Pixels to Inches and CM Converter with DPI Calculator
Enter a print size or a photo size in pixels and get pixels, inches, centimeters, megapixels and an estimated file size right away. Free, no signup, everything is calculated in your browser.
Print sizes in pixels: chart for 300 and 150 DPI
How many pixels each print size needs. Use the 300 DPI column for photos viewed up close; 150 DPI is enough for a poster on the wall.
| Print size | Dimensions | Pixels at 300 DPI | Pixels at 150 DPI |
|---|---|---|---|
| Photo prints | |||
| 4×6 in | 101.6 × 152.4 mm | 1200 × 1800 px | 600 × 900 px |
| 5×7 in | 127 × 177.8 mm | 1500 × 2100 px | 750 × 1050 px |
| 8×10 in | 203.2 × 254 mm | 2400 × 3000 px | 1200 × 1500 px |
| 10×15 cm | 100 × 150 mm | 1181 × 1772 px | 591 × 886 px |
| 13×18 cm | 130 × 180 mm | 1535 × 2126 px | 768 × 1063 px |
| 20×30 cm | 200 × 300 mm | 2362 × 3543 px | 1181 × 1772 px |
| Paper | |||
| Letter | 215.9 × 279.4 mm | 2550 × 3300 px | 1275 × 1650 px |
| A5 | 148 × 210 mm | 1748 × 2480 px | 874 × 1240 px |
| A4 | 210 × 297 mm | 2480 × 3508 px | 1240 × 1754 px |
| A3 | 297 × 420 mm | 3508 × 4961 px | 1754 × 2480 px |
| ID photos | |||
| 2×2 in | 50.8 × 50.8 mm | 600 × 600 px | 300 × 300 px |
| 3.5×4.5 cm | 35 × 45 mm | 413 × 531 px | 207 × 266 px |
Values are rounded to whole pixels. A 4x6 print is not the same shape as most phone photos (4:3), so expect some cropping.
How to convert pixels to inches and centimeters
DPI tells you how many pixels land on one inch of paper, and one inch is 2.54 cm. That gives two formulas: pixels = inches × DPI, and inches = pixels ÷ DPI. For centimeters, multiply the inches by 2.54. A 6 inch side at 300 DPI is 6 × 300 = 1800 pixels.
How many pixels is 4x6 at 300 DPI
A 4x6 inch print at 300 DPI is 1200 × 1800 px, about 2.2 MP. At 150 DPI you need 600 × 900 px, but the print will look softer up close.
Pixels for 5x7 and 8x10 prints
At 300 DPI a 5x7 print needs 1500 × 2100 px and an 8x10 needs 2400 × 3000 px, which is 7.2 MP.
Px to cm at common resolutions
At 300 DPI there are about 118 pixels in a centimeter, at 150 DPI 59, at 96 DPI 38 and at 72 DPI 28. A 3000 × 2000 px image at 300 DPI measures 25.4 × 16.93 cm, or 10 × 6.67 in.
What DPI and PPI mean
PPI (pixels per inch) is the number of image pixels per inch of a print or a screen. DPI (dots per inch) is the number of ink dots a printer places per inch of paper. In everyday use the two words mean the same thing: how densely your pixels are packed on paper. Higher density means finer detail and a smaller print from the same file.
Why 72 DPI for screens is a myth
A screen shows an image pixel for pixel and ignores the DPI value stored in the file. A 1920 × 1080 photo takes up the same space on a monitor whether it is tagged 72 or 300 DPI. The number 72 comes from the first Macintosh computers, whose displays had 72 pixels per inch. For websites and social media, only the pixel dimensions matter.
What resolution you need for printing
300 DPI is the standard for photos held in the hand. 200 DPI is fine for an album or a framed photo on a desk. 150 DPI works for posters viewed from a few feet away. Below 150 DPI the pixels start to show.
How many megapixels you need for a print
Megapixels are the width in pixels times the height, divided by one million. To find out how many a print needs, convert its size to pixels at 300 DPI.
Megapixels for Letter and A4
A Letter page at 300 DPI is 2550 × 3300 px, or 8.4 MP. A4 is 2480 × 3508 px, or 8.7 MP; at 150 DPI 1240 × 1754 px is enough. A 12 MP photo (4000 × 3000 px) prints at 13.33 × 10 in at 300 DPI, which is larger than either page.
Megapixels for A3 and small prints
A3 at 300 DPI takes 3508 × 4961 px, or 17.4 MP, while 4.3 MP is enough at 150 DPI. A 4x6 print needs only 2.2 MP, well within reach of any modern phone.
How to find the pixel size of a photo
The quickest way is the "From a photo file" tab: drop the image in and the calculator shows its dimensions and how large it can be printed. You can also look in the file properties.
On a computer
Windows: right-click the file, choose Properties and open the Details tab. Mac: select the file in Finder and press Command+I, or open it in Preview and choose Tools, then Show Inspector.
On a phone
iPhone: open the picture in Photos and swipe up or tap the info button. Android: in Google Photos swipe up on the picture or open the three-dot menu; the dimensions are listed in the details.
How big a photo file is
File size depends on the pixel count and the compression. Uncompressed, each pixel takes 3 bytes, so a 12 MP frame is about 34 MB. JPEG brings that down to 2 to 6 MB: a plain sky compresses well, foliage and fine texture do not. The calculator shows a range for normal JPEG quality.
Frequently asked questions
How many pixels are in an inch?
It depends on the DPI: at 300 DPI there are 300 pixels in an inch, at 150 DPI 150, at 96 DPI 96. To get pixels per centimeter, divide the DPI by 2.54.
What resolution do I need to print an 8x10?
For a sharp print at 300 DPI you need 2400 × 3000 px. The practical minimum at 150 DPI is 1200 × 1500 px.
How many pixels is a 2x2 inch passport photo?
At 300 DPI a 2x2 inch photo is 600 × 600 px. If the photo is for a document, check the official rules too: head size, background and file size often matter as well.
Can I change 72 DPI to 300 in the file to make the photo better?
No. The DPI value is only a tag in the metadata and does not add pixels. The print size at 300 DPI depends on the pixel count alone. If there are not enough pixels, the photo has to be upscaled.
How large can I print a phone photo?
A 12 MP shot (4000 × 3000 px) prints in excellent quality up to 13.33 × 10 in, and up to 26.67 × 20 in at 150 DPI. A 48 MP shot (8000 × 6000 px) reaches 26.67 × 20 in at 300 DPI.
How big is a 4x6 photo file at 300 DPI?
It holds about 2.2 MP. As a JPEG it usually weighs 0.4 to 1 MB, and about 6 MB uncompressed.
Is my photo uploaded to a server?
No. The calculations and the reading of the photo dimensions happen in your browser, and the file is not sent anywhere. The calculator is free and needs no signup.
Read also
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