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Resize a photo to 51×51 mm (602×602 pixels)
A 51×51 mm print at 300 DPI is 602×602 pixels. Set 51×51 mm and 300 DPI in the panel and choose crop to fill: a 4:3 phone photo loses 25% and still gives 1,506 pixels per inch. As a JPEG, a head-and-shoulders portrait comes to about 60.8 KB at the panel's default quality 85 and 45.7 KB at quality 75.
51×51 mm at 300 DPI (602×602 px)
JPG · no file-size limit · 51x51 mm at 300 DPI · white background
No file-size limit is set: PixelFit saves at high quality and changes only the format and any pixel size you set. 51x51 mm at 300 DPI is 602x602 pixels.
Fit, background and padding crop to fill · white background
Saving presets is part of Pro.
The result appears here: the exact byte count, pixel size and quality, the size before and after, a preview and a download button.
The batch kit (one ZIP for up to 500 photos, several photos merged into one PDF) is part of Pro.
51×51 mm at a glance
| Physical size | 51×51 mm = 2.01×2.01 in |
|---|---|
| Pixels at 300 DPI | 602×602 px (362,404 pixels, 0.36 MP) |
| Shape | 1:1, square (width ÷ height = 1) |
| From a 12 MP phone photo | 1,506 pixels per inch after the crop to fill (25% cut) |
| Copies per sheet | 2 on 4×6 in · 20 on A4 · 20 on US Letter |
| At 600 DPI | 1205×1205 px (1.45 MP) |
| Resampling passes from a phone photo | 3024×3024 crop → 1512×1512 → 756×756 → 602×602 |
| Estimated JPEG (portrait photo, quality 75, 300 DPI) | 45.7 KB |
| JPEG without a KB limit (panel default, quality 85) | 60.8 KB |
How 51×51 mm turns into pixels
An inch is exactly 25.4 mm, so at 300 DPI the pixel size is 51 mm ÷ 25.4 × 300 = 602.362, rounded to 602 px wide, and 51 mm ÷ 25.4 × 300 = 602.362, rounded to 602 px tall. 51×51 mm is square, 2.01×2.01 in in the other unit.
The same 51×51 mm needs 402×402 px at 200 DPI and 1205×1205 px (1.45 MP) at 600 DPI. PixelFit writes the DPI you set into the JPEG header (the JFIF density field), so print software that reads it knows the file is meant to come out at 51×51 mm.
Is your photo sharp enough for 51×51 mm?
After the crop to fill, this is how many source pixels land on each inch of 51×51 mm. Above 300 DPI the picture is reduced to 300 DPI; below it, PixelFit has to enlarge the crop and fine detail softens.
| Starting image | Crop to fill keeps | Area lost | Pixels per inch at 51×51 mm | To reach 300 DPI |
|---|---|---|---|---|
| 12 MP phone photo (4032×3024, 4:3) | 3024×3024 (left and right cut) | 25% | 1,506 DPI | reduced (0.2×) |
| 24 MP camera photo (6000×4000, 3:2) | 4000×4000 (left and right cut) | 33.3% | 1,992 DPI | reduced (0.15×) |
| Full HD screenshot (1920×1080, 16:9) | 1080×1080 (left and right cut) | 43.8% | 538 DPI | reduced (0.56×) |
| Vertical phone video frame (1080×1920, 9:16) | 1080×1080 (top and bottom cut) | 43.8% | 538 DPI | reduced (0.56×) |
51×51 mm in pixels at each print resolution
Pixels = millimetres ÷ 25.4 × DPI. The panel uses 300 DPI unless you change it; the file sizes are for a portrait saved as JPEG.
| Resolution | Pixels | Megapixels | JPEG q75 | JPEG q90 |
|---|---|---|---|---|
| 150 DPI | 301×301 | 0.0906 MP | ≈ 16.4 KB | ≈ 26.2 KB |
| 200 DPI | 402×402 | 0.16 MP | ≈ 25 KB | ≈ 40.4 KB |
| 300 DPI | 602×602 | 0.36 MP | ≈ 45.7 KB | ≈ 75.7 KB |
| 400 DPI | 803×803 | 0.64 MP | ≈ 70.9 KB | ≈ 121 KB |
| 600 DPI | 1205×1205 | 1.45 MP | ≈ 135 KB | ≈ 244 KB |
Will a 51×51 mm photo fit a KB limit?
Saved at 300 DPI (602×602 px), a head-and-shoulders portrait of 51×51 mm comes to about 35.3 KB at JPEG quality 60, 45.7 KB at 75 and 75.7 KB at 90, and about 26.6 KB as WebP at 75. Dropping to 200 DPI (402×402 px) brings quality 75 down to about 25 KB, but the print then holds fewer pixels per inch.
At 300 DPI the photo does not fit under 20 KB even at quality 30; it fits under 50 KB up to quality 77 and under 100 KB up to quality 93; under 200 KB it fits even at quality 95. Set the KB limit next to the size and PixelFit picks the highest quality that fits.
Printing 51×51 mm copies
Without margins or cutting gaps, 2 copies fit on one 4×6 in (102×152 mm) photo print, 20 on an A4 sheet, 20 on US Letter (some turned sideways where that packs more). Print at 100% scale, never "fit to page", or a small ID photo of 51×51 mm comes out the wrong size; 602×602 px at 300 DPI is exact.
Other 1:1 print and photo sizes
These sizes have the same 1:1 shape as 51×51 mm, so a photo cropped for one fits the others with no further crop.
| Size | Pixels | Scale from 51×51 mm |
|---|---|---|
| 2×2 inch photo | 600×600 | 1× |
| 45×45 mm photo | 531×531 | 0.88× |
| 35×35 mm photo | 413×413 | 0.69× |
| 8×8 inch print | 2400×2400 | 3.99× |
| 12×12 inch print | 3600×3600 | 5.98× |
| 600×600 square | 600×600 | 1× |
| 700×700 square | 700×700 | 1.16× |
| 512×512 PWA icon | 512×512 | 0.85× |
Forms in the PixelFit directory that ask for 51×51 mm
Matched by the photo size stated in each form's official notice (checked October 2026); open the form's page for its KB limit, background and other rules.
- Maharashtra B.P.Ed CET 2025 online application (MAH B.P.Ed CET)
- US nonimmigrant visa (Form DS-160) digital photo (US visa)
- US Diversity Visa (DV) Program entry photo (DV lottery)
How to resize a picture to 51×51 mm
-
Add the picture
Drop, paste or pick the photo in the PixelFit panel at the top of this page; it is decoded in your browser and never uploaded.
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Set the size
Pick mm as the unit, enter 51×51 mm and 300 DPI; the tool turns that into 602×602 pixels.
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Choose how it fits
Choose crop to fill to keep the 1:1 frame without stretching (a phone photo loses 25%, left and right cut). Fit inside keeps the whole picture as a 602×452 file instead; Pad with colour puts that on a full 602×602 canvas.
-
Pick the format and download
Keep JPG (without a KB limit PixelFit saves at quality 85, about 60.8 KB for a head-and-shoulders portrait) so the 300 DPI stamp travels with the file, or choose PDF to get the picture as a PDF page, then download.
Sources
- State CET Cell Maharashtra: B.P.Ed-CET 2025 Information Brochure, State Common Entrance Test Cell, Maharashtra, checked 31 October 2026: cetcell.mahacet.org/wp-content/uploads/2023/12/B.P.Ed-CET…
- U.S. Department of State: Digital Image Requirements for visa photos (travel.state.gov page as served on adoption.state.gov), U.S. Department of State, Bureau of Consular Affairs, checked 31 October 2026: adoption.state.gov/content/travel/en/us-visas/visa-inform…
- Inch (1 inch is exactly 25.4 mm), Wikipedia, checked 31 October 2026: en.wikipedia.org/wiki/Inch
- Measured by PixelFit with sharp 0.35.5 / libvips 8.18.7 on 31 October 2026, from the sample photo President Barack Obama.jpg by Pete Souza (Official White House photo) (Public domain): commons.wikimedia.org/wiki/File:President_Barack_Obama.jpg
Frequently asked questions
How do I resize a photo to 51×51 mm?
Open the photo in the PixelFit panel on this page, set 51×51 mm at 300 DPI (602 × 602 px), choose crop to fill and download. From a 12 MP phone photo that crops 25% (left and right cut) and still leaves 1,506 pixels per inch to work with.
How many pixels is 51×51 mm?
51×51 mm is 602×602 px at 300 DPI, 1205×1205 px at 600 DPI and 301×301 px at 150 DPI (pixels = mm ÷ 25.4 × DPI).
What DPI should a 51×51 mm photo have?
PixelFit uses 300 DPI, which makes 51×51 mm exactly 602×602 px; print it at 100% scale. At 150 DPI the same 602×602 pixels would print 4.01×4.01 in, twice as large and with half the density.
How many 51×51 mm photos fit on one sheet?
Without margins, 20 fit on A4 (210×297 mm), 20 on US Letter and 2 on a 4×6 in photo print, turning them sideways where that packs more. Leave a few millimetres for cutting.
How big is a 51×51 mm JPEG at 300 DPI?
For a head-and-shoulders portrait about 45.7 KB at quality 75 (35.3 KB at 60, 75.7 KB at 90, 60.8 KB at the panel's default quality 85); a detailed outdoor photo is about 91.6 KB at quality 75, estimated from measured encodes of real sample photos at 602×602 px.
Related
Same 1:1 ratio
Nearby sizes
- 600×750 px digital passport photo 4:5
- 500×700 portrait 5:7
- 40×50 mm photo 472:591 (about 4:5)