7 equal columns in bootstrap

Well, IMO you probably need to override the width of the columns by using CSS3 @media query.

Here is my attempt to create a 7-col grid system:

<div class="container">
  <div class="row seven-cols">
    <div class="col-md-1">Col 1</div>
    <div class="col-md-1">Col 2</div>
    <div class="col-md-1">Col 3</div>
    <div class="col-md-1">Col 4</div>
    <div class="col-md-1">Col 5</div>
    <div class="col-md-1">Col 6</div>
    <div class="col-md-1">Col 7</div>
  </div>
</div>

@media (min-width: 768px){
  .seven-cols .col-md-1,
  .seven-cols .col-sm-1,
  .seven-cols .col-lg-1  {
    width: 100%;
    *width: 100%;
  }
}

@media (min-width: 992px) {
  .seven-cols .col-md-1,
  .seven-cols .col-sm-1,
  .seven-cols .col-lg-1 {
    width: 14.285714285714285714285714285714%;
    *width: 14.285714285714285714285714285714%;
  }
}

/**
 *  The following is not really needed in this case
 *  Only to demonstrate the usage of @media for large screens
 */    
@media (min-width: 1200px) {
  .seven-cols .col-md-1,
  .seven-cols .col-sm-1,
  .seven-cols .col-lg-1 {
    width: 14.285714285714285714285714285714%;
    *width: 14.285714285714285714285714285714%;
  }
}

The value of width comes from:

width = 100% / 7 column-number = 14.285714285714285714285714285714%

WORKING DEMO – (jsbin)

Run the code snippet and click on the “Full page”.

.col-md-1 {
  background-color: gold;
}

@media (min-width: 768px){
  .seven-cols .col-md-1,
  .seven-cols .col-sm-1,
  .seven-cols .col-lg-1  {
    width: 100%;
    *width: 100%;
  }
}


@media (min-width: 992px) {
  .seven-cols .col-md-1,
  .seven-cols .col-sm-1,
  .seven-cols .col-lg-1 {
    width: 14.285714285714285714285714285714%;
    *width: 14.285714285714285714285714285714%;
  }
}


@media (min-width: 1200px) {
  .seven-cols .col-md-1,
  .seven-cols .col-sm-1,
  .seven-cols .col-lg-1 {
    width: 14.285714285714285714285714285714%;
    *width: 14.285714285714285714285714285714%;
  }
}

<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/css/bootstrap.min.css" rel="stylesheet"/>

<div class="container">
  <div class="row seven-cols">
    <div class="col-md-1">Col 1</div>
    <div class="col-md-1">Col 2</div>
    <div class="col-md-1">Col 3</div>
    <div class="col-md-1">Col 4</div>
    <div class="col-md-1">Col 5</div>
    <div class="col-md-1">Col 6</div>
    <div class="col-md-1">Col 7</div>
  </div>
</div>

Other options

Also, you could build your own 7-columns version of Twitter Bootstrap by using the Custom Builder (Changing the @grid-columns, …).

If you are using less compiler, you could download the less version of Twitter Bootstrap (from Github) and edit the variables.less file instead.