WebToolsHUBHow to keep the right aspect ratio
- Pick a preset ratio (16:9, 4:3, 1:1, 9:16, 3:2, 21:9) or type your own ratio width and height.
- Enter the one dimension you already know — width or height.
- Read the missing dimension, shown as a whole pixel value with the exact figure underneath when it rounds.
- Fill in both real dimensions and the tool simplifies them to their cleanest ratio and flags any drift from the target.
- Watch the shape preview update so a 9:16 mistake never ships as a 16:9 upload.
Frequently Asked Questions
Why does my computed height come out with a decimal?
Because the exact ratio does not always land on whole pixels — 16:9 at width 1919 wants a height of 1079.44. The calculator shows the rounded pixel value and the exact figure so you can decide whether the sub-pixel drift matters for your layout.
What does simplifying a ratio mean?
Dividing both sides by their greatest common divisor: 1920×1080 simplifies to 16:9 because both share the factor 120. It turns real dimensions into the clean ratio they actually express — useful for spotting what an odd export size really is.
Which ratio should I use for which platform?
16:9 for standard video and YouTube, 9:16 for shorts, reels and stories, 1:1 for avatars and feed squares, 4:3 for classic presentations, and 21:9 for ultrawide cinematic work. The presets cover all of them.
Is my data stored or sent anywhere?
No. Every calculation runs locally in your browser the moment you type, and nothing is saved, logged or transmitted.
Why does the tool warn that my dimensions are off from the target?
If both real dimensions are entered, their actual ratio is compared with the target ratio; a drift above one percent is flagged. That catches the common case of a crop that was meant to be 16:9 but landed a few pixels short.