Aspect Ratio Calculator
Enter a width and height to get their simplified ratio, or lock a ratio (16:9, 4:3, 9:16, 2.39:1…) and let the tool solve the missing side — with a live visual preview.
Your dimensions
Ratio locked: change one side and the other follows. Tap “Custom” for free mode.
Resize / scale
Scale the current dimensions keeping the ratio.
Result: —
Standard aspect ratios
The most common aspect ratios and their typical use. Tap a row to load it.
| Ratio | Decimal | Typical use |
|---|---|---|
| 1:1 | 1.00 | Square · social |
| 5:4 | 1.25 | |
| 4:3 | 1.33 | Classic · MFT |
| 3:2 | 1.50 | 35 mm photo |
| 16:10 | 1.60 | Laptops |
| 16:9 | 1.78 | HD / UHD video |
| 1.85:1 | 1.85 | Cinema flat |
| 2:1 | 2.00 | Univisium / streaming |
| 21:9 | 2.33 | Ultrawide monitor |
| 2.39:1 | 2.39 | Cinemascope · anamorphic |
| 9:16 | 0.56 | Vertical · mobile |
How aspect ratio is calculated
Aspect ratio compares the width of the frame to its height, reduced to its simplest form:
Divide width and height by their greatest common divisor and you get the ratio in lowest terms. To go the other way, lock a ratio and fixing one side solves the other while keeping the exact proportion — essential for rescaling without distorting or over-cropping. The live preview shows the shape of the frame instantly.
Example: the aspect ratio of 1920×1080
You have a 1920 × 1080 px image:
- GCD of 1920 and 1080 = 120.
- 1920 ÷ 120 : 1080 ÷ 120 = 16 : 9 (decimal 1.778).
- It is landscape and totals 2.07 megapixels.
In reverse: lock 16:9 and type a width of 2560 px → the calculator sets the height to 1440 px (QHD) automatically.