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Utility Calculators

Image Resize Dimensions Calculator

Verified formula Updated Jun 2026 Private — runs on your device

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px
px
px
Verified formula Private

New height (keeps aspect ratio)

720

For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.

How to use the Image Resize Dimensions Calculator

The Image Resize Dimensions Calculator works out your new height (keeps aspect ratio) in an instant. Enter original width, original height and new width and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.

  1. Enter the original width.
  2. Enter the original height.
  3. Enter the new width.
  4. Read off your new height (keeps aspect ratio) — the calculator updates automatically, with no button to press.

Formula

The Image Resize Dimensions Calculator uses the formula:

New height (keeps aspect ratio) = New width × Original height ÷ Original width

Worked example

For example, with original width of 1,920 px, original height of 1,080 px and new width of 1,280 px, the new height (keeps aspect ratio) is 720.

Inputs used
Original width 1,920 px
Original height 1,080 px
New width 1,280 px
Results
New height (keeps aspect ratio) 720

Results are estimates for educational use, not professional advice.

Frequently asked questions

Keep the aspect ratio: new height = new width × original height ÷ original width. A 1920×1080 image at 1280 wide becomes 720 tall.

It is the proportion of width to height. Keeping it constant prevents the image from stretching or squashing.

Yes, the same idea applies in reverse: new width = new height × original width ÷ original height.

Shrinking is usually fine; enlarging beyond the original size can look soft because new pixels are interpolated.

The Image Resize Dimensions Calculator uses the formula: New height (keeps aspect ratio) = New width × Original height ÷ Original width. For example, with original width of 1,920 px, original height of 1,080 px and new width of 1,280 px, the new height (keeps aspect ratio) is 720.

Enter the original width. Enter the original height. Enter the new width. Read off your new height (keeps aspect ratio) — the calculator updates automatically, with no button to press.

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