Pixels per millimeter to Pixels per inch Converter
Quick answer: To convert pixels per millimeter to pixels per inch, multiply by 25.4. For example, 10 px/mm is 254 ppi. One pixel per millimeter equals 25.4 ppi.
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Use the Pixels per millimeter to Pixels per inch Converter
Pixels per millimeter to Pixels per inch formula and what each symbol means
ppi = px/mm × 25.4
| Symbol | Meaning |
|---|---|
| px/mm | Pixel per millimeter |
| ppi | Pixel per inch |
Pixels per millimeter to Pixels per inch examples
1 px/mm
1 px/mm × 25.4 = 25.4 ppi.
10 px/mm
10 px/mm × 25.4 = 254 ppi.
100 px/mm
100 px/mm × 25.4 = 2,540 ppi.
Pixels per millimeter compared with Pixels per inch
One px/mm is 25.4 times as large as one ppi, so your number gets bigger when you convert pixels per millimeter to pixels per inch and smaller when you convert back. If the answer is not larger than what you typed, you divided instead of multiplying.
About pixels per millimeter and pixels per inch
Pixel per millimeter (px/mm): Pixels per millimetre, 25.4 ppi. Pixel per inch (ppi): Pixels per inch.
How to calculate Pixels per millimeter to Pixels per inch step by step
- Enter the value in px/mm (the starting unit).
- Multiply by 25.4, because 1 px/mm = 25.4 ppi.
- The product is the value in ppi. To go back, divide by 25.4 or multiply by 0.03937008.
Popular digital image resolution conversions
How to read your Pixels per millimeter to Pixels per inch result
Quick estimate: multiply by about 25 to get pixels per inch from pixels per millimeter; this is within 1.6% of the exact factor. Image resolution is how many pixels fit in a unit of length.
| PIXELS PER MILLIMETER | PIXELS PER INCH |
|---|---|
| 1 | 25.4 |
| 2 | 50.8 |
| 5 | 127 |
| 10 | 254 |
| 20 | 508 |
| 50 | 1,270 |
| 100 | 2,540 |
| 1,000 | 25,400 |
Pixels per inch to Pixels per millimeter: quick table
| PIXELS PER INCH | PIXELS PER MILLIMETER |
|---|---|
| 1 | 0.03937008 |
| 5 | 0.1968504 |
| 10 | 0.3937008 |
| 25 | 0.984252 |
| 50 | 1.968504 |
| 100 | 3.937008 |
| 250 | 9.84252 |
| 500 | 19.68504 |
Common mistakes when calculating Pixels per millimeter to Pixels per inch
- Assuming ppi changes the pixel dimensions of an image; it changes only the print size.
- Dividing when you should multiply: from px/mm to ppi multiply by 25.4; from ppi to px/mm divide by 25.4.
Pixels per millimeter to Pixels per inch FAQ
How many ppi are in 1 px/mm?
1 px/mm equals 25.4 ppi.
How many px/mm are in 1 ppi?
1 ppi equals 0.03937008 px/mm.
Is 1 px/mm = 25.4 ppi an exact conversion?
The factor is shown rounded to 7 significant figures (25.4). The calculator above uses more digits.
What is a pixel per millimeter (px/mm)?
Pixels per millimetre, 25.4 ppi.
How can I estimate pixels per millimeter to pixels per inch in my head?
Quick estimate: multiply by about 25 to get pixels per inch from pixels per millimeter; this is within 1.6% of the exact factor.
What is 7 px/mm in pixels per inch?
7 px/mm = 177.8 ppi (since 7 × 25.4).
What is 40 px/mm in pixels per inch?
40 px/mm = 1,016 ppi (since 40 × 25.4).
What is 200 px/mm in pixels per inch?
200 px/mm = 5,080 ppi (since 200 × 25.4).
How many decimals should I keep when converting px/mm to ppi?
Match the precision of your original measurement. For example, 254 ppi rounds to 254 ppi at 3 significant figures; keep more digits only for engineering or scientific work.
Method, review and disclaimer
Edited by: Hemant Kumar and Anjita Rai, founders of ToolsVault (SEO and content professional, not a licensed adviser). Method: this tool runs in your browser using the formula shown on this page; the numbers you enter are not sent to our servers. Sources: NIST SP 811, Appendix B.8: conversion factors, BIPM: the International System of Units (SI)