About

Content displayed with incorrect dimensions results in distortion, stretching, or "letterboxing" (black bars). This tool solves that risk by calculating the exact pixel dimensions required for any aspect ratio. Whether resizing for a cinema display or a social media feed, precise mathematics ensures visual fidelity.

We utilize the Euclidean algorithm to simplify fractions and standard cross-multiplication to derive missing variables. For example, if maintaining a 16:9 ratio, changing the width W automatically constrains the height H to maintain geometric proportion.

Formulas

The relationship between width W and height H is governed by the aspect ratio r_w:r_h. The fundamental equation for proportionality is:

WH = r_wr_h

To solve for Height H when Width is known:

H = W × r_hr_w

To reduce a resolution to its simplest Aspect Ratio (e.g., 1920:1080 → 16:9), we divide both dimensions by their Greatest Common Divisor (gcd):

ratio = Wgcd(W, H) : Hgcd(W, H)

Reference Data

Standard	Resolution (px)	Ratio	Usage
SD (NTSC)	640 × 480	4:3	Old TV broadcasts
HD (720p)	1280 × 720	16:9	Streaming, Broadcast
FHD (1080p)	1920 × 1080	16:9	Blu-ray, YouTube Standard
QHD (2K)	2560 × 1440	16:9	Gaming Monitors
UHD (4K)	3840 × 2160	16:9	Modern TVs, High-end Streaming
Cinema 4K	4096 × 2160	19:10	Digital Cinema
Instagram Square	1080 × 1080	1:1	Social Media Posts
Instagram Portrait	1080 × 1350	4:5	Social Media Feed
Ultrawide	3440 × 1440	21:9	Immersive Gaming
8K UHD	7680 × 4320	16:9	Future Broadcasts

Frequently Asked Questions

Using mismatched ratios forces the display to either crop the image (losing content at the edges), stretch the image (distorting shapes), or add padding (black bars, known as letterboxing or pillarboxing).

You can determine the ratio by dividing the width by the height. For example, 1920 / 1080 equals 1.777, which is the decimal equivalent of 16/9. This tool includes a "Detect from Image" feature to do this automatically.

Yes. 1920 divided by 1080 simplifies to 16/9. However, purely mathematical ratios don't account for "Pixel Aspect Ratio" (PAR), a legacy concept from analog TV where pixels weren't perfectly square. Modern digital screens almost universally use square pixels (PAR 1:1).

Height = (Width * RatioHeight) / RatioWidth. For a 16:9 screen with 1000px width: Height = (1000 * 9) / 16 = 562.5px.

1366x768 is technically approximately 683:384, which is very close to 16:9 but not exact. Manufacturers use this resolution to optimize manufacturing costs and memory addressing, accepting a microscopic amount of non-noticeable aspect distortion.