How to Use a Resolution Converter for DPI, Aspect Ratio, and Pixel Dimensions

Choose the calculation that matches your inputs

Resolution Converter helps you move between familiar display measurements when you know some, but not all, of the numbers. You can use pixel width and height to check an aspect ratio and pixel totals, use a diagonal size with pixel dimensions to calculate DPI, or estimate a 16:9 resolution from diagonal size and DPI.

Choose the mode that matches the information you have. Aspect-ratio mode is useful for checking whether a screen or image matches a target shape. DPI mode connects pixel dimensions with diagonal size. Resolution-from-DPI mode works in the other direction, estimating pixel dimensions from physical size and DPI.

How to use Resolution Converter

Open Resolution Converter and select one of the supported modes: aspect-ratio, DPI, or resolution-from-DPI.
Enter the measurements required by that mode. For aspect-ratio mode, provide a positive pixel width and height. The optional fields start with width 1920, height 1080, diagonal size 0, and DPI 0, so review the values before calculating. For DPI mode, provide positive width, height, and diagonal size. For resolution-from-DPI mode, provide a positive diagonal size and DPI.
Run the calculation and review the returned measurements. In aspect-ratio mode, the result includes a reduced integer aspect ratio, a decimal ratio rounded to 10 decimal places, total pixel count, and megapixels rounded to 2 decimal places.
If you selected DPI mode, check the DPI value, dot pitch in millimeters, and total pixel count. DPI and dot pitch are rounded to 2 and 4 decimal places respectively.
If you selected resolution-from-DPI mode, read the estimated width, height, total pixel count, and megapixels. This calculation interprets the display as 16:9 and rounds width, height, and total pixel count to whole numbers, with megapixels rounded to 2 decimal places.

If the result is unsuccessful, check the mode and its required inputs. Aspect-ratio and DPI modes need positive pixel dimensions; DPI mode also needs a positive diagonal size. Resolution-from-DPI mode needs both a positive diagonal size and positive DPI. An unrecognized mode also returns an unsuccessful result.

How to read the result

Read the output according to the question you started with. A reduced integer ratio gives the simplified relationship between width and height, while the decimal ratio gives a more precise comparison. Total pixel count describes the number of pixels represented by the entered dimensions, and megapixels express that count in a larger unit.

DPI connects pixel dimensions to diagonal size, and dot pitch reports the spacing in millimeters. In resolution-from-DPI mode, the estimated dimensions are not a general aspect-ratio conversion: they are calculated under a 16:9 interpretation. Treat an unsuccessful result as a sign that the selected calculation lacks a valid required input rather than as a usable measurement.

Worked example

A designer checks whether a 1920 by 1080 canvas has the intended widescreen shape.

Enter 1920 for width and 1080 for height, select aspect-ratio mode, and calculate.

The result gives a reduced integer ratio of 16:9, a decimal ratio of 1.7777777778, a total pixel count of 2,073,600, and 2.07 megapixels.

Limitations

Resolution estimates use a 16:9 aspect-ratio interpretation rather than a user-supplied aspect ratio.
Calculations are unsuccessful when mode-specific required dimensions, diagonal size, or DPI are not positive.

Common errors

A zero or negative required value causes an unsuccessful result. Replace it with a positive pixel dimension, diagonal size, or DPI according to the selected mode, then calculate again.

FAQ

Which mode should I use to calculate an aspect ratio?

Use aspect-ratio mode when you have positive pixel width and height and want the reduced ratio, decimal ratio, pixel count, and megapixels.

What inputs are required for a DPI calculation?

Provide positive pixel width, height, and diagonal size in DPI mode. The result includes DPI, dot pitch in millimeters, and total pixel count.

Can the tool estimate resolution from screen size and DPI?

Resolution-from-DPI mode uses a 16:9 interpretation, so enter a positive diagonal size and positive DPI to receive estimated width, height, pixel count, and megapixels.