Pixel Converter
Work out how big a pixel measurement is on paper, how many pixels a printed size needs, or how many KB fit in a megabyte. Type a number, choose the units and the DPI, and the answer appears as you type, with no file to upload.
Unit Converter
Nothing is uploaded; the code is generated for you to download.
Pixels per inch used to turn pixels into cm, mm or inches. 96 is the screen/CSS standard; use 300 for photos and print, or the DPI a form specifies. At 300 DPI, 1 cm = 118 px.
Windows and most upload forms count 1 KB = 1024 bytes (1 MB = 1024 KB). macOS and disk makers use 1000. The difference is about 5% at MB size.
How many digits to show after the decimal point in the result.
Also shows the matching other side at this ratio, e.g. 1920 px wide at 16:9 is 1080 px tall.
First number of the ratio, e.g. 5 for 5:7.
Second number of the ratio, e.g. 7 for 5:7.
How to use this tool
- 1
Enter a value and units
Type the number in Value, then pick From and To. Lengths (px, pt, mm, cm, in) convert among themselves, and file sizes (B, KB, MB, GB, TB) convert among themselves.
- 2
Set the conversion basis
Open Advanced settings. For lengths, set Pixel density: 96 for screens and CSS, 300 for print, or the DPI a form names. For file sizes, choose whether 1 KB equals 1024 or 1000 bytes. Decimal places sets the rounding.
- 3
Read the matching size
The result updates instantly. Pick a ratio in Keep aspect ratio, such as 16:9 or 4:5, to see the other side of the image too, or choose Custom and enter your own two numbers.
Pixels to cm, inches, mm and points at 96 DPI
| Pixels | Centimeters | Inches | Millimeters | Points |
|---|---|---|---|---|
| 1 px | 0.03 cm | 0.01 in | 0.26 mm | 0.75 pt |
| 16 px (default body text) | 0.42 cm | 0.17 in | 4.23 mm | 12 pt |
| 100 px | 2.65 cm | 1.04 in | 26.46 mm | 75 pt |
| 300 px | 7.94 cm | 3.13 in | 79.38 mm | 225 pt |
| 600 px | 15.88 cm | 6.25 in | 158.75 mm | 450 pt |
| 1080 px | 28.58 cm | 11.25 in | 285.75 mm | 810 pt |
| 1920 px | 50.80 cm | 20 in | 508 mm | 1440 pt |
| in | Pixels at | ||
|---|---|---|---|
| 72 DPI | 150 DPI | 300 DPI | |
| 1 | 72 | 150 | 300 |
| 2 (US passport photo) | 144 | 300 | 600 |
| 4 × 6 print, short side | 288 | 600 | 1200 |
| 5 | 360 | 750 | 1500 |
| 8.5 (Letter width) | 612 | 1275 | 2550 |
| 11 (Letter height) | 792 | 1650 | 3300 |
The inch has been exactly 2.54 cm since the international yard and pound agreement of 1959, so the only uncertain number in any pixel conversion is the density. CSS fixes it at 96: the specification defines 1 in as 96 px, which is why a stylesheet's 1 cm is always 37.8 px even on a 4K monitor. Print uses whatever the printer or form demands, most often 300 for photos and 150 for drafts, and the 72 column still matters because many export dialogs and old files default to it.
Pixel density accepts anything from 1 to 4,800 DPI, which covers phone screens around 460 ppi and high-end scanners. Decimal places goes from 0 to 10: use 0 when you need whole pixels for a resize field, and 2 or more for centimeters. To change the actual pixels of a photo to a printed size, use resize image to cm; for a single quick px ↔ cm lookup, the pixel to cm converter opens with those units already set.
KB to MB, MB to GB and bytes: 1024 or 1000
- KB in 1 GB, binary rule
- 1,048,576
- KB in 1 GB, decimal rule
- 1,000,000
- difference at GB scale
- ≈ 7.4%
- difference at TB scale
- ≈ 10%
Each step up multiplies by 1024 in the binary convention and by 1000 in the decimal one, so the gap grows with every step: 2.4% at KB, about 4.9% at MB, 7.4% at GB and almost 10% at TB. The IEC introduced the names KiB, MiB and GiB in 1998 for the binary values, but Windows File Explorer and most upload checkers still print KB and MB while dividing by 1024.
Choose 1 KB equals 1024 bytes when a Windows program or a government form reports the size, and 1000 bytes for macOS Finder, phone storage screens and drive packaging. The MB to KB converter page is set for exactly that conversion. If the numbers show a file is over a portal limit, shrink it with compress image to 100 KB or the matching target.
Aspect ratios and their pixel sizes
1920 × 1080 px
16:9 (YouTube, TV)
Full HD; 3840 × 2160 for 4K
1080 × 1920 px
9:16 (Reels, Shorts, TikTok)
Vertical full-screen video
1080 × 1350 px
4:5 (Instagram portrait)
Tallest feed post Instagram shows
1080 × 1080 px
1:1 (square)
Profile pictures and square posts
6000 × 4000 px
3:2 (camera photo)
24-megapixel DSLR or mirrorless frame
2560 × 1080 px
21:9 (ultrawide)
Sold as 21:9; the exact ratio is 64:27
Common pixel and file size conversion mistakes
MythA pixel always has the same physical size.
FactIt depends on density. The 96 DPI table above is a screen convention; a printer packs 300 pixels into each inch, so set Pixel density to the print resolution or the print comes out tiny.
MythUpload forms check a photo's size in centimeters.
FactUpload checkers measure pixels. Convert the required cm at the DPI the form names, then resize the photo to that exact pixel size.
MythA file under the stated MB limit is always accepted.
FactYour computer may use the decimal rule while the portal uses 1024, or the reverse. Recalculate with the other 1 KB equals setting and keep a few percent of margin.
MythRaising the DPI in an image editor makes a photo sharper or larger.
FactDPI is only a label stored in the file. The pixel count and KB size stay the same until you resample the image itself.
Pixel converter questions
How many pixels are in an inch?
As many as the DPI says. A screen layout in CSS counts 96 px per inch, a photo printed at photo-lab quality uses 300, and older Mac software assumed 72. That is why the converter asks for Pixel density before it gives an answer.
What is 1920 × 1080 px in centimeters?
At 96 DPI it is 50.8 × 28.58 cm, the size a browser treats it as. Printed at 300 DPI the same image covers only 16.26 × 9.14 cm, roughly a postcard. Change Pixel density to see the size for any other print resolution.
Are points the same as pixels?
Only at 72 DPI. A point is fixed at 1/72 inch, so at the CSS density of 96 DPI one pixel is 0.75 pt and 16 px text equals 12 pt. Word and PDF page sizes are measured in points, so an A4 page is 595 × 842 pt whatever the screen.
How many KB are in 1 GB?
1,048,576 KB when 1 KB is 1024 bytes, the rule Windows uses, or 1,000,000 KB under the decimal rule used by macOS and drive makers. Set 1 KB equals to match the program or form that reports the size.
Why does a 1 TB drive show about 931 GB in Windows?
The maker counts 1 TB as 10¹² bytes, while Windows divides by 1024 three times and still labels the result GB. 10¹² ÷ 1,073,741,824 is 931.3, so nothing is missing; the two numbers are the same capacity in different units.
What DPI should I use for a poster or banner?
300 DPI is the safe value for anything viewed up close, such as flyers and photos. Large posters seen from a few meters are often printed at 150 DPI, and roll-up banners lower still, because nobody stands close enough to see the pixels. Ask the print shop for its minimum before you resize.
How do I find the height for a given width and aspect ratio?
Divide the width by the first number of the ratio and multiply by the second: 1080 px at 4:5 gives 1080 ÷ 4 × 5 = 1350 px. Keep aspect ratio does this for you and shows the result next to the converted value.
All Pixel Converter tools
Pick the exact target you were asked for. Every page below is the same tool with different defaults.