Without any doubt, A4 size is one of the most used paper formats both in printing and in our daily life, since it is the size of most of the sheets, notebooks, folders and other types of products that we frequently use in our daily life.
It is important to have a basic knowledge about the most popular sheet sizes and measurements, whether we have a company or we are dedicated to graphic design, as it is essential if we want to achieve the best possible result in our printing jobs.
In this article we are going to detail the characteristics of A4 size, its format expressed in different media units, the products in which it is most frequently used and answer some of the most frequently asked questions
What do A4 sheets look like?
A4 is part of a set or range of page sizes, called the ISO A or ISO 216 standard. This international standard is based on the German DIN 476 standard of 1922. In fact, A4 is often referred to as DIN A4. The Japanese have adopted the same range of paper sizes in their JIS P 0138-61 standard.
A4 measures 210 × 297 millimeters or 8.27 × 11.69 inches. In PostScript, its dimensions are rounded to 595 × 842 dots. Folded twice, an A4 sheet will fit in a C6-size envelope (114 × 162 mm).
By folding an A4 in two on its shorter side, an A5 document is created. Two A4 pages side by side on a sheet are equivalent to A3 paper size. This creates a range of paper sizes from A0 (which has a surface area of one square meter) to A10. The height/width ratio is kept constant for all sizes: 1:1.41 or the square root of 2. The dimensions are always rounded to the nearest millimeter.
Let’s describe different types of units of measurement used to express A4 size
Size A4 in centimeters
The measurements for A4 size in centimeters are 21.0 x 29.7 centimeters
In the following table you have the equivalence in micrometers, millimeters and meters, in case you find them useful.
| Measures | Micrometers | Millimeters | Centimeters | Meters | |
| Size A5 | 210000 x 297000 μm | 210 x 297 mm | 21,0 x 29,7 cm | 0,21 x 0,297 m |
DIN A4 size in pixels
For an image to output correctly, it must have a certain minimum resolution. The number of pixels depends on the required output quality.
- At 300 ppi (pixels per inch) the image must be 2480 x 3508 pixels. This is the resolution required for quality offset printing that will be viewed at close range (such as books, brochures, magazines, calendars,…). For photo books, this is also the optimal resolution, but a somewhat lower pixel count (250 ppi) is fine for high-quality photographs.
- At 150 ppi, the image should be 1240 x 1754 pixels. This is the minimum resolution for newspapers or posters viewed from a fairly close distance.
A digital camera with decent image quality and a resolution of 8 megapixels or more can be used to print high-quality A4-size photographs. A somewhat lower resolution is still valid.
A4 size in pixels per inch for low resolutions
This type of resolution is the most commonly used for conventional print jobs such as posters, books, brochures, catalogs, etc. For web images, resolutions of 72ppi or 96ppi are recommended.
For any printing job it is always recommended a resolution of at least 300ppi to get the best results, although you can also work with 150ppi, depending on the type of printing you want to do.
| Size in pixels | 72 PPI | 96 PPI | 150 PPI | 300 PPI |
| A4 | 595 x 842 px | 794 x 1123 px | 1240 x 1754 px | 2480 x 3508 px |
Pixels per inch for DIN A4 at medium resolutions
| Size in pixels | 600 PPI | 720 PPI | 1200 PPI |
| A4 | 4960 x 7016 px | 5953 x 8419 px | 9921 x 14032 px |
High resolutions for A4 in pixels per inch
Tamaño en pÃxeles por pulgada para resoluciones altas de 1440,2400 y 2880
| Size in pixels | 1440 PPI | 2400 PPI | 2880 PPI |
| A4 | 11906 x 16838 px | 19843 x 28063 px | 23811 x 33676 px |
A4 size in Thou, inches, feet and yards
Aunque no son las unidades de medidas más comunes que nos vamos a encontrar, si realizas algún trabajo de imprenta o de diseño gráfico a nivel internacional, quizás te sea útil esta tabla donde podrás encontrar las medidas del tamaño A4 en unidades como pulgadas, yardas o pies, muy usadas especialmente en paÃses angloparlantes.
| Unidad de medida | Thou | Pulgadas | Pies | Yardas |
| Tamaño A4 | 8268 x 11693 thou | 8.26 x 11.69 Pulgadas | 0.689 x 0.974 pies | 0.230 x 0.325 yd |
A4 size in Thou, inches, feet and yards
Sometimes we can find that certain types of printing presses and machinery use different measurement systems to those we are used to, in this table you have some of these measurement systems for A4 size.
| Unit of measure | Points | Spades | HPGL |
| Tamaño A4 | 595 x 842 | 49.6 x 70.2 Picas | 8400 x 11880 hp |
Frequently asked questions about A4 size
We will now answer some of the questions that many people often ask about the DIN A4 format.
On what type of products is A4 size typically used?
As we have already mentioned above, A4 is one of the most commonly used formats on a daily basis so it is very common to see it in products such as:
- Posters
- Books, notebooks, catalogs, magazines
- Folders
- Letters
Which size is larger A4 or A3?
A3 is a larger size than A4, to be more precise, one A3 sheet is equivalent to two A4 size sheets, just as one A4 sheet is equivalent to two A5 sheets.
The higher the A number the smaller the size, with the largest being DIN A0 and the smallest being DIN A10.
Why is it important to know the dimensions of DIN A4?
Whether you are a graphic designer or you are simply going to do any printing job, knowing the measurements of the format you are going to work with will allow you to get the best possible result when printing your work.
If, for example, you prepare a design in a very low resolution, not suitable for printing, the result will probably be worse than you expected.
Knowing in advance the pixel size of the main formats allows you to choose precisely the sizes you need to work with to ensure an optimal printing result.
If you want to know in detail the characteristics of the most commonly used sizes in printing and design, take a look at our section on sizes and measurements, where we describe everything you need to know about the main formats used in printing.