How many pixels is 3.5 × 4.5 cm?

It depends on the DPI. The same 3.5 × 4.5 cm becomes 276 × 354 pixels when the DPI is 200, 413 × 531 when it is 300, and 827 × 1063 when it is 600. Enter the cm values and the DPI here and the tool does the conversion for you.

My notice says 6 cm × 2 cm for the signature. What DPI should I use?

The Staff Selection Commission notices give no DPI for the signature, only the cm size and 10 KB to 20 KB. 200 DPI gives 472 × 157 pixels, which leaves plenty of room under 20 KB for black ink on white paper. Check the weight on the result card and compress afterwards if needed.

I typed 3.5 × 4.5 cm at 300 DPI. Why did I get 398 × 531 pixels instead of 413 × 531?

“Lock aspect ratio” was ticked, so an upright 3:4 phone photo was fitted inside the box without cropping and kept its own shape, which leaves it about 3.4 cm wide. Untick it, make sure “Crop to fill” is chosen, and run it again; the edges are trimmed evenly to give exactly the size you typed.

Does the file really carry the cm size?

It carries the pixels and the DPI, and together those define the cm size. JPG and PNG results have the DPI written in, so photo software and printers show the intended centimetres. A WebP result keeps the pixel size but has no DPI field.

Can I resize in cm and to a KB limit in one go?

Not on this page: it sets the dimensions, not the weight. Resize here first, look at the file size on the result, and if it is over the limit open the compressor for that KB value. Compressing a small cm-sized picture rarely needs to shrink it further.

Resize Image in CM: Centimetres to Pixels at Any DPI

A notice that says “3.5 cm × 4.5 cm” is describing paper, not a screen. A digital photo has no centimetres of its own, only a grid of pixels, so a size in cm stays undefined until a DPI is attached to it. The same 3.5 × 4.5 cm is 276 × 354 pixels at 200 DPI and 413 × 531 pixels at 300 DPI. Pick the wrong DPI and the picture is either too small to pass a pixel check or far heavier than the KB limit beside it.

Here the unit is already centimetres, the boxes start at 6.0 × 2.0 (the signature strip in Staff Selection Commission notices), the DPI at 300 and “Crop to fill” is on. Change the DPI to the figure your instructions give, overwrite the width and height with your own cm values, and the tool converts them to pixels, resizes the picture and records that DPI inside the JPG or PNG, so a printer or a portal that reads it sees the intended physical size.

Before and after

A wooden ruler with centimetre markings standing in a black pot beside a silver pencil and other stationery — The dashed frame on the left marks the part that fits the new shape. It was scaled to exactly 709 × 236 px, and the top and bottom outside the frame were trimmed.
The file went from 1.26 MB to 34.7 KB.
The image on the right is the actual file the tool above produced.

The same photo resized to 709 × 236 pixels — The dashed frame on the left marks the part that fits the new shape. It was scaled to exactly 709 × 236 px, and the top and bottom outside the frame were trimmed.
The file went from 1.26 MB to 34.7 KB.
The image on the right is the actual file the tool above produced.

How to use it

Open the photo, signature scan or document you need at a set size in centimetres.
Set the DPI first. Use the value in your notice (200 is common on Indian application forms); if none is given, 300 suits printing.
Keep 6.0 × 2.0 or type your own width and height in cm, such as 3.5 × 4.5 for a photo. Leave “Crop to fill” on for an exact frame; ticking “Lock aspect ratio” instead fits the picture inside the box, so one side comes out shorter.
Resize, then read the pixel size on the result card. If the form also caps the weight in KB, pass the file through the matching compressor.

From centimetres to pixels: the arithmetic

One inch is 2.54 cm, and DPI counts how many pixels fill one inch. So pixels = centimetres ÷ 2.54 × DPI, rounded to the nearest whole pixel. At 200 DPI a centimetre is about 78.7 pixels; at 300 DPI it is about 118.1. Some sizes that turn up on application forms:

3.5 × 4.5 cm photo: 276 × 354 px at 200 DPI, 413 × 531 px at 300 DPI. 6.0 × 2.0 cm signature strip: 472 × 157 px at 200 DPI, 709 × 236 px at 300 DPI. 4.0 × 2.0 cm signature: 315 × 157 px at 200 DPI. 3.5 × 6.0 cm photo-and-signature sheet: 276 × 472 px at 200 DPI. Secondary sites sometimes quote 275 × 354 for the first one; the one-pixel gap is only rounding and no portal is likely to care.

Enlarging a small picture to reach these numbers works, but it adds no detail. Start from the sharpest original you have, ideally a scan or a full-size phone photo, rather than a screenshot of an earlier upload.

Form sizes given in cm

Staff Selection Commission notices for CGL, CHSL, MTS, Constable (GD), Stenographer and Junior Engineer ask for the scanned signature at about 6.0 cm (width) × 2.0 cm (height), JPEG/JPG, 10 KB to 20 KB. No DPI is stated; one annexure in the same notices says about 4.0 cm wide instead, so read your own notice before choosing between the two. The guidelines on the NIC exam portal (pariksha.nic.in) want the photo and signature together as one image of 3.5 cm by 6.0 cm at 200 DPI, up to 50 KB, and a UPPSC advertisement (A-5/E-1/2018) used the same 3.5 cm by 6.0 cm combined image with a 50 KB cap.

A notice that gives cm but no DPI is in practice asking for a rough on-screen size: 200 DPI keeps the file light, while 300 gives a crisper print at the cost of more KB. Whichever you use, the shape is what matters most, so crop to the exact proportion rather than letting the picture stretch.

Frequently asked questions

How many pixels is 3.5 × 4.5 cm?: It depends on the DPI. The same 3.5 × 4.5 cm becomes 276 × 354 pixels when the DPI is 200, 413 × 531 when it is 300, and 827 × 1063 when it is 600. Enter the cm values and the DPI here and the tool does the conversion for you.
My notice says 6 cm × 2 cm for the signature. What DPI should I use?: The Staff Selection Commission notices give no DPI for the signature, only the cm size and 10 KB to 20 KB. 200 DPI gives 472 × 157 pixels, which leaves plenty of room under 20 KB for black ink on white paper. Check the weight on the result card and compress afterwards if needed.
I typed 3.5 × 4.5 cm at 300 DPI. Why did I get 398 × 531 pixels instead of 413 × 531?: “Lock aspect ratio” was ticked, so an upright 3:4 phone photo was fitted inside the box without cropping and kept its own shape, which leaves it about 3.4 cm wide. Untick it, make sure “Crop to fill” is chosen, and run it again; the edges are trimmed evenly to give exactly the size you typed.
Does the file really carry the cm size?: It carries the pixels and the DPI, and together those define the cm size. JPG and PNG results have the DPI written in, so photo software and printers show the intended centimetres. A WebP result keeps the pixel size but has no DPI field.
Can I resize in cm and to a KB limit in one go?: Not on this page: it sets the dimensions, not the weight. Resize here first, look at the file size on the result, and if it is over the limit open the compressor for that KB value. Compressing a small cm-sized picture rarely needs to shrink it further.