What are the difference between col-lg and col-md in bootstrap3

Question

What are the difference between col-lg, col-md ,col-xs and col-sm grid system in in bootstrap 3.

In a bo

Answer 1

When using Bootstrap those are the classes which are added for one column grid and correspond to extra small, small, medium and large devices.

.col-xs = *Extra small devices (ie Phones) (<768px)

.col-sm = Small devices (ie Tablets) (≥768px)

.col-md = Medium devices (ie laptops, or small desktops) (≥992px)

.col-lg = Large devices (ie Desktops) (≥1200px)*

This way through media queries you can allow to have only the right classes interpreted by the browser. If you surf that website from a tablet for example, you will see that the css properties which are actually applied in the browser are only the ones for the .col-sm class.

UPDATE

Also it's important to mention that those classes are used on a grid of 12 columns in total which is the grid system setup used by Bootstrap.

Therefore when you are using .col-sm-4 on an element it means that the element will take 4 columns out of 12 of the total width. Which logically means that if .col-sm-4 is used then only 3 elements per row can fit into the page on tablet.

For example, let's say we want to show some project cards for a portfolio:

    
  
        
        

            
Project 1
            

                Tech Stack
                
HTML5, CSS, JS
            
       
        
          
    
 
 

Using class="col-xs-12 col-sm-6 col-md-4 col-lg-3" all at the same time is used to activate different CSS properties on an element when viewing the page on a particular device.

In other terms, if the user opens the site on a desktop, col-lg-3 means that a total of 4 cards will be displayed, when col-md-4 means a total of 3 cards, col-sm-6 a total of 2 cards and then col-xs-12 means on mobile only 1 card will with 100% width of the page.