What Is the 4:3 Aspect Ratio?
The 4:3 aspect ratio — also written 4×3 — means the width is four units for every three units of height. In decimal form that is 1.333:1. A 4:3 image or screen is wider than it is tall, but only by about a third: a 4:3 rectangle is one-third wider than it is high.
For decades 4:3 was the shape of almost every television, computer monitor, and photo print in the world. It was the standard-definition broadcast format, the shape of the original iPhone display, and the native aspect ratio of many digital cameras and tablets. It's also called "fullscreen" (in contrast to 16:9 "widescreen") — a holdover from the era when the only alternative on TV was a letterboxed film.
The 4:3 ratio is sometimes confused with 5:4 (1.25:1), which was used for a smaller set of LCD monitors and photo prints. The two are similar but not the same; this calculator uses 4:3 exactly.
Where 4:3 Is Used
- Legacy television content — almost all TV shows, news broadcasts, and cartoons produced before the mid-2000s were filmed or broadcast in 4:3.
- Older computer monitors and projectors — many projectors still default to 4:3 (often at XGA 1024×768), especially in classrooms and conference rooms where older A/V equipment is in use.
- Presentations and slides — PowerPoint's default slide size used to be 4:3, and many older deck templates still use it. Modern PowerPoint defaults to 16:9.
- Tablets and e-readers — the original iPad display was 4:3, and many tablets and e-readers still use a 4:3 panel.
- Digital cameras — most point-and-shoot and mirrorless cameras offer a 4:3 capture mode (Micro Four Thirds sensors are natively 4:3).
- Retro gaming — Super Nintendo, Game Boy, PlayStation 1, and many other classic consoles output 4:3.
Common 4:3 Resolutions
These are the most widely used 4:3 pixel dimensions, from the earliest CRT standard to high-resolution 4:3 displays.
| Name | Resolution | Pixel count | Typical use |
|---|---|---|---|
| VGA | 640 × 480 | 307,200 | Earliest PC standard; legacy video |
| SVGA | 800 × 600 | 480,000 | Older projectors; low-res presentations |
| XGA | 1024 × 768 | 786,432 | Most common 4:3 projector resolution |
| SXGA+ | 1400 × 1050 | 1,470,000 | Older LCD monitors; high-res projectors |
| UXGA | 1600 × 1200 | 1,920,000 | Large 4:3 monitors and photo prints |
| QXGA | 2048 × 1536 | 3,145,728 | High-res 4:3 displays and scans |
4:3 vs 16:9
The main reason 4:3 still comes up today is that most modern screens are 16:9 (1.778:1) — noticeably wider than 4:3. When 4:3 content is displayed on a 16:9 screen, it appears with vertical black bars on the left and right, called pillarboxing. That is the opposite of letterboxing (horizontal bars on a 4:3 screen when 16:9 content is shown).
Neither format is inherently better — it depends entirely on the content. 4:3 suits portrait-oriented subjects, older media, and presentations where a squarer slide feels natural. 16:9 suits landscapes, modern video, and anything designed for widescreen viewing. The practical rule: match the ratio to the content's native shape and the destination display's format, not the other way around.
How to Calculate 4:3 Dimensions
Any 4:3 dimension can be calculated from any other by multiplying or dividing by 4/3 (about 1.333). If you know the width and want the height, divide by 1.333; if you know the height and want the width, multiply by 1.333. The calculator above does this automatically and also reports total pixel count and diagonal length.
To scale a 4:3 image from one size to another, multiply both dimensions by the same factor. For example, going from 640×480 to 1280×960 is a factor of 2 on each side. The ratio stays 4:3 as long as both dimensions are scaled by the same amount.
Common Mistakes
- Stretching a 16:9 image to fill a 4:3 frame. This distorts faces and objects. If you must fill a 4:3 frame with 16:9 content, crop the sides or letterbox with bars instead of stretching.
- Confusing 4:3 with 5:4. They're close in appearance — 5:4 is 1.25:1, 4:3 is 1.333:1 — but not interchangeable. A 1280×1024 image is 5:4, not 4:3, even though it's often filed under "standard."
- Assuming "fullscreen" on a DVD means 4:3. DVD packaging uses "fullscreen" for a 4:3 pan-and-scan of a widescreen film. The original film was almost certainly wider.
- Using a 4:3 slide deck for a 16:9 projector. The slides will be pillarboxed with black bars. Modern projectors are almost always 16:9, so 16:9 is the safer slide size unless you know the projector is 4:3.
- Forgetting that retro gaming uses non-square pixels. 4:3 is the correct display aspect ratio, but old game consoles output non-square pixels. Emulators handle this via pixel aspect ratio correction — 4:3 describes the display shape, not the raw pixel grid.
Why Use a 4:3 Calculator?
Calculating 4:3 by hand is easy for round numbers (a 640-wide image is 480 tall), but breaks down for non-standard sizes or when converting from another ratio. This calculator handles any input — enter a width or height and the matching dimension appears instantly, along with total pixel count and diagonal. It's useful for resizing slides, preparing images for older projectors, converting between 4:3 and other ratios, or checking whether an image is genuinely 4:3 or just close to it.
