我对这个问题的首选方法是基于make-grid-columns mixin，利用现有的Bootstrap变量创建一个SASS mixin。

// Custom Grid Columns
// 
// $name - determines the class names: eg. ".col-5ths, .col-sm-5ths ..."
// $size - determines the width (2.4 is one fifth of 12, the default number of columns)
@mixin custom-grid-columns($name, $size, $grid-columns: $grid-columns, $breakpoints: $grid-breakpoints) {
    $columns: round($grid-columns / $size);

    %custom-grid-column {
        @include make-col-ready();
    }

    @each $breakpoint in map-keys($breakpoints) {
        $infix: breakpoint-infix($breakpoint, $breakpoints);

        .col#{$infix}-#{$name} {
            @extend %custom-grid-column;
        }

        @include media-breakpoint-up($breakpoint, $breakpoints) {
            // Create column
            .col#{$infix}-#{$name} {
                @include make-col($size);
            }

            // Create offset
            @if not ($infix=="") {
                .offset#{$infix}-#{$name} {
                    @include make-col-offset($size);
                }
            }
        }
    }
}

然后可以调用mixin来生成自定义列类和偏移量类。

@include custom-grid-columns('5ths', 2.4);

我已经为任意数量的列创建了基于bootstrap定义的SASS mixin定义(个人而言，除了12列，我使用8、10和24列):

// Extended bootstrap grid system
//
// Framework grid generation
//
// Based on Bootstrap 'bootstrap/_grid-framework.scss'. Generates classes in form of `.col-(size)-x-num` of width x/num.

@mixin make-extended-grid-columns($num-columns, $i: 1, $list: ".col-xs-#{$i}-#{$num-columns}, .col-sm-#{$i}-#{$num-columns}, .col-md-#{$i}-#{$num-columns}, .col-lg-#{$i}-#{$num-columns}") {
    @for $i from (1 + 1) through $num-columns {
        $list: "#{$list}, .col-xs-#{$i}-#{$num-columns}, .col-sm-#{$i}-#{$num-columns}, .col-md-#{$i}-#{$num-columns}, .col-lg-#{$i}-#{$num-columns}";
    }
    #{$list} {
        position: relative;
        min-height: 1px;
        padding-left:  ($grid-gutter-width / 2);
        padding-right: ($grid-gutter-width / 2);
    }
}


@mixin float-extended-grid-columns($class, $num-columns, $i: 1, $list: ".col-#{$class}-#{$i}-#{$num-columns}") {
    @for $i from (1 + 1) through $num-columns {
        $list: "#{$list}, .col-#{$class}-#{$i}-#{$num-columns}";
    }
    #{$list} {
        float: left;
    }
}


@mixin calc-extended-grid-column($index, $num-columns, $class, $type) {
    @if ($type == width) and ($index > 0) {
        .col-#{$class}-#{$index}-#{$num-columns} {
            width: percentage(($index / $num-columns));
        }
    }
    @if ($type == push) and ($index > 0) {
        .col-#{$class}-push-#{$index}-#{$num-columns} {
            left: percentage(($index / $num-columns));
        }
    }
    @if ($type == pull) and ($index > 0) {
        .col-#{$class}-pull-#{$index}-#{$num-columns} {
            right: percentage(($index / $num-columns));
        }
    }
    @if ($type == offset) and ($index > 0) {
        .col-#{$class}-offset-#{$index}-#{$num-columns} {
            margin-left: percentage(($index / $num-columns));
        }
    }
}

@mixin loop-extended-grid-columns($num-columns, $class, $type) {
    @for $i from 1 through $num-columns - 1 {
        @include calc-extended-grid-column($i, $num-columns, $class, $type);
    }
}

@mixin make-extended-grid($class, $num-columns) {
    @include float-extended-grid-columns($class, $num-columns);
    @include loop-extended-grid-columns($num-columns, $class, width);
    @include loop-extended-grid-columns($num-columns, $class, pull);
    @include loop-extended-grid-columns($num-columns, $class, push);
    @include loop-extended-grid-columns($num-columns, $class, offset);
}

你可以简单地创建类:

$possible-number-extended-grid-columns: 8, 10, 24;

@each $num-columns in $possible-number-extended-grid-columns {

  // Columns

  @include make-extended-grid-columns($num-columns);

  // Extra small grid

  @include make-extended-grid(xs, $num-columns);

  // Small grid

  @media (min-width: $screen-sm-min) {
    @include make-extended-grid(sm, $num-columns);
  }

  // Medium grid

  @media (min-width: $screen-md-min) {
    @include make-extended-grid(md, $num-columns);
  }

  // Large grid

  @media (min-width: $screen-lg-min) {
    @include make-extended-grid(lg, $num-columns);
  }

}

我希望有人会觉得它有用

在bootstrap v4.3.1中，它是一个12 / 5 = 2.4列宽的列。我们称它为col-2dot4(以及col-sm-2dot4, col-md-2dot4，…)

每一列应该有20%的可用空间。

SCSS代码如下所示:

@mixin make-5-grid-column($columns: $grid-columns, $gutter: $grid-gutter-width, $breakpoints: $grid-breakpoints) {

  // Common properties for all breakpoints
  %grid-column {
    position: relative;
    width: 100%;
    padding-right: $gutter / 2;
    padding-left: $gutter / 2;
  }

  @each $breakpoint in map-keys($breakpoints) {
    $infix: breakpoint-infix($breakpoint, $breakpoints);

    .col#{$infix}-2dot4 {
      @extend %grid-column;
    }

    .col#{$infix},
    .col#{$infix}-auto {
      @extend %grid-column;
    }

    @include media-breakpoint-up($breakpoint, $breakpoints) {

      // Provide basic `.col-{bp}` classes for equal-width flexbox columns
      .col#{$infix} {
        flex-basis: 0;
        flex-grow: 1;
        max-width: 100%;
      }

      .col#{$infix}-auto {
        flex: 0 0 auto;
        width: auto;
        max-width: 100%; // Reset earlier grid tiers
      }


      .col#{$infix}-2dot4 {
        @include make-col(1, 5);
      }
    }
  }
}

@if $enable-grid-classes {
  @include make-5-grid-column();
}

我对Mafnah的答案进行了投票，但再看一遍，如果你保持默认的边际，我建议下面的答案更好。

<div class="equal row-fluid">
    <div class="span2"></div>
    <div class="span2"></div>
    <div class="span2"></div>
    <div class="span2"></div>
    <div class="span2"></div>
</div>

.equal .span2 {
    width: 17.9%;
}

下面是@machineaddict和@Mafnah回答的组合，为Bootstrap 3重写(到目前为止对我来说很好):

@media (min-width: 768px){
    .fivecolumns .col-md-2, .fivecolumns .col-sm-2, .fivecolumns .col-lg-2  {
        width: 20%;
        *width: 20%;
    }
}
@media (min-width: 1200px) {
    .fivecolumns .col-md-2, .fivecolumns .col-sm-2, .fivecolumns .col-lg-2 {
        width: 20%;
        *width: 20%;
    }
}
@media (min-width: 768px) and (max-width: 979px) {
    .fivecolumns .col-md-2, .fivecolumns .col-sm-2, .fivecolumns .col-lg-2 {
        width: 20%;
        *width: 20%;
    }
}

在bootstrap 3中，我认为我们可以这样做，删除左右边距:

<div class="row this_row">
    <div class="col-md-2 col-md-offset-1"></div>
    <div class="col-md-2"></div>
    <div class="col-md-2"></div>
    <div class="col-md-2"></div>
    <div class="col-md-2"></div>
</div>

和CSS

.this_row {
    margin: 0 -5%;
}