Pixels per inch to Pixels per millimeter Converter
Quick answer: To convert pixels per inch to pixels per millimeter, multiply by 0.03937008. For example, 10 ppi is 0.3937008 px/mm. One pixel per inch equals 0.03937008 px/mm.
- Calculator
- Formula
- Examples
- Size compared
- About the units
- Step by step
- Popular conversions
- Reading your result
- Mistakes
- FAQ
- Related tools
- Method
Use the Pixels per inch to Pixels per millimeter Converter
Pixels per inch to Pixels per millimeter formula and what each symbol means
px/mm = ppi × 0.03937008
| Symbol | Meaning |
|---|---|
| ppi | Pixel per inch |
| px/mm | Pixel per millimeter |
Pixels per inch to Pixels per millimeter examples
1 ppi
1 ppi × 0.03937008 = 0.03937008 px/mm.
10 ppi
10 ppi × 0.03937008 = 0.3937008 px/mm.
100 ppi
100 ppi × 0.03937008 = 3.937008 px/mm.
Pixels per inch compared with Pixels per millimeter
One px/mm is 25.4 times as large as one ppi, so your number gets smaller when you convert pixels per inch to pixels per millimeter and bigger when you convert back. If the answer is not smaller than what you typed, you multiplied instead of dividing.
About pixels per inch and pixels per millimeter
Pixel per inch (ppi): Pixels per inch. Pixel per millimeter (px/mm): Pixels per millimetre, 25.4 ppi.
How to calculate Pixels per inch to Pixels per millimeter step by step
- Enter the value in ppi (the starting unit).
- Multiply by 0.03937008, because 1 ppi = 0.03937008 px/mm.
- The product is the value in px/mm. To go back, divide by 0.03937008 or multiply by 25.4.
Popular digital image resolution conversions
How to read your Pixels per inch to Pixels per millimeter result
Quick estimate: multiply by about 0.04 to get pixels per millimeter from pixels per inch; this is within 1.6% of the exact factor. Photo prints commonly aim for about 300 ppi, while screens usually run from about 72 to 400 ppi.
| PIXELS PER INCH | PIXELS PER MILLIMETER |
|---|---|
| 1 | 0.03937008 |
| 2 | 0.07874016 |
| 5 | 0.1968504 |
| 10 | 0.3937008 |
| 20 | 0.7874016 |
| 50 | 1.968504 |
| 100 | 3.937008 |
| 1,000 | 39.37008 |
Pixels per millimeter to Pixels per inch: quick table
| PIXELS PER MILLIMETER | PIXELS PER INCH |
|---|---|
| 1 | 25.4 |
| 5 | 127 |
| 10 | 254 |
| 25 | 635 |
| 50 | 1,270 |
| 100 | 2,540 |
| 250 | 6,350 |
| 500 | 12,700 |
Common mistakes when calculating Pixels per inch to Pixels per millimeter
- Assuming ppi changes the pixel dimensions of an image; it changes only the print size.
- Dividing when you should multiply: from ppi to px/mm multiply by 0.03937008; from px/mm to ppi divide by 0.03937008.
Pixels per inch to Pixels per millimeter FAQ
How many px/mm are in 1 ppi?
1 ppi equals 0.03937008 px/mm.
How many ppi are in 1 px/mm?
1 px/mm equals 25.4 ppi.
Is 1 ppi = 0.03937008 px/mm an exact conversion?
The factor is shown rounded to 7 significant figures (0.03937008). The calculator above uses more digits.
What is a pixel per inch (ppi)?
Pixels per inch.
How can I estimate pixels per inch to pixels per millimeter in my head?
Quick estimate: multiply by about 0.04 to get pixels per millimeter from pixels per inch; this is within 1.6% of the exact factor.
What is 300 ppi in pixels per millimeter?
300 ppi = 11.81102 px/mm (since 300 × 0.03937008).
What is 12 ppi in pixels per millimeter?
12 ppi = 0.4724409 px/mm (since 12 × 0.03937008).
What is 60 ppi in pixels per millimeter?
60 ppi = 2.362205 px/mm (since 60 × 0.03937008).
How many decimals should I keep when converting ppi to px/mm?
Match the precision of your original measurement. For example, 0.3937008 px/mm rounds to 0.394 px/mm 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)