Image DPI Converter
Work the pixels, DPI and print-size triangle for any image.
What this tool does
An image DPI converter works the three-way relationship between pixels, DPI and print size: print size = pixels ÷ DPI. A 2,400-pixel-wide image at 300 DPI prints 8 inches wide; the same image at 72 DPI would print 33 inches but look soft. DPI is a printing density, not a property of the file - the pixels are fixed, and DPI only decides how large they land on paper. The converter works any direction: size from pixels, or pixels from a target size.
Works the full image triangle: pixels, DPI and print size, any one from the other two.
Returns the print size in both inches and centimetres for the entered resolution.
Flags the resolution thresholds that separate screen, office print and press quality.
Converts a full pixel dimension like 2400x3000 in one pass, not one number at a time.
How to use it
- Enter the image's pixel dimensions, width and height.
- Enter the DPI you intend to print at, or the print size you want.
- Read the third value: print size at that DPI, or the pixels needed.
- Check the quality verdict for the DPI entered.
Why use this calculator
Working the pixels, DPI and print-size triangle removes the most common print failure: an image that looks fine on screen and comes out of the lab blurry. The pixel count is fixed the moment the photo is taken; only the DPI decides how large those pixels spread across the paper. Below about 150 DPI the individual dots become visible, and below 100 the image looks soft - a fact that print labs encode as minimum size limits.
Why we built it
We built the image DPI converter to return both inches and centimetres and to state the quality verdict, because the number alone does not tell you whether the print will look right. The pixels to inches converter does the plain unit conversion without the print framing, the resize image to exact size resamples an image to a target pixel dimension, and the millimetres to inches converter handles the physical units.
For layout work that mixes print and screen units, the CSS unit converter translates px, rem, em and pt, and the area converter works the print dimensions into an area.
Who this tool is for
- Photographers checking what size an image will print
- Designers preparing files for press or photo labs
- Anyone who has received a blurry print they did not expect
- Print shop staff quoting sizes from customer files
When to use it
- Before ordering a print larger than screen size.
- Setting the DPI in an export dialog.
- Checking whether a client's file can produce a poster.
- Working out the pixel dimensions a layout needs.
How it is calculated
Print width (inches) = pixel width ÷ DPI. Print height follows the same rule. Going backwards, pixel width = target inches × DPI. Centimetres multiply inches by 2.54. Effective DPI is the actual density when an image is placed at a given size, which is the figure that decides quality.
Worked example: a 2,400 × 3,000 pixel portrait at 300 DPI prints 8 × 10 inches. At 150 DPI the same pixels cover 16 × 20 inches - more size, less density. To fill a 20 × 25 cm print requires 2,362 × 2,953 pixels at 300 DPI.
Upscaling cannot add detail. Resampling a 1,000-pixel image to 3,000 does not make a 3,000-pixel image - the printer still receives the original detail, spread thinner. Only the camera or scanner creates real pixels.
Quality thresholds
| DPI | Typical use | Verdict |
|---|---|---|
| 72 | Web and screen | Never for print |
| 100 – 150 | Large format, viewed from distance | Acceptable for posters |
| 200 – 240 | Everyday photo prints | Good |
| 300 | Photo lab and inkjet standard | Excellent |
| 600+ | Line art, text-heavy print | Press quality for fine detail |
A worked example
These are the values the calculator opens with, so you can see exactly what it does with them. Change any value on the page and the result updates; the figures below come from the same calculation.
| Input | Value |
|---|---|
| Pixel dimensions | 2400 × 3000 |
| DPI | 300 |
With those inputs, the calculator returns:
- Print size: 8 × 10 inches
- Print size: 20.3 × 25.4 cm
- At 150 DPI: 16 × 20 inches
- Quality verdict at 300 DPI: excellent
What you enter, and what you get back
| Item | Details |
|---|---|
| Pixel dimensions | Width and height of the image. |
| DPI or target size | Set the density, or the size you want to fill. |
| Result | Print size in inches and cm, effective DPI and quality verdict. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| Print softer than expected | Effective DPI below 150. | Reduce the print size or accept the softness. |
| Print smaller than intended | DPI metadata higher than expected. | Check the file's embedded DPI, not the pixel count. |
| Resized file still looks blurry | Upscaling cannot create detail. | Re-capture at higher resolution for the target size. |
| Lab rejects the file | Below the lab's minimum DPI. | Order a smaller size or reduce the DPI requirement. |
Assumptions and limitations
- Assumes the image is printed at the stated DPI without cropping.
- DPI metadata in a file can be misleading; the pixel count is the hard limit.
- Upscaling does not add real detail - the verdict applies to the pixels as captured.
- Viewing distance and output technology affect perceived quality beyond the numbers.
Frequently asked questions
How do I find the print size of an image?
Divide the pixel dimensions by the DPI. A 2,400 × 3,000 pixel image at 300 DPI prints 8 × 10 inches. The pixel count is fixed; DPI decides how large those pixels spread. This calculator returns the size in inches and centimetres.
What is the difference between DPI and PPI?
DPI (dots per inch) counts the ink dots a printer lays down; PPI (pixels per inch) counts the image's pixels. For sizing calculations they are used interchangeably, but strictly the printer controls DPI while the file carries PPI. Screen work is PPI; the print lab converts between them.
How do I change the DPI of an image?
Changing DPI does not resample the pixels - it only changes how large they print. In an editor, use the image size dialog with resampling off to change DPI alone, or on to actually add or remove pixels. Changing DPI with resampling off leaves the image data untouched.
What DPI should my image be for print?
300 DPI is the standard for photo prints and inkjet output, giving excellent results at normal viewing distance. For large posters viewed from a metre or more, 150 DPI is usually fine. Below 100 DPI prints look visibly soft.
How many pixels is an 8x10 at 300 DPI?
2,400 × 3,000 pixels. Multiply each dimension of the print by the DPI: 8 × 300 = 2,400 and 10 × 300 = 3,000. For centimetres, multiply by 2.54 first: 20 × 25 cm at 300 DPI needs about 2,362 × 2,953 pixels.
Does DPI affect image quality on screen?
No - on screen only the pixel count matters, and DPI is ignored entirely. A 300 DPI file and a 72 DPI file with identical pixels look identical on screen. DPI only becomes meaningful when the image is printed at a physical size.