ConversionsPS-05
How many pixels is A4? A chart by dpi, how the calculation works, and how to make print data
The pixel count of A4 is fixed only once you choose a dpi. We show the answer for each dpi in a table first, then explain how the calculation works and how to make print data, step by step.
In this article (14 sections)
- Conclusion: How many pixels is A4 at each dpi?
- How do you get A4 pixel counts with the calculator?
How do you calculate the pixel count of A4?2
- How does the A4 pixel count change with the use?
- How does the A4 pixel count compare with nearby paper sizes?
- How does the A4 pixel count change between portrait and landscape?
How do you make print data from the A4 pixel count?3
How do you set the A4 pixel count in each app?3
- Is a smartphone photo's pixel count enough for A4?
- What are the common mistakes with A4 pixel counts?
- What terms come up with A4 pixel counts?
What else should you know along with A4 pixel counts?3
A4 pixel count: frequently asked questions6
- Sources
The pixel count of A4 cannot be given as a single number. Paper size is defined in mm. Pixels are the number of "dots" on a screen or in image data.
Even for the same A4 sheet, the count changes with the number of dots you place in one inch (25.4mm). This dot density is called dpi.
The general guidelines are as follows:
- Viewing on a screen only: 72 to 96dpi
- Home printer: 200 to 300dpi
- Sending to a print shop: 300 to 350dpi
Here is the key point. Once you decide where the image will be used, the pixel count you need comes down to one number.
This article covers the following:
- A4 pixel counts by dpi (table)
- How the calculation works (mm ÷ 25.4 × dpi)
- The dpi each use needs
- Orientation, and how A4 compares with nearby paper sizes
- How to make print data that includes margins and bleed
- Settings in Word, Excel, PowerPoint, Canva and Photoshop
- How smartphone photo pixel counts relate to A4
- Common mistakes
Dimensions are shown in tables based on the standards (ISO 216 and JIS P 0138).
Conclusion: How many pixels is A4 at each dpi?
The pixel counts of A4 are shown in the table below. The standard for printing is "px (300dpi)", and the old standard for screens is "px (72dpi)".
| Size | A4 |
|---|---|
| Series | A |
| mm (w × h) | 210 × 297 |
| cm | 21 × 29.7 |
| inches | 8.27 × 11.69 |
| px (72 dpi) | 595 × 842 |
| px (150 dpi) | 1240 × 1754 |
| px (300 dpi) | 2480 × 3508 |
| px (350 dpi) | 2894 × 4093 |
| Typical use | Office paper, documents |
Source: JIS P 0138, ISO 216, ANSI/ASME Y14.1
The px values in the table are in "width × height" order. They are for portrait orientation (the shorter side as the width). For landscape, simply swap the width and height.
If you are not sure which to use, choose as follows:
- Only showing it on a screen (slides, the web, viewing a PDF): 72dpi or 96dpi is enough
- Printing on a home printer: text and figures are readable at 150dpi. For photos, 200 to 300dpi is safe
- Sending to a print shop: use 300dpi as the baseline. Match 350dpi if the shop asks for it
For values not in the table, such as 96dpi, 200dpi and 600dpi, use the calculator below.
How do you get A4 pixel counts with the calculator?
Choose the paper and the dpi in the tool above to get the A4 pixel count. Setting the orientation to "Landscape" swaps the width and height.
The tool runs entirely in your browser. The values you enter are not sent anywhere. Even without JavaScript, you can get the same values from the table above and the calculation below.
How do you calculate the pixel count of A4?
The pixel count of A4 comes from a single formula: "side length (mm) ÷ 25.4 × dpi".
- Pixel count = side length (mm) ÷ 25.4 × dpi
25.4 is one inch expressed in mm. dpi (dots per inch) is the number of dots per inch. Convert the side length to inches and multiply by the dpi, and you get the number of dots.
For the short side of A4, the calculation looks like this:
- 300dpi: 210 ÷ 25.4 × 300 = 2480.3 → 2480px
- 350dpi: 210 ÷ 25.4 × 350 = 2893.7 → 2894px
- 96dpi: 210 ÷ 25.4 × 96 = 793.7 → 794px
- 600dpi: 210 ÷ 25.4 × 600 = 4960.6 → 4961px
The long side uses the same formula.
- 300dpi: 297 ÷ 25.4 × 300 = 3507.9 → 3508px
- 600dpi: 297 ÷ 25.4 × 600 = 7015.7 → 7016px
Depending on how fractions are rounded, some guides differ by 1px, for example 2480 vs. 2481, or 3507 vs. 3508.
At 300dpi, 1px is about 0.08mm. It makes no difference to the printed result.
Here is the key point. Matching the dpi to the use matters more than chasing a 1px difference.
How is dpi different from ppi?
ppi is the density of pixels in image data, and dpi is the density of dots a printer lays down. Both are "a number per inch."
Canon's photo glossary describes dpi as "a unit of density that shows how many dots there are in one inch."
When you create image data, it makes no difference whether the setting is labeled ppi or dpi. Enter the same number and you get the same result. This article uses dpi, the term more people search for.
Where do 72dpi and 96dpi come from?
72 and 96 come from screen conventions. They are not standards for printing on paper.
In printing, 1 point (a unit of type size) is 1/72 of an inch. 72dpi is an old screen standard that was matched to this.
The web standard (CSS) defines 1 inch as 96px. 96 is also widely used as the baseline for computer screens.
This is why 72 and 96 show up for images meant for screens.
How does the A4 pixel count change with the use?
To get the A4 pixel count, first decide the dpi each use needs. The guidelines are shown in the table below.
| Use | Guideline dpi | Basis |
|---|---|---|
| Viewing on screen (web, slides, viewing a PDF) | 72 to 96 | CSS definition (1 inch = 96px), Canon's glossary (72dpi for web use) |
| Documents and figures printed on a home inkjet | 150 to 200 | Enough to read text and lines. For photos, use the next row |
| Photos printed on a home inkjet | 200 to 300 | Canon's print lessons (200 to 300ppi for inkjet) |
| Color printing sent to a print shop | 300 to 350 | Canon's print lessons (300 to 350ppi for commercial printing), Epson's FAQ (300 to 360dpi) |
| Black-and-white line art and small text | 600 | When you want smooth line edges. Not needed for photos |
Print shops ask for 350dpi because an A4 sheet is held in the hand and viewed up close.
Canon's print lessons explain it as follows:
- A4 and smaller are viewed up close. Below 300ppi, the detail is not quite sharp enough
- A3+ looks fine at 240ppi, and A2 at 200ppi
Posters get by with a lower dpi because they are viewed from a distance.
Note: Raising the dpi does not add detail that was not in the data. If you "convert" a small image to 350dpi, it stays blurry and only gains more dots. Check the pixel count of the original image before deciding on the dpi.
How does the A4 pixel count compare with nearby paper sizes?
Placing A4 next to A3, A5 and B5 shows how their pixel counts relate. A3 has twice the area of A4.
| Size | mm (w × h) | inches | px (150 dpi) | px (300 dpi) | px (350 dpi) |
|---|---|---|---|---|---|
| A3 | 297 × 420 | 11.69 × 16.54 | 1754 × 2480 | 3508 × 4961 | 4093 × 5787 |
| A4 | 210 × 297 | 8.27 × 11.69 | 1240 × 1754 | 2480 × 3508 | 2894 × 4093 |
| A5 | 148 × 210 | 5.83 × 8.27 | 874 × 1240 | 1748 × 2480 | 2039 × 2894 |
| B5 | 182 × 257 | 7.17 × 10.12 | 1075 × 1518 | 2150 × 3035 | 2508 × 3541 |
Source: JIS P 0138, ISO 216, ANSI/ASME Y14.1
As the table shows, the long side of A4 is the short side of A3. In pixels too, "A4 height = A3 width."
A5 works the other way. The short side of A4 is the long side of A5.
Suppose you enlarge A4 data to A3 and keep the same dpi. You need about 1.41 times (√2 times) as many dots both horizontally and vertically. You can get the ratio from "enlargement/reduction ratio" in the calculator above.
B5 here is the Japanese standard (JIS) size, a little smaller than A4. ISO B5 has different dimensions. When you choose B5 in software made outside Japan, check the numbers.
How does the A4 pixel count change between portrait and landscape?
Between portrait and landscape, the width and height of A4 swap. The total number of pixels stays the same.
As the figure shows, A-series paper has a short-to-long side ratio of 1 : √2 (about 1 : 1.414). This ratio is set by ISO 216 and JIS P 0138.
Folding the sheet in half keeps the same ratio.
If you will use A4 in landscape, create the data in landscape from the start, with "width = long side." If you rotate data made in portrait to landscape, some software adds margins. Some also shrinks it.
Photos from smartphones and cameras have a ratio of 4 : 3 or 3 : 2. That does not match A4's 1 : 1.414.
To fill a whole A4 page, you will have to crop (trim) somewhere. Assuming you will crop, prepare a few more pixels than the minimum.
How do you make print data from the A4 pixel count?
For print data, the A4 pixel count is the finished size plus bleed and margins. The finished size alone is sometimes not enough.
This is because printing needs "extra" space both outside and inside the finished size.
What is bleed, and how do you calculate it?
Bleed is the extra artwork you extend beyond the finished size when color or photos run to the edge of the paper.
It prevents white edges from appearing when the cutting (trimming the paper) is slightly off. Follow the width your print shop specifies. In Japanese printing, 3mm is widely used.
To calculate it, add the bleed width twice (once for each side) to each dimension, then use the same formula. For 3mm:
- Width: (210 + 3 × 2) ÷ 25.4 × 300 = 2551.2 → 2551px
- Height: (297 + 3 × 2) ÷ 25.4 × 300 = 3578.7 → 3579px
Here is how software handles it:
- Canva: when you download as "PDF Print", you can add crop marks (cutting guides) and bleed
- Photoshop: create the new document at a size that already includes the bleed
How do you decide the margins?
Margins are the space that keeps text and important artwork away from the edge of the paper. They depend on the printer's printable area and on your print shop's specifications.
Home printers have a strip along the edge of the paper that they cannot print on. Its width varies by model. Check "printable area" in your printer's manual.
Word's default margins are 1 inch (25.4mm) on the top, bottom, left and right. You can change them under Layout > Margins.
The same formula works when you think about margins in pixels. At 300dpi, 1mm is about 11.8px. A 10mm margin is about 118px.
Is it better not to turn text into an image?
Yes. Documents with a lot of text come out cleaner as a PDF than as an image.
When the text on a poster or flyer is turned into an image, its edges can blur even at 300dpi. The smaller the text, the more it shows.
Word, PowerPoint and Canva can all export to PDF. In a PDF, text stays as text.
How do you set the A4 pixel count in each app?
Where you set the A4 pixel count depends on the app. The settings, checked against each app's help pages, are shown in the table below.
| App | Where to set A4 | How pixels and resolution are handled |
|---|---|---|
| Word | Page Setup > Paper > Paper size, choose A4 | Pasted pictures are compressed to 220ppi by default. You can change this under File > Options > Advanced > Image Size and Quality |
| Excel | Page Layout > Scale to Fit, set Width and Height to "1 page" | There is no pixel setting. Fitting to one page shrinks the text by the scaling ratio |
| PowerPoint | Design > Slide Size > Custom Slide Size, choose A4 | Saving as an image uses 96dpi by default. On Windows, the ExportBitmapResolution registry value can raise it to 300 |
| Canva | When creating a design, choose "A4 Document" or "Custom size" in mm | Exporting as "PDF Print" lets you add bleed and crop marks |
| Photoshop | File > New, set Width and Height in millimeters and Resolution to 300 Pixels/Inch | In Image Size, turning off Resample changes only the ppi without changing the pixel count |
Of the items in the table, these three are the easiest to overlook.
Why do pictures pasted into Word get blurry?
Because Word compresses pasted pictures to 220ppi by default.
Microsoft Support explains it as follows:
- "The default image resolution in Microsoft 365 is 220 ppi"
- It also explains how to change the default resolution and how to turn off compression
If you are sending a photo-heavy A4 document to a print shop, turn this setting off first.
Is PowerPoint's "A4" the real A4 size?
No. PowerPoint's "A4" does not have the proportions of real A4.
The table on Microsoft Support gives these dimensions:
- A4 slide: 27.517cm wide × 19.05cm high (wider than real A4)
When printed, it is fitted to the page with "Scale to Fit Paper."
Also, when you save a slide as an image, the default resolution is 96dpi. That is not enough for A4 at 300dpi. When you need a higher resolution, do one of the following:
- Export as PDF
- On Windows, change the registry value (ExportBitmapResolution)
What does "Resample" change in Photoshop?
"Resample" is the checkbox that decides whether the pixel count changes.
- Off: the pixel count stays the same. Only the ppi and the print size change
- On: pixels are added or removed
Adobe's help also explains that enlarging cannot add detail that was not in the original image.
Is a smartphone photo's pixel count enough for A4?
A photo of 12 million pixels or more can fill A4 at 300dpi. The part that does not fit the aspect ratio is cropped off.
The pixel count needed to fill A4 is as follows:
- 300dpi: 2480 × 3508 = about 8.7 million pixels
- 350dpi: 2894 × 4093 = about 11.8 million pixels
Canon's print lessons also put the pixel count needed for A4 at about 9 million pixels.
| Photo pixel count (example) | Approx. pixel dimensions at 4:3 | A4 300dpi (about 8.7 million pixels) | A4 350dpi (about 11.8 million pixels) |
|---|---|---|---|
| 12 million pixels (iPhone 12 Pro Max, etc.) | about 4000 × 3000 | Enough | Almost enough (slightly short after cropping) |
| 24 million pixels (iPhone 15 default) | about 5700 × 4300 | More than enough | Enough |
| 48 million pixels (iPhone 15 maximum) | about 8000 × 6000 | More than enough | More than enough |
| 50 million pixels (Pixel 9 wide camera) | about 8200 × 6100 | More than enough | More than enough |
"Enough" in the table means this: even after cropping part of the photo to fit the A4 ratio, you can keep 300dpi.
Suppose you use a 12-million-pixel photo across the full long side. That gives about 340dpi on the long side of A4 (4000 ÷ 11.69 inches). On the short side, the part that does not fit the ratio is cropped.
However, even with enough pixels, image quality drops in these three cases:
- Shot zoomed in (digital zoom): many pixels, but no fine detail
- Shot in a dark place: noise increases and stands out in print
- Sent through a messaging app: it was downscaled when sent
Here is the key point. For printing, get the original file you shot, by cable or from the cloud. Photos received through a messaging app are often too small for A4.
What are the common mistakes with A4 pixel counts?
The most common one is "making it at 72dpi and sending it to print." The mistakes people most often ask about are shown in the table below.
| Mistake | What happens | How to fix it |
|---|---|---|
| Making it at 72dpi and sending it to print | Looks sharp on screen but blurry in print. It has only about a quarter of the dots of 300dpi | Make it at 300dpi or higher dimensions from the start |
| "Converting" a small image to 300dpi | The pixel count goes up, but the detail does not | Find the larger original image. If there is none, use it at a smaller size |
| Making it in portrait and printing in landscape | It gets shrunk, or margins are added | Decide the orientation before making the data |
| Forgetting the bleed | White edges appear when the cutting is slightly off | Make it at a size that adds the bleed width your print shop specifies |
| Assuming PowerPoint's "A4" is A4 | The proportions differ, so margins appear at the top and bottom in print | Export as PDF and fit it to the paper when printing |
| Photos pasted into Word turn blurry | The default 220ppi compression is applied | Turn off compression before pasting |
| Memorizing the pixel count as one number | A different dpi gives a different number | Remember it "as a pair with the dpi" |
A 72dpi image looks fine on screen, so the problem is easy to miss. You only notice once it is printed.
You can prevent this by comparing the image's width in pixels with px (300dpi) in the table before sending it to print.
What terms come up with A4 pixel counts?
| Term | Meaning | Source |
|---|---|---|
| Pixel (px) | One of the dots that make up an image. Image size is expressed as the number of dots across and down | Adobe Help |
| dpi | Dots per inch. The number of dots per inch. The density of a printer or of printing | Canon's glossary |
| ppi | Pixels per inch. The number of pixels per inch. The density of image data | Adobe Help |
| Resolution | Fineness expressed in dpi or ppi. Sometimes also used to mean an image's total pixel count | Adobe Help |
| Inch | A unit of length. 1 inch = 25.4mm. Defined as 96px in CSS | CSS Values and Units Module Level 3 |
| Point (pt) | A unit of type size. 1pt = 1/72 inch | CSS Values and Units Module Level 3 |
| Bleed | Artwork extended beyond the finished size, as a margin for error in cutting | Your print shop's specifications |
| Crop marks | Marks showing where to cut. Also called trim marks (tombo in Japanese) | Canva's guide |
| Resample | Changing an image's size by adding or removing pixels | Adobe Help |
| A series | The series of paper sizes set by ISO 216 and JIS P 0138. The ratio is 1 : √2 | ISO 216 |
What else should you know along with A4 pixel counts?
Does a PDF itself have an A4 pixel count?
No. A PDF or Word document itself has no pixel count.
Text and shapes are stored as dimensions. The printer turns them into dots when printing.
Pixel count only matters for the photos and images placed inside. Export the document as PDF. Only the placed images need to meet the 300dpi dimensions.
How do you decide the dpi for scanning?
Decide the scanning dpi separately from the printing dpi. The guideline is 200 to 350dpi.
Suppose you scan a paper document and print it again on A4. The scanning dpi directly sets the pixel count of the image.
Canon's glossary gives 200 to 350dpi as the guideline for scanning. Scanning A4 at 300dpi gives the same numbers as px (300dpi) in the table.
Is a higher dpi always better?
No. For photos, staying at 300 to 350dpi is easier to work with.
Making it at 600dpi gives a file four times the size of 300dpi. In photos, differences above 300dpi are hard to see.
What you notice first are the inconveniences: files too large to email and software that slows down. Use 600dpi only for line art and small text.
A4 pixel count: frequently asked questions
How many pixels is A4?
It depends on the dpi. At 300dpi, the standard for printing, it is the px (300dpi) value in the table above.
At 72dpi for screens, it is the px (72dpi) value. Decide the use first, then check with the table or the calculator.
How does the A4 pixel count change between portrait and landscape?
Only the width and height swap. The total number of pixels stays the same.
The values in the table are for portrait, so for landscape, swap the width and height.
Can I print an image made at 72dpi if I change it to 300dpi?
No. Changing the number alone does not add detail.
Even if you turn on "Resample" and add pixels, you just get more dots and it stays blurry. Either prepare a larger original image or use it at a smaller size.
Can smartphone photos be printed on A4?
Yes. With 12 million pixels or more, a photo can fill A4 at 300dpi.
However, the aspect ratio differs, so part of it is cropped. Photos taken with digital zoom or in dark places look rough even with plenty of pixels.
When sending to a print shop, should I use 300dpi or 350dpi?
Follow the print shop's specification. If there is none, 300dpi is enough.
Canon's print lessons give 300 to 350ppi. Epson's FAQ gives 300 to 360dpi.
Is bleed always necessary?
No. You need it only when color or photos run to the edge of the paper.
If the design has a white margin all around, you can make it at the finished size alone. For the width, follow your print shop's specification.
Sources
- ISO 216:2007 Writing paper and certain classes of printed matter. Trimmed sizes. A and B series (ISO)
- JIS P 0138 Trimmed sizes of processed paper (Japanese Industrial Standards Committee, JIS search)
- CSS Values and Units Module Level 3: Absolute lengths (W3C)
- dpi: Photography glossary (Canon)
- Print lessons that will change your photos, Lesson 3: Pixel count and resolution (Canon)
- Printing and scanning images: What is the recommended resolution for output print size? (Epson UK FAQ KA-01467)
- Photoshop: Image size and resolution (Adobe)
- Change the paper size (Microsoft Support)
- Change the margins (Microsoft Support)
- Reduce the file size of a picture in Microsoft Office (Microsoft Support)
- Scale a worksheet (Microsoft Support)
- Change the size of your PowerPoint slides (Microsoft Support)
- How to export high-resolution (high-dpi) slides from PowerPoint (Microsoft Learn)
- PDF Print (Canva)
- iPhone 15 technical specifications (Apple)
- iPhone 12 Pro Max technical specifications (Apple)
- Google Pixel 9 tech specs (Google Store)