Inspect resolution honestly
- Choose a JPG, PNG, or WebP image.
- Compare embedded resolution metadata with the exact pixel dimensions.
- Use the 300/240/150 PPI print-size calculations to plan output.
Image DPI and Resolution Checker
Inspect embedded JPG or PNG resolution metadata and calculate real print sizes from exact pixel dimensions without uploading the photo.
DPI metadata is often misunderstood. A 3000 × 2000 photo does not become sharper because its tag says 300 DPI instead of 72 DPI; its printable resolution depends on how many pixels are spread across the chosen physical size.
How OpenFileTools processes it
Local processing, explicit choices.
OpenFileTools reads only bounded image headers for common resolution tags, decodes dimensions locally, and calculates physical print sizes without changing the source.
Quick technical summary
What this tool changes.
| Property | Behavior |
|---|---|
| Processing | Browser local; image bytes are not uploaded to OpenFileTools |
| Always measured | Exact pixel width and height |
| Metadata | Common JPEG JFIF/EXIF and PNG pHYs density evidence when present |
| Planning sizes | Physical size calculations at 300, 240, and 150 PPI |
Separate pixel dimensions from DPI metadata
Image DPI Checker reports the image's exact pixel dimensions first, then reads common JPEG JFIF/EXIF or PNG pHYs density metadata where available. A 3000 × 2000 image contains the same pixel detail whether its metadata says 72 DPI or 300 DPI; changing the tag alone does not create new detail.
- Missing DPI metadata is not the same thing as low resolution.
- Pixel dimensions determine how many samples are available for a chosen print size.
- Density metadata can influence default physical-size interpretation in some applications.
Calculate effective print size at useful PPI targets
For print planning, the tool converts the actual pixel dimensions into physical sizes at 300, 240, and 150 pixels per inch. Those calculations show how large the existing pixels can be spread at each sampling density without pretending that one PPI target fits every printer, substrate, viewing distance, or workflow.
- 300 PPI is a common high-detail planning reference, not a universal legal requirement.
- Large-format output can be acceptable at lower effective PPI depending on viewing distance and process.
- A destination specification should override generic planning targets.
Use metadata and effective PPI for different questions
Use embedded density metadata when you need to understand how a file declares its intended physical size. Use effective PPI when you need to decide whether the available pixels are sufficient for a specific print width and height. If the destination requires a particular metadata tag, use a dedicated DPI-writing tool after confirming that the pixel dimensions are already adequate.
Questions, answered.
Is a 72 DPI image automatically low quality?
No. Pixel dimensions matter first. Effective PPI depends on the physical size at which those pixels are printed.
Does changing 72 DPI to 300 DPI improve detail?
Not by itself. Rewriting density metadata without adding real source detail does not create sharper pixels.
Why does my image have no DPI value?
Some encoders omit density metadata. The checker still reports the exact pixel dimensions and calculated print sizes.
What PPI should I print at?
Use the printer or destination specification when one exists. The 300/240/150 PPI sizes are planning references, not universal acceptance rules.
Related guide
Read the related guide