Free local photo tool · no upload
Resize Image in CM Online
This photo resizer in cm prepares images for form uploads and printing at a specified physical size. Enter the requested width and height in cm, or switch to millimeters, and the live conversion shows exactly how many output pixels the selected DPI requires.
Resize in CM
Set your image size
Your image stays on your device.
Output preview
Preview scaled to your screen, not actual print size.
Formats, quality and print sizes
JPG and PNG include the selected DPI. Whole pixels are rounded, so the reported physical size can differ slightly. PDF uses the exact requested page size. Screen previews are not a physical ruler.
Up to 80 MB per source, 40 megapixels and 10,000 pixels per side for source and output. These are working limits; some devices may need smaller images. SVG, PSD and camera RAW are not supported. HEIC/HEIF and TIFF decode locally; some variants may be unreadable. TIFF uses only the first page; animations use a static first frame.
JPG is lossy and turns transparency white. PNG keeps transparency in Crop or Stretch; Keep whole image flattens all transparency to white and adds margins when shapes differ. Resizing and a higher DPI cannot create missing detail. Presets describe measurements. Check the current form or authority requirements.
How do I resize a photo to exact cm?
Choose the width and height in centimeters, select a DPI, and convert each physical measurement to pixels with px = cm ÷ 2.54 × DPI. LensUp rounds to the nearest whole pixel, then resamples the photo locally in your browser.
| Physical size | Nearest pixel size |
|---|---|
| 3.5 × 4.5 cm | 413 × 531 px |
| 6 × 2 cm | 709 × 236 px |
| 2 × 2 cm | 236 × 236 px |
An online photo resize width and height in cm task has two independent choices: physical pixel dimensions and framing. LensUp keeps those choices visible. It never silently stretches a face, signature or document to a different aspect ratio.
How to resize a photo in centimeters
- Choose one local imagePick a JPG, PNG or other browser-readable image. Processing stays on your device; there is no sign-up, upload or watermark.
- Set centimeters, millimeters and DPIUse a measured preset or enter custom dimensions. The image resize in cm calculation updates immediately with the nearest whole-pixel result.
- Choose how to fit, then exportKeep whole image is the default and adds white margins when needed. Lock original proportions to adjust one side, or choose Crop to fill and move the frame. Inspect the preview, then download JPG, PNG or an exact-size PDF.
Resize image in cm and kb as two separate constraints
A physical size and a file-size ceiling measure different things. The centimeter setting determines output pixels at the chosen DPI. The optional KB ceiling searches JPEG quality while preserving those pixel dimensions, and reports the actual final file size.
A low ceiling can require lower JPEG quality. If it cannot be reached while preserving the required pixels, LensUp keeps the dimensions and says the limit was not met. Keep required text, facial edges and signature strokes readable, and compare the result with the source.
Photo resize in cm presets and printing limits
The measured presets include 3.5 x 4.5 cm for a common passport-style form, 6cm x 2cm for an SSC-style signature field, and 2 x 2 cm. These are convenient dimensions, not acceptance rules for every authority. Always follow the current form and leave a safe content margin.
DPI is a conversion scale, not a promise of print-lab colour or extra detail. A 3.5 centimeter source enlarged to many pixels may look soft if the original was small. LensUp sets the requested pixel grid and writes the selected DPI into the JPG or PNG file; it cannot recreate detail that the camera never captured.
Frequently asked questions
How many pixels is 3.5 x 4.5 cm at 300 DPI?
Using the nearest-pixel rule, 3.5 cm becomes 413 px and 4.5 cm becomes 531 px at 300 DPI. The live converter recalculates both values when you choose another DPI.
How do I resize image in cm 6cm x 2cm for a signature?
Choose the 6 × 2 cm preset and confirm the DPI requested by the current form. Keep whole image fits the complete signature with white margins; use Crop to fill only when the outer areas can be removed safely.
How do I print at the requested centimeter size?
Download the exact-size PDF and print at Actual size or 100%, with Fit to page disabled. The PDF page uses the requested dimensions; select paper large enough for the image and printer margins. JPG and PNG include DPI metadata but some print apps override it. No physical printer calibration is performed.
Should I crop or stretch when the aspect ratios differ?
Crop to fill preserves proportions but removes outer image areas; move the crop box to keep important content. Keep whole image adds white margins without cropping. Stretch keeps every pixel but changes proportions, so use it only when that distortion is acceptable.