Aspect Ratio Calculator
Resize an image or screen while keeping its aspect ratio, or find the ratio of any width and height — for photos, video, and displays.
كيفية استخدام هذه الحاسبة
- 1Enter the original width and height.
- 2Choose whether you want a new height, a new width, or just the ratio.
- 3Enter the one new dimension you know, and the other is calculated to keep the proportions.
طريقة الحساب
Aspect ratio
ratio = width ÷ height new height = new width ÷ ratio new width = new height × ratio simplify width:height by their greatest common divisor
Aspect ratio is width divided by height, and keeping it constant is what stops an image looking stretched or squashed when resized. Fix one new dimension and the other follows directly from the ratio. Expressing the ratio in whole-number form — 1920×1080 as 16:9 — is done by dividing both by their greatest common divisor, which is why so many display sizes reduce to the same familiar ratios.
مثال محلول
A 1920×1080 image is a 16:9 ratio (1.778). To resize it to 1280 pixels wide while keeping the proportions, the height must be 1280 ÷ 1.778 = 720 pixels — which is exactly 1280×720, still 16:9.
Aspect Ratio Calculator: الدليل الكامل
Why proportions must be preserved
Aspect ratio is the relationship between an image's width and its height, and it is the single thing you must not change when resizing if you want the result to look right. Scale the width and height by different amounts and everything stretches or squashes — faces widen, circles become ovals, text distorts. Keeping the ratio constant means multiplying both dimensions by the same factor, which the calculator does by deriving one new dimension from the other.
This is why image editors have a 'lock aspect ratio' or 'constrain proportions' option, usually on by default. When it is on, typing a new width fills in the matching height automatically. This tool does the same arithmetic for cases where the software will not, such as planning a layout or specifying an export size.
The ratios you meet everywhere
A handful of ratios dominate because of standards and hardware. 16:9 is modern widescreen — nearly every TV, monitor, and HD or 4K video uses it (1920×1080, 3840×2160, and so on all reduce to 16:9). 4:3 is the older 'square-ish' standard of pre-HD television and many tablets. 3:2 comes from 35 mm film and is common in cameras; 1:1 is the square of social-media posts; and 9:16 is vertical video for phones.
Because these all reduce to the same small ratios via their greatest common divisor, wildly different pixel counts share a shape. 1280×720, 1920×1080, and 2560×1440 are all 16:9 and look identical in proportion — only sharper. Recognising the ratio, rather than the pixel dimensions, is what tells you whether two sizes are compatible.
Cropping and letterboxing change the ratio on purpose
Sometimes you do want to change the aspect ratio — fitting a 16:9 video onto a 4:3 screen, or a landscape photo into a square social post. There are two honest ways to do it, and both are different from the resize this calculator performs. Cropping removes part of the image to reach the new ratio, sacrificing content at the edges. Letterboxing (or pillarboxing) adds bars to preserve the whole image inside a different-shaped frame.
What you should almost never do is simply stretch the image to the new ratio, which is the distortion the resize here exists to prevent. If your target has a different shape from your source, decide deliberately between cropping and letterboxing rather than squashing — the proportion-preserving resize above is for when the target keeps the same shape and you only need it larger or smaller.
الأسئلة الشائعة
How do I resize an image without stretching it?
Keep the aspect ratio: multiply both dimensions by the same factor. Fix one new dimension and derive the other from the original ratio. For a 16:9 image, a new width of 1280 requires a height of 720 (1280 ÷ 1.778). This calculator does that for you.
What aspect ratio is 1920×1080?
16:9, the widescreen HD standard. Dividing 1920 and 1080 by their greatest common divisor (120) gives 16 and 9. Many other resolutions — 1280×720, 2560×1440, 3840×2160 — reduce to the same 16:9 ratio and look identical in shape.
What is the difference between resizing and cropping?
Resizing keeps the same aspect ratio and just makes the image larger or smaller. Cropping removes part of the image to change the ratio, sacrificing edge content. Stretching to a new ratio, which distorts the image, is a third option you should generally avoid.
Why do I get a decimal for the new dimension?
Because keeping the exact ratio rarely lands on a whole number of pixels. Round to the nearest whole pixel for the final size — a fraction of a pixel does not exist. The tiny rounding will not visibly affect the proportions.