Aspect Ratio Calculator
Simplify aspect ratios and calculate matching dimensions.
This aspect ratio calculator simplifies a width-to-height ratio to its lowest terms, and can calculate a matching dimension needed to preserve that ratio when resizing an image, video, or screen.
Enter a width and height, and the calculator returns the simplified aspect ratio and any proportional dimension you need.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| 1920 × 1080 resolution | 16:9 | GCF(1920, 1080) = 120. 1920 ÷ 120 = 16, 1080 ÷ 120 = 9, giving 16:9. |
| 2560 × 1440 resolution | 16:9 | GCF(2560, 1440) = 160. 2560 ÷ 160 = 16, 1440 ÷ 160 = 9, giving 16:9 - the same standard ratio as the first example despite a higher resolution. |
Simplifying an Aspect Ratio
An aspect ratio is simplified by dividing both the width and height by their greatest common factor (GCF) - a 1920x1080 resolution has a GCF of 120, simplifying to 16:9, the standard widescreen ratio used by most modern displays and video content.
Finding a Proportional Dimension
To resize an image or video while preserving its aspect ratio, use: new height = new width x (original height / original width), or the reverse to solve for width - keeping this ratio constant prevents the stretching or squishing distortion that occurs when width and height are resized independently.
How to Use the Aspect Ratio Calculator
- Open the Aspect Ratio Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the aspect ratio calculator works.
Frequently Asked Questions
How do you calculate aspect ratio?
Divide the width by the greatest common factor shared with the height (or express as width:height), simplifying to the lowest whole-number ratio - for example, 1920x1080 simplifies to 16:9.
How do I resize an image without distorting it?
Calculate the new height (or width) using the original aspect ratio: new height = new width x (original height / original width), keeping the same proportional relationship between the two dimensions.
What is the most common video aspect ratio?
16:9 is the standard widescreen aspect ratio for most modern TVs, monitors, and online video, though older content commonly used 4:3, and cinema formats sometimes use wider ratios like 2.39:1.
How do I use this aspect ratio calculator?
Enter the known values, review the units or settings, and the calculator updates the result instantly. The formula and example on this page show how the answer is produced.
What does the Aspect Ratio Calculator calculate?
Simplify aspect ratios and calculate matching dimensions. It is designed for fast browser-based calculations without sign-up, downloads, or manual spreadsheet setup.
What formula does this aspect ratio use?
The formula is: ratio = width / height. The 16:9 widescreen standard now dominant across TVs, monitors, and online video was formally adopted by the ATSC (Advanced Television Systems Committee) in the 1990s as part of the shift to digital and HD television, chosen partly as a compromise ratio that worked reasonably well for both traditional 4:3 content and the wider cinematic aspect ratios film studios had used since the 1950s.
Related Calculators
Screen Size Calculator
Calculate screen width and height from diagonal and aspect ratio.
QR Code Size Calculator
Estimate printed QR code size from modules, pixel size, and quiet zone.
Percentage Calculator
Calculate percentages, percent of a number, and percentage changes fast.
Date Calculator
Calculate the number of days, weeks, or months between two dates.
Fuel Cost Calculator
Calculate trip gas cost based on distance, vehicle MPG, and fuel price.
Age Calculator
Find your exact age in years, months, and days from your date of birth.
Last updated: September 27, 2026.