How to use the 4:3 Aspect Ratio calculator
Choose a mode
Resize by Aspect Ratio keeps 4:3. Calculate Aspect Ratio reads the ratio from two pixel sides.
Enter the numbers
The form opens at 4:3. Change the width or the height, or type both pixel sides.
Read the result
A width of 1024 is 768 tall at 4:3.
Summarize with
Slides, projectors and standard-definition TV
4:3 is the classic television and VGA shape. Early NTSC/PAL sets, 1024×768 XGA projectors and many slide decks still assume four units wide for every three tall. Photographers meet it as a cropped digital frame and as a print that matches older TV stills.
1024×768 and 800×600 are the named sizes on this site. Neither is HD. A presenter who stretches a deck sideways to fill a modern TV turns circles into ovals. Scale both sides together, or crop and pad. Do not stretch the picture.
A 4:3 classroom deck still looks “normal” on a 16:9 laptop only after you add side bars or zoom. Presenters who stretch slides to fill a TV make circles into ovals. Crop or pad instead.
Broadcast 4:3 and the VGA years
Broadcast 4:3 predates widescreen consumer TV. ITU-R BT.601 stored 720×480 or 720×576 with non-square pixels so the displayed picture still read as 4:3. Computer graphics standardized on VESA 4:3 modes such as 800×600 and 1024×768.
Do not treat VGA 640×480 as interchangeable with modern 4:3 photos. The ratio matches; the pixel budget and colour sampling do not.
Fitting a 16:9 master into a 4:3 screen
From 1920×1080, a 4:3 cut is 1440×1080 and a padded canvas is 1920×1440. Cut when the subject sits in the middle and the sides are unused. Pad when a logo is parked in a corner. Put a 4:3 aspect ratio on the brief only when the screen is actually this shape. Those sizes follow the floor-crop and ceil-pad rules on the methodology page.
Named 4:3 sizes on this site include 1024×768 and 800×600. Neither is HD. If you need broadcast-looking 4:3 from a 1920×1080 master, crop to 1440×1080 or pad to 1920×1440. Those integers are build-time fixtures, not guesses.
Next to 16:9, 4:3 is taller in the frame for the same width. Next to 3:2 it is slightly squarer. The portrait swap is 3:4, the same numbers rotated, and that page does not reuse this history.
Frequently asked questions
Is 1024×768 still worth targeting?
Only when the deck or the projector is actually 4:3. On a 16:9 laptop the same file shows side bars or gets cropped. The 4:3 aspect ratio did not become HD by scaling.
What is 4:3 from a 1920×1080 file?
Trim to 1440×1080, or pad to 1920×1440 if you cannot lose the edges. Do not stretch 1080 rows to 1440.
How is this different from a portrait poster?
Turn the numbers upright and you get 3:4, which owns flyers and phone portraits. This URL stays on the landscape TV shape.
Were old TV pixels square?
Often no. ITU-R BT.601 stored 720×480 or 720×576 with non-square pixels so the picture still read as 4:3. The pixel-aspect tool covers that case.