Aspect Ratio Resize Calculator

Work out aspect ratio resize instantly with clear inputs, formula shown and shareable results.

About Aspect Ratio Resize Calculator

Keeping the aspect ratio means the new height is the new width divided by the original width over height ratio. Pixel count changes with the square of the scale factor, so scaling to two thirds the width leaves only 44% of the original pixels.

Formulas

New height

new height = new width x original height / original width

Pixel change

pixels scale with the square of the linear scale factor

Worked example

With the default values below, Aspect Ratio Resize Calculator returns New height to keep the ratio of 720.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Original widthminimum 1 px: 1,920 px
Original heightminimum 1 px: 1,080 px
New widthminimum 1 px: 1,280 px

Results

New height to keep the ratio: 720.00 px
Aspect ratio as a decimal: 1.77778
Scale factor: 0.66667 x
Change in total pixels: -55.56%

Step by step

1Values used
2New height
3Pixel change
4New height to keep the ratio= 720.00 px
5Aspect ratio as a decimal= 1.77778
6Scale factor= 0.66667 x
7Change in total pixels= -55.56

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Aspect Ratio Resize figure worked out?

new height = new width x original height / original width. Keeping the aspect ratio means the new height is the new width divided by the original width over height ratio.

Why does this matter?

Pixel count changes with the square of the scale factor, so scaling to two thirds the width leaves only 44% of the original pixels.

What do I need to enter?

Enter original width, original height, new width. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.