Aspect Ratio Calculator
Calculate aspect ratios, resize dimensions, and find GCD proportions online.
- 100% free
- Private in browser
- No signup
- No watermarks
1. Original Ratio (W1 : H1)
2. Calculate New Proportional Dimensions (W2 × H2)
Visual Proportion Box
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About Aspect Ratio Calculator
Aspect Ratio Calculator on TheToolss helps designers, video editors, and web developers calculate proportionate dimensions, scale images and videos, and find simplified aspect ratios (e.g. 1920x1080 = 16:9). Includes instant presets for YouTube, Instagram, TikTok, and ultrawide screens.
How to use Aspect Ratio Calculator
- Enter your original width (W1) and height (H1).
- Enter your new target width (W2) to find target height (H2), or vice versa.
- Click any standard preset (16:9, 4:3, 1:1, 9:16, 21:9) to auto-fill common ratios.
- View the simplified aspect ratio and live visual shape preview.
Key features
- Calculates missing width or height while locking proportional ratio
- Calculates exact simplified ratio (e.g. 16:9, 3:2, 21:9) using GCD
- Popular preset ratios for YouTube, TikTok, Instagram, and Cinema
- Live visual preview box showing the rendered proportions
- 100% private in-browser tool
Frequently asked questions
- What is the standard aspect ratio for YouTube videos and 1080p?
- The standard widescreen ratio for 1080p (1920x1080) and 4K (3840x2160) is 16:9.
- What is the aspect ratio for TikTok and Instagram Reels?
- Vertical video formats use 9:16 (such as 1080x1920).
- What does the Aspect Ratio Calculator give me?
- It works out Aspect Ratio, Decimal Ratio and Scaled Size, updating live as you change the inputs.
- What do I need to enter?
- Just Width 1, Height 1, New Width and New Height. Every field has a sensible default you can start from.
- Is my data uploaded anywhere?
- No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
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