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Keep the proportions.

Aspect Ratio Calculator

Find an image’s width-to-height ratio and calculate proportional dimensions for a new width or height without stretching the image.

Find a simplified ratio, then calculate a matching width or height.

Use the same units for both sides. Pixel dimensions are rounded for display.

SIMPLIFIED ASPECT RATIO

HOW IT WORKS

01

Enter the original width and height in the same unit.

02

Check the width-to-height ratio.

03

Enter a new width or height to find its proportional partner.

Shape is separate from size

Aspect ratio compares width with height. A 4,000 × 3,000 image and a 1,200 × 900 image both have a 4:3 ratio. Their shape matches even though their available detail is different.

Enter whole-number original dimensions. Dividing both sides by their greatest common divisor gives the simplest exact ratio. Keep the same units on both sides. For dimensions containing decimals, multiply both values by the same power of ten until they are whole numbers.

Resize without stretching

To preserve a 4:3 image at a width of 1,600 pixels, calculate 1,600 × 3 ÷ 4 = 1,200 pixels high. Replacing the height with 1,000 would change the shape unless you crop or add space.

Common print sizes do not all share a ratio. A 4 × 6 print is 2:3 in portrait orientation, while an 8 × 10 print is 4:5. A proportional resize alone cannot convert one into the other without a composition decision.

A FEW HELPFUL ANSWERS

Before you get started.

Does 3:2 mean the same thing as 2:3?

They are the same proportions rotated by 90 degrees. In width-to-height notation, 3:2 is landscape and 2:3 is portrait.

Why can the calculated pixel dimension need rounding?

A proportional calculation can produce a fraction, but a raster image needs whole pixels. Rounding one dimension can produce a tiny ratio difference. Use the exported pixel dimensions when making a final check.

Will matching the ratio guarantee a sharp print?

No. Matching the ratio prevents an unwanted shape change. You still need enough retained pixels for the physical size and a source image with useful detail.

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