How Big is 18×24?

Dimensions of 18×24 are usually used for photos, posters, picture frames, store signs, notebooks, and aquariums.

Nobody said “18 x 24 inches” but when you say “18 x 24” people quickly think that you are talking about 18 x 24 inches. (Actually, the notebooks mentioned above are in centimeters, not in inches.)

What if you’re talking about 18 x 24 feet? How big are 18 x 24 feet, then?

It definitely expands the possibilities of what you can have with 18 x 24.

Read on to find out more.

How Big is 18 x 24 Inches?

The 18 x 24-inch dimensions are popularly used for photos, posters, picture frames, notebooks (in centimeters), store signs, and even aquariums for several reasons.


Even in the age of mobile phones, Instagram, and digital photos, people still like to have some of their favorite photographs printed.

Digital image resolution is expressed in pixels (or dots) across and pixels down, and the best printable resolution is 300 dots per inch (dpi). The digital size (4xD or 4×5.33) is the same aspect ratio as most digital cameras — 4:3 or 1.33 (1200 x 1600 pixels, 300dpi). Aspect ratios are the ratios of the width to the height of an image or screen.

The 18 x 24-inch (and 30 x 40-inch) images have the same 1.33 ratio and require no cropping for most digital cameras. This is why they are favorite photo sizes.


Dimensions of 18 x 24 inches are popular for posters that need to be seen both indoors and outdoors by people near or far. Less than these would mean they’d only be good for indoor settings, like with 8 x 11-inch letter sized-posters (good for flyers and handouts) and small 11 x 17-inch posters (indoor advertisements).

With medium-sized 18 x 24-inch posters, the maximum viewing distance is 15 feet. They fit well into regular poster frames, so you have plenty of poster design options.

how big is 18x24

Picture Frames

Artwork that is sized from 9 x 15 inches to 14 x 20 inches are best for 18 x 24-inch picture frames. These size frames also work great with digital prints since they have the same 4:3 (or 1:33) aspect ratio as many modern digital cameras.

Store Signs

Store signs with 18 x 24-inch dimensions are a popular choice for the same reasons posters of the same dimensions are: they can be used indoors and outdoors, and can be seen by people near or far — at least from as far as 15 feet away.


There are 18 x 24-cm. (7.08 x 9.44 inches) notebooks called royal notebooks in India or B5/composition notebooks elsewhere. They are best for school use, especially for young children who need a large enough space to practice their handwriting on but small and handy enough to carry around.


Aquariums are, of course, three-dimensional, so they come with not only length (L) and width (W) dimensions but also height (H). The 18 inches and 24 inches appear again as width and height dimensions in certain aquarium volume capacities.

Rectangular 65-gallon aquariums come in 36 x 18 x 24-inch (LWH) dimensions. Rectangular with squared corners 135-gallon aquariums come in 72 x 18 x 24-inch dimensions. Flatback hexagon aquariums come in 60 x 18 x 24-inch dimensions for 100-gallon tanks and 72 x 18 x 24-inch dimensions for 125-gallon tanks. Bow Vu (bowed front and corner) 120-gallon aquariums come in 60 x 18 x 24-inch dimensions.

How Big is 18 x 24 Feet?

Dimensions of 18 x 24 feet are commonly used for floor plans and tarpaulins, as well as for artwork prints and posters.

Floor Plans

House plans for 18 x 24 feet dimensions (432 square feet) are popular downloadable designs from the internet for small, one-bed-and-bath dwelling structures.


Tarpaulins come in many sizes, grade specs, and sheet weights. Grade specs are measured in grams per square meter (GSM) and sheet weights are measured in grams or kilograms. As a general rule, the heavier the grade specs and sheet weights, the more durable they are.

Tarpaulin sizes must come in certain grade specs and sheet weights to be able to handle potential their uses. An 18 x 24-feet tarpaulin comes in 12oz grade specs and 16kg. sheet weight. They are usually used as multi-purpose covering material.


When you see “18 x 24”, it doesn’t always mean that it’s in inches. It can be expressed in any unit of measurement.

In centimeters, it can be about school notebook measurements.

In inches, it can be about popular photos, posters, picture frames, store signs, and even part of aquarium measurements.

In feet, it can be about commonly used housing floor plans and tarpaulins used for covering.

It’s always best to check what “18 x 24” is about before making quick conclusions.

Nick Spieth