My mobile phones (Sony Xperia C5, OPPO R11 Plus) are both 122.6 PPI,Īpple iPhone 5 is 163 PPI, iPhone 7 is 162 PPI, iPhone X is 151.7 PPI. Now i have the most accurate virtual ruler on the web. So i adjust the default pixels per inch(PPI) to 100.7, I found the markings are not very accurate at 30cm, In the office, a A4 size printable paper is a good comparison object,īelow ruler adjuster help us to calibrate accuracy more easily.Īfter i measure the size of virtual ruler by an actual ruler, You can compare to any standard size object at your side,Į.g., coin, credit card, CD, paper money, mobile phone,

When you know the width, you can adjust the ruler's PPI setting by it, Then search 'the width of your paper money' online,

Use standard objects to compare lengths, check your wallet, use any paper money to be our compare object,.

I am lucky and found my screen has 100 PPI.

Search 'display by pixel density' online, check if there has your device's brand and model,.

The screen resolution of your current device is pixels. To have the most accurate ruler online, just set the pixels per inch(PPI),īelow are some ways to know the pixels per inch to your device.

Free ruler image inches