Quick answer
Megapixels = width × height ÷ 10⁶, and print size = pixels ÷ dpi. A 6000 × 4000 image is 24 MP and prints at 300 dpi at 20 × 13.33 inches.
Enter the width, height and print resolution. The calculator returns the megapixels and the print size.
Related tools: Resolution Scale Calculator: Scaled resolution at a percentage. 16:9 Aspect Ratio Calculator: The missing dimension for a 16:9 frame. Screen Size Calculator: Width, height and area of a screen from its diagonal and aspect ratio.
How to use the Image Resolution Calculator
- Enter width (px) (above 0).
- Enter height (px) (above 0).
- Enter print resolution (dpi) (above 0). It starts at 300.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Width | A number, in px | > 0 |
| Height | A number, in px | > 0 |
| Print resolution | A number, in dpi | > 0, starts at 300 |
Formula and method
Formula
megapixels = width × height ÷ 10⁶; print size = pixels ÷ dpi
IEEE-754 double precision; shown to the decimals indicated.
300 dpi is a common target for photo prints.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Width = 6000; Height = 4000; Print resolution = 300.
| Result | Value |
|---|---|
| Resolution | 24 MP |
| Print size | 20 × 13.33 in |
Example 2
Inputs: Width = 4032; Height = 3024; Print resolution = 72.
| Result | Value |
|---|---|
| Resolution | 12.19 MP |
| Print size | 56 × 42 in |
Example 3
Inputs: Width = 1920; Height = 1080; Print resolution = 96.
| Result | Value |
|---|---|
| Resolution | 2.07 MP |
| Print size | 20 × 11.25 in |
The first line is the headline result (resolution). Below it the image Resolution Calculator lists print size, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Worked example
6000 ÷ 300 = 20 in and 4000 ÷ 300 = 13.33 in. At 150 dpi the same image prints at 40 × 26.7 in with less sharpness.
Viewing distance
Print quality also depends on viewing distance: large posters seen from afar look fine at 100 to 150 dpi, while close-up photos need 300.
How the result changes with width
Holding every other input at the first worked example, this table changes only width. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Width | Resolution | Print size |
|---|---|---|
| 3000 | 12 MP | 10 × 13.33 in |
| 6000 | 24 MP | 20 × 13.33 in |
| 12000 | 48 MP | 40 × 13.33 in |
| 24000 | 96 MP | 80 × 13.33 in |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Width: entering "0" shows "Width must be greater than 0." beside that field and no result.
- Print resolution: entering "0" shows "Print resolution must be greater than 0." beside that field and no result.
Choosing between the Image Resolution Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Resolution Scale Calculator](/technology/resolution-scale/) | width, height and scale | Scaled resolution |
| [16:9 Aspect Ratio Calculator](/technology/16-9-aspect-ratio/) | Matching size | |
| [Screen Size Calculator](/technology/screen-size-calculator/) | diagonal, aspect ratio width and aspect ratio height | Screen size |
| [TV Mounting Height Calculator](/technology/tv-mounting-height/) | screen diagonal, aspect ratio width and aspect ratio height | Bottom edge height |
| [TV Height Calculator](/technology/tv-height-calculator/) | screen diagonal, aspect ratio width and aspect ratio height | Screen height |
Background: networking and display
Network speeds are quoted in bits per second and file sizes in bytes, and a byte is 8 bits, so a 100 Mbps link moves at most 12.5 megabytes per second; real throughput is usually below the advertised rate. Pixel density is the diagonal in pixels divided by the diagonal in inches: a 1920×1080 display of 24 inches is about 92 pixels per inch, and a 3840×2160 display of 27 inches about 163.
Assumptions and limitations
- Print quality also depends on viewing distance
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for width and print resolution to confirm this.
Frequently asked questions
How many megapixels is 4000 × 3000?
4000 × 3000 = 12,000,000 pixels, which is 12 MP.
What dpi for print?
300 is the usual standard.
Does dpi change the file?
No, it only sets print size.
What does the Image Resolution Calculator calculate?
Megapixels and print size of an image. It returns Resolution and Print size.
What formula does the Image Resolution Calculator use?
megapixels = width × height ÷ 10⁶; print size = pixels ÷ dpi. 300 dpi is a common target for photo prints.
What do I need to enter in the image Resolution Calculator?
You enter Width (px), Height (px) and Print resolution (dpi).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Print quality also depends on viewing distance.
What is an example of a image Resolution result?
With width 6000, height 4000 and print resolution 300, the resolution is 24 MP.
Related calculators
- Resolution Scale Calculator — Scaled resolution at a percentage.
- 16:9 Aspect Ratio Calculator — The missing dimension for a 16:9 frame.
- Screen Size Calculator — Width, height and area of a screen from its diagonal and aspect ratio.
- TV Mounting Height Calculator — Bottom and top edge height to center the screen at eye level.
- TV Height Calculator — Screen height from diagonal and aspect ratio.
- Aspect Ratio Calculator — Simplest aspect ratio of a width and height.
Sources
- OpenStax, Prealgebra 2e (Rice University): fractions, decimals, percents, ratios and rounding
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.