Video & Canvas Aspect Ratio Scaling Calculator
Solve a missing width or height at an exact ratio, or calculate letterbox and pillarbox padding to fit content into a canvas without cropping.
1920×1080
Solved at your exact 16:9 ratio.
| Metric | Value |
|---|---|
| Content width | 1920 px |
| Content height | 1080 px |
| Bar mode | none |
| Bar thickness each side | 0 px |
Why solving the missing dimension needs an exact ratio, not a rounded one
Rounding a ratio to a decimal before scaling (say, treating 16:9 as exactly 1.78) introduces a small but real distortion that compounds at scale — a 1920px-wide image scaled at 1.78 instead of the exact 16÷9 fraction lands a fraction of a pixel off from a true 16:9 frame. This tool keeps the ratio as an exact fraction throughout the calculation and only rounds the final displayed value.
Why fitting content into a different-ratio canvas always leaves bars somewhere
Filling a 9:16 canvas completely with 16:9 source footage would require cropping the sides off, stretching the image non-uniformly, or both — neither preserves the original composition. Fitting without cropping means scaling uniformly until one axis exactly matches the canvas, which leaves the other axis short by definition and creates bars — letterbox (top/bottom) when content is proportionally wider than the canvas, pillarbox (left/right) when it's proportionally narrower.
Why this matters for repurposing content across platforms
The same piece of video routinely needs to go out as 16:9 (YouTube), 9:16 (Shorts/Reels/TikTok), 1:1 (feed posts) and 4:5 (some feed placements) from a single source — and each reformat either crops content out, or preserves the whole frame with bars. Knowing the exact padding in advance lets you design the shot (keeping important content centered) so cropping doesn't cut anything critical, or plan the bar color/branding deliberately instead of it defaulting to plain black.
How to use this calculator
- Choose solve-dimension mode or fit-canvas mode.
- Enter your target ratio and known dimension or canvas size.
- See the solved dimension, or the fitted content size and bar thickness.
- Exact proportional scaling
- The missing dimension is solved so width ÷ height exactly equals your target ratio — no rounding is applied until the final displayed value.
- Fits without cropping, never stretches
- The content is scaled uniformly to the largest size that fits entirely inside the canvas at its exact source ratio — it's never stretched non-uniformly and never cropped, which is why bars appear on the shorter axis instead.
Questions
Why does fitting 16:9 footage into a 9:16 canvas leave bars instead of filling the frame?
Because filling a 9:16 frame completely with 16:9 source would require cropping the sides off, stretching the image non-uniformly, or both — neither preserves the original composition. Fitting without cropping means scaling uniformly until one axis matches the canvas, which leaves the other axis short and creates bars on that shorter axis by definition.
What's the actual difference between letterboxing and pillarboxing?
Letterbox bars run horizontally (top and bottom) and appear when the content is proportionally wider than the canvas — classic widescreen movies on an old 4:3 TV. Pillarbox bars run vertically (left and right) and appear when the content is proportionally taller/narrower than the canvas — vertical phone video played on a horizontal screen. Same underlying math, opposite axis.
Can I use this to figure out what resolution to export at for a specific ratio?
Yes — enter your target ratio and one known dimension (say, a fixed width your platform requires), and the tool solves the matching height that keeps the ratio exact, rather than you rounding a decimal by hand and introducing a slight distortion.
Does this tool actually resize or export anything?
No — it's a calculator, not an image or video processor. It tells you the exact dimensions and padding to use; applying that in your editing software or export settings is a separate step.