Bootstrap row class contains margin-left and margin-right which creates problems

The .row is meant to be used inside a container. Since the container has padding to adjust the negative margin in the .row, grid columns used inside the .row can then adjust to the full width of the container. See the Bootstrap docs: http://getbootstrap.com/css/#grid

Here's an example to illustrate: https://codeply.com/p/zHFaC7JR5K

So, a better solution may for you to place your .row inside a .container or .container-fluid

You can use row-fluid instead of row, then you won't have this problem. (for previous versions of bootstrap)

I am not sure of recent versions 3, any way :

The issue is that the first column should not have half a gutter on the left, and the last should not have half a gutter on the right. Rather than use some sort of .first or .last class on those columns as some grid systems do, they instead set the .row class to have negative margins that match the padding of the columns. This "pulls" the gutters off of the first and last columns, while at the same time making it wider.

For more information on this Why does the bootstrap .row has a default margin-left of -30px?

Are you using Bootstrap 3? My version of the css has -15px, not -13px. In any case, I've simply done what you've down, and overwritten the style. I believe it's because the .container class has a 15px padding on the left and right, and this negative margin on the rows will pull that content back out to the edge of the container.

Old topic, but I think I found another descent solution. Adding class="row" to a div will result in this CSS configuration:

.row {
    display: -webkit-box;
    display: flex;
    flex-wrap: wrap;
    margin-right: -15px;
    margin-left: -15px;
}

We want to keep the first 3 rules and we can do this with class="d-flex flex-wrap" (see https://getbootstrap.com/docs/4.1/utilities/flex/):

.flex-wrap {
    flex-wrap: wrap !important;
}
.d-flex {
    display: -webkit-box !important;
    display: flex !important;
}

It adds !important rules though but it shouldn't be a problem in most cases...

Here is your simple and easy answer

Go to your class where you want to give a negative margin then copy and paste this inside the class.

Example for negative margin top

mt-n3

Example for negative margin bottom

mb-n2