Aspect Ratio Calculator
Simplify a ratio and scale to a target dimension.
- Simplified ratio
- 16:9
- Scaled dimensions
- 1280.00 × 720.00
Aspect Ratio Calculator simplifies a width and height into a standard ratio like 16:9 or 4:3, and scales dimensions to a target width or height while preserving that ratio. All math runs locally in your browser.
How it works
Enter a width and height to see the simplified ratio using the greatest common divisor. Then choose whether to scale by target width or target height, enter that value, and the tool calculates the matching dimension proportionally.
Benefits
- Simplifies any resolution to its standard ratio
- Scales either dimension while preserving proportions
- Useful for images, video, and UI layout sizing
- Calculates instantly with no upload required
Use cases
- Identify the aspect ratio name for a given resolution
- Resize an image to a target width without distortion
- Plan video export dimensions for a target height
- Check print dimensions match a photo's original ratio
Best practices
- Always scale by one dimension to keep proportions locked
- Round scaled dimensions to whole pixels for image exports
- Use the simplified ratio to pick standard container sizes
- Recalculate if the source width or height changes
Common mistakes
- Setting both target width and height independently, causing distortion
- Assuming similar resolutions always share the same ratio
- Rounding the ratio before scaling, which reduces precision
- Confusing display resolution with the underlying aspect ratio
Privacy
Dimensions are calculated entirely in your browser using local arithmetic. Aspect Ratio Calculator does not upload or store any image or video files.
Frequently asked questions
- How is the simplified aspect ratio calculated?
- The tool finds the greatest common divisor of the rounded width and height, then divides both by it—for example, 1920×1080 simplifies to 16:9.
- How does scaling to a target width or height work?
- The tool multiplies your target dimension by the original width-to-height ratio to compute the matching dimension, keeping the aspect ratio unchanged.
- Can I use decimal dimensions?
- Yes, width, height, and the target value all accept decimals. The simplified ratio is calculated from the rounded whole-number values for readability.
- What is this tool useful for?
- It is commonly used to resize images or video frames without distortion, or to identify the standard ratio name (like 16:9 or 4:3) for a given resolution.
- Does switching between scale-by-width and scale-by-height change the ratio?
- No. The simplified ratio only depends on the original width and height. The scale target only determines which dimension you provide and which one is calculated.
- Is my image or video data uploaded?
- No. Only the numeric dimensions you type are used, and all calculations happen locally in your browser.
Related tools
Statistics Calculator
math
Count, mean, median, mode, and stdev from a list.
- statistics
- mean
- median
- calculator
Percentage Calculator
math
Percent of, percent-of-total, and percent change.
- percentage
- percent-change
- calculator
- math
Prime Number Checker
math
Check primality and list primes up to a limit.
- prime
- number-theory
- calculator
- math
Age Calculator
math
Age in years, months, and days between two dates.
- age
- date
- calculator
- math
BMI Calculator
math
BMI and weight category in metric or imperial.
- bmi
- health
- calculator
- fitness
GPA Calculator
math
Weighted 4.0-scale GPA from grades and credits.
- gpa
- grades
- calculator
- education