Quick answer
For a 16:9 screen, height = width × 9 ÷ 16 and width = height × 16 ÷ 9. A width of 1280 gives a height of 720.
Enter either the width or the height. The calculator returns the matching size. Use this 16:9 aspect ratio calculator to check your own figures.
Related tools: Aspect Ratio Calculator: Simplest aspect ratio of a width and height. Resolution Scale Calculator: Scaled resolution at a percentage. Screen Size Calculator: Width, height and area of a screen from its diagonal and aspect ratio.
How to use the 16:9 Aspect Ratio Calculator
- Optionally, enter width (above 0).
- Optionally, enter height (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Width (optional) | A number | > 0 |
| Height (optional) | A number | > 0 |
Formula and method
Formula
height = width × 9 ÷ 16; width = height × 16 ÷ 9
IEEE-754 double precision; shown to the decimals indicated.
Enter either width or height.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Width = 1280.
| Result | Value |
|---|---|
| Matching size | 720 (height) |
Example 2
Inputs: Height = 720.
| Result | Value |
|---|---|
| Matching size | 1,280 (width) |
The first line is the headline result (matching size). IEEE-754 double precision; shown to the decimals indicated.
Common 16:9 sizes
1280 × 720 (HD), 1920 × 1080 (Full HD), 2560 × 1440 (QHD) and 3840 × 2160 (4K). Each has the same shape; the factor between them is the resolution.
Scaling
Enter exactly one value. To scale a 16:9 video to a width of 854, the height is 480. 16:9 is the standard for HD television and online video; 4:3 and 21:9 are other common ratios.
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 | Matching size |
|---|---|
| 640 | 360 (height) |
| 1280 | 720 (height) |
| 2560 | 1,440 (height) |
| 5120 | 2,880 (height) |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Width: left empty shows "Enter either the width or the height." beside that field and no result.
Choosing between the 16:9 Aspect Ratio 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 |
|---|---|---|
| [Aspect Ratio Calculator](/technology/aspect-ratio-calculator/) | width and height | Aspect ratio |
| [Resolution Scale Calculator](/technology/resolution-scale/) | width, height and scale | Scaled resolution |
| [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
- Enter exactly one value
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 to confirm this.
Frequently asked questions
What is 1920 wide at 16:9?
A 16:9 screen 1920 wide is 1920 × 9 ÷ 16 = 1080 high.
What is the decimal ratio?
The decimal ratio is 16 ÷ 9 = 1.7778.
What's the ratio of a phone screen?
Often 19.5:9 or 20:9.
What does the 16:9 Aspect Ratio Calculator calculate?
The missing dimension for a 16:9 frame. It returns Matching size.
What formula does the 16:9 Aspect Ratio Calculator use?
height = width × 9 ÷ 16; width = height × 16 ÷ 9. Enter either width or height.
What do I need to enter in the 16:9 Aspect Ratio Calculator?
You enter . Optional: Width and Height.
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Enter exactly one value.
What is an example of a 16:9 Aspect Ratio result?
With width 1280, the matching size is 720 (height).
Where does the method come from?
The method follows: Aspect ratio = width ÷ height; 16:9 is the HDTV proportion in ITU-R Recommendation BT.709.
Related calculators
- Aspect Ratio Calculator — Simplest aspect ratio of a width and height.
- Resolution Scale Calculator — Scaled resolution at a percentage.
- 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.
- TV Viewing Distance Calculator — Viewing distance for a chosen horizontal viewing angle.
- SLA Availability Calculator — Allowed downtime for an availability percentage.
- Server Uptime Calculator — Uptime percentage from downtime in a period.
- Base64 Encode/Decode — Encode text to Base64 or decode Base64 to text (UTF-8).
Sources
- Aspect ratio = width ÷ height; 16:9 is the HDTV proportion in ITU-R Recommendation BT.709
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.