Resolution Scale Calculator

Resize a resolution proportionally, for example 1920 × 1080 to 1280 wide, and get encoder-friendly dimensions.

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How to use the Resolution Scale Calculator

  1. Enter the original width.
  2. Enter the original height.
  3. Choose the scale by.
  4. Enter the target width.
  5. Enter the target height.
  6. Enter the scale.
  7. Tick Round to even numbers (needed by most video encoders) if it applies.
  8. Press Calculate. The result updates automatically as you type.

About the Resolution Scale Calculator

Whenever you export a video for a different platform, create thumbnails or set a game's render resolution, you need dimensions that keep the original shape. This calculator scales both sides by the same factor and shows how the pixel count, and therefore file size and processing load, changes.

Most video codecs using 4:2:0 chroma subsampling require even widths and heights, and some hardware encoders prefer multiples of 8 or 16. Rounding to even numbers can shift the aspect ratio by a hair; the calculator warns you when the change is noticeable. Upscaling never adds real detail, so scale down from the highest-quality source when possible.

Formula

Scale factor = Target width ÷ Original width (or Target height ÷ Original height)
New width = Original width × Scale, New height = Original height × Scale
Pixel count change = (New W × New H) ÷ (Old W × Old H) − 1

Scaling 1920 × 1080 to 1280 wide is a factor of 0.667, giving 1280 × 720. Pixel count falls by 55.6%, because any linear scale changes the area by the square of the factor (0.667² ≈ 0.444).

Example calculation

Using the default values:

  • Original width = 1920 px
  • Original height = 1080 px
  • Scale by = Target width
  • Target width = 1280 px

the calculator returns:

  • New resolution: 1280 × 720
  • Linear scale: 66.67%
  • Pixel count change: -55.6%
  • New size: 0.922 megapixels

Frequently asked questions

What is 1080p scaled by 50%?

960 × 540, which has one quarter of the original pixels.

Why must video dimensions be even?

With 4:2:0 color subsampling, color is stored for each 2 × 2 block of pixels, so odd widths or heights cannot be encoded cleanly.

What is 4K downscaled to 1440p?

3840 × 2160 scaled to 1440 high is 2560 × 1440, a factor of two thirds.

Last updated: · Category: TV & Video calculators

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