliant white, and exports at 300+ DPI;
- Download the file for online submission or printing.
Create a Correctly Sized Photo Now
AI frames your photo to exact 4x6 or 3x4 pixel dimensions with a portal-compliant white background — free preview.
Start NowNote
This article reflects the Public Service Portal photo guidance and standard technical conversion formulas as of July 2026. Requirements may vary by procedure — verify the latest guidance at dichvucong.gov.vn before applying.