Resize Image to Any Size in Pixels, cm, mm or Inches
Set the exact size your form, print shop or app asks for — in pixels, centimetres, millimetres, inches or as a percentage — and resize up to 20 photos in one go. Pictures are cropped or padded instead of stretched, and the DPI is saved in the file.
Need a KB limit as well as a size? Use Resize Image to KB, which sets exact pixels and a file-size target together.
Pixels, centimetres and DPI: how they connect
A screen or an upload form only counts pixels. Centimetres and inches matter only when the picture is printed, and the link between them is the resolution, measured in DPI (dots per inch). A 3.5 × 4.5 cm passport photo needs 413 × 531 pixels at 300 DPI, but only 207 × 266 pixels at 150 DPI.
KbSnap does that sum for you. Pick cm, mm or inches, choose a DPI, and the tool shows the exact pixel size it will produce before you press Resize. The DPI is also written into the JPG or PNG file, so print shops and editors read the right physical size.
Choosing between crop, border and stretch
When the new size has a different shape from your photo, something has to give. Crop to fit fills the whole size and trims the edges evenly, which is best for portraits where the face stays in the middle. Add border keeps the entire picture and fills the gap with the colour you choose, which suits documents and logos where nothing may be cut off. Stretch squeezes the picture to fill the size and can make faces look wider or thinner, so use it only for graphics where distortion does not matter.
Making a photo smaller without losing sharpness
Shrinking an image in one big jump can leave jagged edges. KbSnap reduces large pictures in steps of one half and finishes with a smooth final pass, which keeps text and edges clean. Making a photo larger cannot add detail that was never captured, so enlargements look softer. If you need a bigger print, start from the original camera file rather than a copy that was already shrunk.
Resizing many photos at once
Add up to 20 images, set the size once and press Resize. With Keep proportions switched on, every photo gets the width you typed and its own matching height, which is right for a batch of different-shaped pictures. Switch it off to give every photo exactly the same width and height. Download the results one by one or as a single ZIP. Everything is processed on your device, so private pictures are never uploaded.
When you also need a file size limit
Dimensions and file size are separate limits. A form can ask for 200 × 230 pixels and also a maximum of 50KB. This tool sets the dimensions. For a KB limit, open Resize Image to KB, which lets you crop to the exact pixels and reach a size target at the same time.
Common print sizes in pixels
| Size | At 150 DPI | At 300 DPI |
|---|---|---|
| Passport photo 3.5 × 4.5 cm | 207 × 266 | 413 × 531 |
| Stamp size 2 × 2.5 cm | 118 × 148 | 236 × 295 |
| US visa photo 2 × 2 in | 300 × 300 | 600 × 600 |
| A4 page 21 × 29.7 cm | 1240 × 1754 | 2480 × 3508 |
Pixel sizes are rounded to the nearest whole pixel.
How to use it
- Choose one or more images (JPG, PNG, WebP or iPhone HEIC).
- Pick a unit — pixels, cm, mm, inches or % — and type the width and height.
- Leave Keep proportions on, or switch it off and choose crop, border or stretch.
- Press Resize, then download each image or all of them as a ZIP.
Tips for accurate sizes
- For web forms and apps, type pixels. DPI makes no difference on screen.
- For prints, choose 300 DPI. 150 DPI is enough for large posters viewed from a distance.
- Check the Output line under the size boxes before you resize; it shows the exact pixels you will get.
- Use Crop to fit for portraits and Add border for documents, so nothing important is lost or distorted.
Frequently asked questions
How do I resize an image to a size in cm?
Choose cm as the unit, type the width and height, and pick a DPI. KbSnap converts the size to pixels at that DPI and shows the result before you resize.
What DPI should I choose?
For screens and online forms DPI does not matter, only pixels do. For photo prints use 300 DPI. The chosen value is saved in the JPG or PNG file.
Will resizing stretch my photo?
Not unless you pick Stretch. With Keep proportions on, height follows width. With it off, Crop to fit trims the edges and Add border fills the gap.
Can I make a small photo bigger?
You can, but no tool can add detail that was never captured, so the enlarged picture looks softer. Use the original file when you can.
How is this different from Resize Image to KB?
This tool changes dimensions. Resize Image to KB changes dimensions and also reduces the file to a KB limit, which is what many exam and job forms ask for.
Can I resize several images at once?
Yes, up to 20 images, each up to 20MB, downloaded individually or as a ZIP.
Does it work with iPhone HEIC photos?
Yes. HEIC photos are converted when you add them, and the result is saved as JPG unless you choose another format.
Are my images uploaded?
No. Images are processed by your browser on your device and never sent to KbSnap or anyone else.
Related tools
Exact pixels and a file-size limit together.
Image Compressor →Compress up to 20 images to a KB limit.
Passport Size Photo Maker →35×45mm photos and printable A4 sheets.
Photo Size Checker →Check a photo before you upload it.
Helpful guides
- KB vs Pixels vs DPI: What Photo Upload Forms Check — Does 200 DPI change the KB? How many pixels is 3.5×4.5 cm? Which number does the portal check? KB, pixels and DPI explained with worked examples.
- Reduce Photo Size in KB on Your Phone (Android & iPhone) — A step-by-step way to shrink a phone photo to 20KB, 50KB or 100KB for an online form without making it blurry — and why the obvious shortcuts fail.