4:3 Aspect Ratio: When and Why It Still Matters

4:3 Aspect Ratio: When and Why It Still Matters

Four-to-three dominated screens for sixty years. Every CRT television, early computer monitor, and standard-definition broadcast used it before widescreen formats took over. Its proportions come from the Academy aperture adopted by the Society of Motion Picture Engineers in 1932, which matched the width-to-height relationship of 35mm silent film. That standard outlasted its era,4:3 content remains active in security camera systems, institutional kiosk software, and video archives that never migrated to widescreen.

The practical implications of 4:3 today are straightforward: any 4:3 source playing on a 16:9 screen shows pillar bars, and any 16:9 source on a 4:3 screen shows letterbox bars. Knowing the exact pixel dimensions for both the source and target lets editors position overlays, subtitles, and graphics inside the correct safe zone. This guide covers 4:3 dimensions, its remaining use cases, and the conversion formulas for bridging it to modern displays.

History and where 4:3 still appears

The 4:3 ratio survived broadcast until the late 2000s, the US finished its NTSC-to-ATSC digital transition in 2009, ending over-the-air 4:3 standard definition.¹ Yet the ratio persists. Analog IP cameras and legacy CCTV recorders output 4:3 video at 480p or 600p. Training software designed in the 2000s for 1024×768 projectors still runs at 4:3 on institutional hardware. Many photo print labs accept 4:3 crops because digital cameras with 4:3 sensors, including all Micro Four Thirds cameras from Panasonic and OM System, produce 4:3 native files. Consequently, any workflow receiving assets from these sources needs 4:3 to widescreen conversion calculations.

Common 4:3 pixel dimensions

The 4:3 ratio was once the only resolution standard for computer displays and broadcast monitors, from the earliest IBM PCs through the LC and iMac lines of the late 1990s, and every pair in the standard ladder shares a greatest common divisor that reduces cleanly to four-to-three. The GCD reduction explains why these resolutions all share the same proportions: GCD(640,480) is 160, and both 640/160 and 480/160 reduce to four and three, with the same ratio applying at every step up the resolution ladder including the SVGA, XGA, and UXGA standards.

Legacy SD, early HD, and modern 4:3 sensors

Standard 4:3 resolutions include 640×480 (VGA), 800×600 (SVGA), 1024×768 (XGA), 1280×960, 1600×1200 (UXGA), and 2048×1536. Higher 4:3 resolutions appear on 10-megapixel and 12-megapixel Micro Four Thirds sensors, where a 12-megapixel sensor captures approximately 4032×3024 pixels at 4:3. Furthermore, web developers who support iPad users should note that the non-retina iPad Air (9.7 inch) displays at 1024×768, exactly XGA 4:3, and the same resolution appears on many institutional projectors still in service across schools and conference centers; converting any of these to 16:9 for widescreen output requires either a horizontal crop that discards vertical resolution or a pillarbox that preserves the original frame at a reduced width.

The calculator turns each of those resolutions into a widescreen plan. Enter 640×480 and it returns 4:3 with 240 pixels of pillar per side on a 1920×1080 display, enter 1024×768 and the same target shows the same 240-pixel bars, so you can decide before exporting whether to pillarbox the archive or accept the horizontal crop that a center cut removes.

Problems when 4:3 meets widescreen

Pillarboxing 4:3 content on 16:9 adds vertical bars. On a 1920×1080 display, a 4:3 video at full height is 1440 wide, leaving 240-pixel bars per side. On a 4K (3840×2160) display, the 4:3 sub-frame at full height is 2880 wide, leaving 480-pixel bars per side. These values matter for logo placement, title-safe zones, and PIP layouts in broadcast. Conversely, a center cut to 16:9 removes 240 pixels per side from a 1440-wide 4:3 source at 1080 pixels tall, aggressive for news content where the presenter may stand near the frame edge. The CapyToolkit letterbox calculator computes bar widths for any source-to-target ratio pair.

Micro Four Thirds cameras and the 4:3 capture advantage

Micro Four Thirds sensors from Panasonic (GH6, OM System OM-5) capture native 4:3 images at up to 25.2 megapixels (5776×4336).² The 4:3 ratio gives MFT cameras a taller frame than the 3:2 sensors in full-frame cameras, which is advantageous for portrait-oriented subjects and for video producers who crop to 16:9 in post.

Vertical room for 16:9 and 4:5 crops

A 4:3 MFT capture at 5776×4336 contains enough vertical resolution to crop a 3840×2160 16:9 region while retaining 83% of the original horizontal pixels. Full-frame 3:2 sensors at 6000×4000 lose 11% of their horizontal resolution when cropped to 16:9. The GH6 also offers a 5.7K open-gate recording mode at 5760×4320, which gives maximum flexibility for reframing in post-production; for photographers who shoot both stills and video, the 4:3 native ratio means less wasted crop area when switching between deliverables because the taller frame reduces the amount of content discarded during horizontal cropping.

Why security cameras still record at 4:3 in 2026

Analog SD CCTV systems using 480TVL or 600TVL sensors output 4:3 video at 704×576 (PAL) or 720×480 (NTSC). Many of these systems remain in operation because replacing cameras requires rewiring, reconfiguring DVR hardware, and retraining staff. The cost of a full IP camera migration ranges from $200 to $500 per camera, so facilities with 64 or more cameras face a $12,000 to $30,000 conversion expense.³

Modern IP cameras that still record at 4:3

Some modern IP cameras, including the Hikvision DS-2CD1043G2-I and the Dahua IPC-HFW1431S-A,⁴ still offer 4:3 recording modes at 4 megapixels (2560×1920) because the taller frame captures more vertical coverage in hallways and stairwells. When integrating these cameras into a modern VMS (video management system) that displays on 16:9 monitors, the VMS must either pillarbox the 4:3 feed or stretch it; most VMS platforms including Milestone XProtect and Blue Iris⁵ let you configure the display mode per camera.

When to use this

Use this when working with security camera footage, legacy training content, Micro Four Thirds camera files, or any video archive recorded before 2010. Also use it when planning a 4:3 to 16:9 center cut to check how much of the frame survives.

Examples