Handy & Accurate Online Ruler
This is a convenient online ruler that could be calibrated to actual size, measurements in cm, mm and inch, the upper half is the millimeter ruler and centimeter ruler, the lower half is an inch ruler. In order to accurately measure the length of your item, we strongly recommend that you calibrate this online ruler first, set the correct pixels per inch to your own device, after adjustment, you will have the most precise ruler online. It can talk 🙊
How to adjusting this virtual ruler to actual size
- My laptop has a wide screen (13.6"x7.6"), and resolution is 1366x768 pixels, 1366 / 13.6 = 100.44 PPI. The screen resolution of your current device is pixels.
- Search "display by pixel density" online, check if there has your device's brand and model, i am lucky and found my screen has 100 PPI.
- Use standard objects to compare lengths, check your wallet, use any paper money to be our compare object, then search "the width of your paper money" online, when you know the width, you can adjust the ruler's PPI setting by it, you can compare to any standard size object at your side, e.g., coin, credit card, CD, paper money, mobile phone, in the office, a A4 size printable paper is a good comparison object, the longer the more accurate. Below ruler adjuster help us to calibrate accuracy more easily.
- The most accurate way, after i measure the size of virtual ruler by an actual ruler, i found the markings are not very accurate at 30cm, so i adjust the default pixels per inch(PPI) to 100.7, now i have the most accurate virtual ruler on the web.
- Each device has it's own PPI, eg. my Asus laptop is 100.7 PPI, Apple MacBook Air is 127.7 PPI, Xiaomi Mi Pad 3 is 163 PPI, my mobile phones (Sony Xperia C5, OPPO R11 Plus) are both 122.6 PPI, Apple iPhone 5 is 163 PPI, iPhone 7 is 162 PPI, iPhone X is 151.7 PPI.
How to use your computer screen as a ruler?
All you need is a web browser and a credit card to compare physical sizes, no installation required, free to use, and works on your phone screen as well.
Compare ruler with credit card
Dragging ruler adjuster left or right to fit the size of your reference object, remember to save the setting for the next time you use it, after save the setting, refresh your brower to check the result. On the most popular browsers you can press the F5 key or click on the refresh button.
Translate into your native language
This online ruler is free to use,
and we want to provide a better native language environment,
make it more natural and easier for everyone to use,
if you are willing to offer a better description in your native language,
benefit your fellow countrymen,
please visit this translation page(click).
Below are some other language version.
The story of our ruler
One day, i took my laptop computer to work in the coffee shop, just had a project on hand, and i had to tell the customer the actual size of a product. Just like usual, i didn't carry a ruler with me, so i connected to the internet and tried to find an online virtual ruler to measure my product.
Unfortunately, after i tried the virtual online rulers on the Internet, i found a problem that these existing online rules are not very accurate. If i just want to know what the approximate length is, that's fine, but what i need is a more precise length so that i can apply it to my daily work.
So later, we developed an online ruler by ourselves. It not only improves the accuracy of the measurement, but also has a scale of inches and centimeters so that it can be used in our work.
If you are like us, you need a precise online ruler to measure the product size, i believe this online virtual ruler can also meet your needs.
Red vertical line
Clicking on the ruler will mark a red vertical line for easy comparison of metric and imperial lengths.
How to read a ruler
Move your mouse cursor over the ruler and it will show the length, if you touch or click on it, it will talk to you, if you don't know how to read the ruler, try clicking on it, click in different places, it will tell you the length, it's kind of interesting.
Command function
I am very happy that many people like our online ruler,
also i am very excited to review all the comments from all the visitors.
Regarding the joke about comments or commands here,
i decided to add a new "command" function(on the page top) for our dear friends,
In addirion to showing the length, I also addewd a comparison command,
I try to make the AI interaction smarter,
hope you like our new command function 😛,
welcome to try it and share it, let me know your idea.
show 12 mm, show 2.3 cm, show me 5 2/3 in, show me 6.4 inches, show me how long 1 inch is, show 1 ft ...etc.
compare 4 in and 10 cm, compare 12.5 cm and 1 3/4 in
Browser zoom level
The zoom ratio of current page is 100%, we recommend using a fixed zoom ratio of 100%, different zoom ratios will affect the accuracy of the ruler, please compare the physical item and calibrate the setting by yourself.
Changing the system font size on the phone will affect the layout of the web page, just use the pinch gesture to bring your fingers together to reduce the page size, zoom out to the minimum and you can see the full size ruler.
Our Facebook pages
What do you think about this online ruler ?
Use this screen ruler on your smartphone
Scan above QR code to open browser, and turn your mobile phone screen to landscape mode, so that the length of online ruler will longer.
If the dynamic ruler doesn't redraw after you rotate the smartphone, please ↻refresh your browser
Online rulers
- Actual size online ruler : the most accurate size ruler on the web.
- Vertical virtual ruler : measure items in a vertical direction.
- Virtual ruler on your image : practice how to use a ruler.
- Metric scale ruler : variable scale ruler with metric units(cm, m, km)
- Imperial scale ruler : variable scale ruler with imperial units(in, ft, yd, mi)
- Online protractor : use this transparent protractor to measure the angle of anything
- What is my screen size : use credit card comparison to calculate real screen size
When you need to measure the length of something, is it always impossible to find a ruler, our digital online ruler can help you, support both metric and imperial units, it can be calibrated quickly and the measurement is very accurate.
Share to your good friends
Length Unit Converters
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Convert MM/CM to Inches :
convert mm to inches, cm to inches, inches to cm/mm,
include convert decimal inch to fractional inch (e.g. 1.45" = 1 7/16").
Where is 1.8" in on a 12" ruler ? Where is the 3.2 cm in the 12 inches ruler ? Try this cm inch converter. - Converter Meters to Feet : convert meters, feet and inches (m, ft and in), convert each other.
- Convert Yards to Meters : yards & meter converter, convert yards to meters, or meters to yards.
- Convert CM to MM : convert millimetre/millimeter(mm) to centimetre/centimeter(cm), or reverse convert.
How to use a ruler
This ruler measure in two different units of length, inches on one side (English ruler) and centimeters on the other side (metric ruler). A metric ruler is use to measure centimeter(cm) and millimeter(mm), the centimeter is a unit of length in the International System of Units; An English ruler provides incremental measurements in inches, with each inch further divided into smaller fractions.
Read an English ruler using fractions of an inch. The distance between any two large numbered lines is 1 inch. The large unnumbered line that is halfway between them is 1/2 inch. The smaller (but still prominent) line between the 1/2 mark and the numbered inch line is 1/4 inch. The tiny little lines between all of the more prominent lines are 1/16 inch.
Observe the much simpler metric rulers. The distance between any two large numbered lines is 1 cm, a metric ruler features two types of lines. The largest mark centimeters, or cm. The smallest lines mark millimeters, or mm. The prominent line between any two numbered lines is 1/2 cm. The small lines between the 1/2 mark and the numbered centimeter mark are 1/10 cm, otherwise known as a millimeter, keep in mind that there are 10 mm to 1 cm. The measurements are decimalized and there are no fractions.
Record distances by the name of the line that it most closely matches. If the length of an object goes to one mark past the halfway mark on your ruler then it will be 9/16 inch on an English ruler or 6/10 cm (or 6 mm) on a metric ruler.