"DPI" (dots per inch) comes up constantly in government exam photo requirements, and just as often gets misunderstood. This guide shows you how to actually check an image's DPI using only your browser or built-in device tools — no software installation required — and clarifies what the number does and doesn't tell you.

What DPI actually is

DPI describes how many pixel "dots" would be printed per inch if the image were printed at a specific physical size. It is a print-resolution concept, not a property of the image file's content by itself — a 1000×1000 pixel image can be "300 DPI" at one physical print size and "72 DPI" at another, because DPI is really just pixels ÷ inches. Critically, DPI has no fixed relationship to file size in kilobytes; changing an image's stated DPI value does not add or remove pixels or compress the file.

Method 1: Check via your browser's developer tools

Open the image in a new browser tab (drag the image file into an open browser window, or right-click a web image and choose "Open image in new tab").
Right-click on the image and choose "Inspect" or "Inspect Element" to open developer tools.
Look at the image's natural pixel dimensions, often shown in the console or by hovering over the image element — this gives you pixel width and height, from which DPI can be calculated if you know (or decide) the intended print size.

This method gives you pixel dimensions reliably, but browsers generally don't display an embedded DPI metadata value directly this way — for that, use the next method.

Method 2: Your operating system's built-in file properties

Windows: Right-click the image file → Properties → Details tab. Look for "Horizontal resolution" and "Vertical resolution" — these are the file's embedded DPI values.
macOS: Open the image in Preview → Tools → Show Inspector (or Cmd+I), then check the size/resolution panel.
Android/iPhone: Built-in gallery apps typically don't expose DPI directly; use a file manager app's "details" or "properties" view if available, or check via a browser upload as described below.

Method 3: Upload to any browser-based image tool and check its reported stats

Many browser-based image tools — including our own photo resizer — display the pixel dimensions of your uploaded image immediately after upload, without installing anything. While our tool reports pixel dimensions rather than an embedded DPI metadata tag specifically, pixel dimensions are usually what you actually need for a government form's requirement, since most forms specify pixel size directly rather than asking you to check embedded DPI metadata.

The common misconception this guide exists to correct

Changing an image's DPI metadata value does not change its pixel dimensions or its file size in kilobytes. If your government exam form is rejecting your photo for being too large in KB, changing the DPI setting in an editor will almost never fix that — you need to actually resize and/or compress the image. See our photo resizing guide for the correct approach.

When DPI actually matters

DPI genuinely matters in a narrower set of situations than most people assume:

Printing a physical photo — for example, taking a photo to a photo studio to get a physical passport-size print for an in-person biometric verification step. Here, DPI (combined with the physical size you want) determines how many pixels the printed photo needs to look sharp.
Some scanning software settings — when you scan a document yourself, your scanner software often asks you to choose a DPI setting, which does affect how many pixels the resulting scan has (higher DPI settings produce more pixels and larger files) — this is a genuine, separate DPI-related decision at scan time, distinct from later editing an already-scanned file's DPI metadata.

For nearly everything else in a government exam application — uploading a digital photo or signature to a web form — what actually matters is pixel dimensions and file size in KB, not the DPI metadata tag.