Video Resolution Calculator
Work out the exact dimensions for a video. Choose an aspect ratio – 16:9, 9:16 for vertical video, 4:3, square, 4:5, ultrawide or cinema formats – enter the width or the height, and get the matching resolution rounded to even numbers or to multiples of 8 or 16 as encoders prefer. The common standard resolutions for that ratio are listed alongside.
- Runs in your browser
- No sign-up
- Free to use
For example 3:2 or 1.6.
Most video encoders need even dimensions; multiples of 16 match the block size of H.264 and avoid padding.
How to use Video Resolution Calculator
- Choose the aspect ratio or enter a custom one.
- Choose whether you know the width or the height.
- Enter the value and the rounding.
- Read the resolution and the standard sizes.
Video Resolution Calculator features
Many ratios
Widescreen, vertical, square, cinema.
Custom ratios
Any ratio like 3:2 or 1.6.
Encoder rounding
Even, multiples of 8 or 16.
Exactness check
Shows how rounding changed the ratio.
Standard sizes
Common resolutions per ratio.
Private
Runs in your browser; nothing is uploaded.
When to use Video Resolution Calculator
- Setting up projects in video editors.
- Creating vertical video for Reels, TikTok and Shorts.
- Scaling recordings to a target width.
- Planning cinema or ultrawide deliveries.
Video Resolution Calculator FAQ
Why must dimensions be even?
The common 4:2:0 colour format stores colour at half resolution, so width and height must be divisible by two. Many encoders refuse odd sizes.
Why multiples of 16?
H.264 encodes in 16 × 16 macroblocks. Other sizes work but are padded internally, which wastes a little efficiency.
What does 9:16 mean?
Vertical video: 9 units wide and 16 high, such as 1080 × 1920.
Why is 2560 × 1080 called 21:9?
It is really 64:27 (2.37:1); “21:9” is a marketing name for ultrawide screens.
Can I enter any ratio?
Yes. Choose Custom and enter it as width:height or as a decimal.
Resolution and aspect ratio
A video’s resolution is its width and height in pixels; its aspect ratio is the relationship between them. Knowing one dimension and the ratio fixes the other, but real-world constraints complicate the arithmetic: dimensions must usually be even, many workflows prefer multiples of 8 or 16, and some ratios do not divide evenly into whole pixels.
The calculator computes the missing dimension and rounds both to the chosen step. It then reports the actual ratio of the rounded size, so you can see whether rounding changed the shape noticeably. For cinema ratios like 2.39:1, a small deviation is normal.
Standard resolutions exist for good reasons: devices, platforms and broadcast systems are designed around them. For each common ratio the tool lists the established sizes, from 360p to 8K for 16:9, the vertical sizes used on social platforms, and the DCI formats used in cinemas.
When converting between ratios, also consider how the picture fits: the Video Aspect Ratio Calculator shows the bars or cropping needed.
All calculations are exact and run in your browser.