Differences Between Bootstrap 3 and Bootstrap 4

Bootstrap 4 brought some big changes, including new scrapping, components others. Here’s the difference between Bootstrap 3 & 4.


Component Bootstrap 3

Bootstrap 4

Source CSS Files LESS SCSS
Primary CSS Unit px rem
Media Queries Unit px px
Global Font Size 14px 16px
Default Fonts Helvetica Neue, Helvetica, Arial, sans-serif Uses a “native font stack” (user’s system fonts), with a fallback to Helvetica Neue, Arial, and sans-serif
Grid Tiers 4 tier grid system (xs, sm, md, lg) 5 tier grid system (xs, sm, md, lg, xl).

Bootstrap 4 has removed the xs from the lowest break point. Therefore, col-* covers all devices (no need to specify the size in this case).

Offsetting Columns Uses col-*-offset-* classes to offset columns. For example, col-md-offset-4. Uses offset-*-* classes to offset columns. For example, offset-md-4.
Dark/inverse Tables Not supported. Added dark/inverse tables with the .table-dark class.

Note: Prior to the Beta 2 release, these required the .table-inverse class. This class has been replaced with .table-darkin Beta 2.

Table Head Styles Not supported. Added table head styles with the .thead-light and .thead-dark classes.

Note: Prior to the Beta 2 release, these required the .table-default class and the .table-dark class. These classes have been replaced with .table-light and .table-dark in Beta 2.

Condensed Tables .table-condensed .table-sm
Contextual Classes Bootstrap 3 doesn’t use the .table- prefix for its contextual classes.

For example, Bootstrap 3 uses .activewhereas Bootstrap 4 uses .table-active. Other than that, both versions use the same 5 contextual keywords (active, success, info, warning, danger).

Added the .table- prefix for its contextual classes.
Responsive Tables The .table-responsive class must be added to a parent div element. The .table-responsive class must be added to a parent div element.

Can add .table-responsive to the actual table element.

Beta 2 has also introduced the .table-responsive-* classes that can be used to specify a particular breakpoint. These are .table-responsive-sm, .table-responsive-md, .table-responsive-lg, and .table-responsive-xl.

Reflow Tables Not supported. Added reflow tables with the .table-reflow class.

Reflow tables have now been dropped.

Horizontal Forms Horizontal forms require the .form-horizontal class.

Forms don’t require .row when using grids (although this class is still a requirement on Bootstrap 3 grids in general).

Bootstrap 4 dropped the .form-horizontal class — it is no longer needed to display horizontal forms.

Forms require either the .row class when using grids, or the .form-row class (introduced in Bootstrap 4), which makes the form more compact.

Use .control-label when using grids for form layout. Bootstrap 4 uses .col-form-label * when using grids for form layout.

* Note that Bootstrap 4 initially used .form-control-label but subesquently changed this to .col-form-label.

Checkboxes and Radio Buttons Uses .radio, .radio-inline, .checkbox, or .checkbox-inline to display checkboxes and radio buttons. Uses .form-check, .form-check-label, .form-check-input, and .form-check-inline.
Form Control Size Use .input-lg and .input-sm to increase or decrease the size of an input control. Use .form-control-lg and .form-control-sm to increase or decrease the size of an input control.
Form Label Size No specific classes for adjusting form label size. Bootstrap 4 introduced .col-form-label-sm and .col-form-label-lg to increase or decrease the size of a label to match the size of the relevant form control.
Help Text Use the .help-block class to display help text. Bootstrap 4 uses the .form-text class to display help text.
Validation and Feedback Icons Includes validation styles for error, warning, and success states on form controls (for example, .has-warning). To present icons on the input fields using Bootstrap 3, use glyphicons. Validation styles are not available for Bootstrap 4 forms. Use custom Bootstrap form validation messages instead.
Legends No classes for styling the form legends. Provides the option of using .col-form-label on legend elements to style it more like a label.
Static text Uses .form-control-static to render static text instead of a control. In Bootstrap 4, .form-control-static has been renamed to .form-control-plaintext.
Custom Forms Not supported. Bootstrap 4 introduced custom forms — completely custom form elements that replace the browser defaults.
Styles Includes the .btn-default and .btn-infoclasses.

The .btn-secondary class isn’t available in Bootstrap 3.

Introduced the .btn-secondary, .btn-light, and .btn-dark classes.

Dropped the .btn-default class.

Note that the .btn-info class was initially dropped in Bootstrap 4 but then reappeared again.

Outline Buttons Not supported. Introduced the .btn-outline-* classes for styling buttons with an outline color.

Introduced the .btn-*-outline classes for styling buttons with an outline color.

(The .btn-*-outline classes became .btn-outline-* in Alpha 3).

Button Sizes The .btn-xs class is available. Dropped the .btn-xs class (only .btn-smand .btn-lg are available now).
Input groups
Classes Bootstrap 3 uses the .input-group-addonand .input-group-btn classes. Bootstrap 4 dropped .input-group-addonand .input-group-btn for two new classes: .input-group-prepend and .input-group-append.

Bootstrap 4 also introduced .input-group-text for text within an input group.

Responsive Images Use .img-responsive class. Use .img-fluid class.
Image Alignment Use .pull-right, .pull-left, and .center-block helper classes. Uses .m-x-auto instead of .center-blockto align block-level images.

Can also use the various .pull-*-rightand .pull-*-left responsive helper classes, as well as the .text-*-left, .text-*-center, and .text-*-righthelper classes on the image’s parent.

Can use the various .pull-*-none classes to disable floating.

Media Objects
Classes Includes many different classes for media objects, including .media, .media-body.media-object, .media-heading, .media-right, .media-left, and .media-list and .media-body. Uses just .media class. Margins can be applied using spacer utilities. Media objects are flexbox enabled in Bootstrap 4, so the various flexbox classes can also be applied (such as reordering, etc).
Structure Apply dropdowns to lists (i.e. using uland li). Dropdowns can be built with ul or divs.

Apply the .dropdown-item to a a or button element and wrap them all in a div (or ul) with a .dropdown-menuclass applied.

Menu Headers Apply .dropdown-header to the li tag. Apply .dropdown-header to h1 – h2tags (as Bootstrap no longer uses litags to build dropdowns).
Dividers Apply the .divider class to the li element (because it used lists to build dropdowns). Apply the .dropdown-divider to the div element.
Disabled Menu Items Apply the .disabled class to the li element. Apply the .disabled class to the a element.
Button Groups
Justified? Supports justified button groups (via the .btn-group-justified class). Not supported.
Extra Small? Supports extra small button groups (via the .btn-group-xs class). Not supported (dropped the .btn-group-xs class).
Inline Navs There is no .nav-inline class. Can use the .nav-inline class to explicitly specify navs to be displayed inline.
Colors Limited (preset) color options. Supports inverse navbars but not the other classes. New (preset) color options. Introduced the .navbar-light and the .navbar-darkclasses, and allows the .bg-* classes to be used on navbars.
Navbar Alignment Use .navbar-right, .navbar-left to align components within the navbar. Use the various .pull-*-right and .pull-*-left responsive helper classes.

Can also use the various .pull-*-noneclasses to disable floating.

Can either use spacing utilities such as .mr-auto, or any of the flexbox alignment utilities.

Navbar Forms Add the .navbar-form class to forms within navbars. Bootstrap 4 dropped the .navbar-formclass. It’s no longer necessary.
Fixed Navbars Uses .navbar-fixed-top and .navbar-fixed-bottom to fix navbars to the top or bottom. Uses .fixed-top and .fixed-bottom.
Default Pagination Only requires .pagination to be added (to the ul element that represents the list of pages). Must also add .page-item to each li element and .page-link to each a element.
Pagers Uses .previous and .next for aligning pagers. Pagers have been dropped in Bootstrap 4 (Alpha 3).

Uses .pager-prev and .pager-next for aligning pagers.

Pill Labels The .label-pill class is not available. However, Bootstrap 3 does have badges (which achieves a similar visual effect). Labels have been replaced by badges in Bootstrap 4.

Badges can use the .badge-pill for rounded corners.

Supported? No.

“Tags” are called “Labels” in Bootstrap 3 (i.e. they use the .label class).


The .tag class was introduced in Bootstrap 4 (Alpha 3) to replace the .labelclass.

This was done to disambiguate from the label element.

Tags have now been renamed to “badges”. These replace labels from Bootstrap 3.

Full-Width The .jumbotron-fluid class is not required on full-width jumbotrons. Introduced the .jumbotron-fluid class for full-width jumbotrons.
Progress Bars
Uses progress? Doesn’t use the progress for progress bars. Instead, applies progress bar classes to nested div elements. Uses the HTML5 progress element when working with progress bars.

Using the progress element was abandoned in Alpha 6. Bootstrap 4 now uses the div element again.

Supported? Supported. Not supported.
Blockquotes Bootstrap styles are applied to the blockquote element by default. Introduced the .blockquote class for styling the blockquote element (i.e. styling this element is now opt-in).
Blockquote Alignment Use .blockquote-reverse to align a blockquote to the right. Use the text utilities to align blockquotes (.text-center and .text-right).
Page Headers The .page-header class is supported. The .page-header class is not supported.
Description Lists The .dl-horizontal class was used to declare a horizontal list. Horizontal lists are now declared with the .row class on the dl tag, then any of the grid system’s predefined classes to the dt and dd tags.
Non-Responsive Usage
Supported? Supported. You can specify a layout to be non-responsive. Not supported.
List Groups
Linked List Items / Button List Items Apply .list-group-item to the a element. Apply .list-group-item-action to the a element.
Show content Uses .in to have content expanded upon page load. Uses .show to have content expanded upon page load.
Supported? Not supported. Introduced in Bootstrap 4. Cards replace functionality that was previously provided by panelswells, and thumbnails.
Supported? Supported. Not supported. Use cards instead.
Supported? Supported. Not supported. Use cards instead.
Supported? Supported. Not supported. Use cards instead.
Classes Uses the .breadcrumb class against the ul tag. Also requires .breadcrumb-item to be applied against all li elements that make up the breadcrumb.

Breadcrumbs can also be used outside of lists. For example, the .breadcrumb-itemcould be applied to a bunch of a elements that are wrapped in a .breadcrumb element.

Carousel Item Use .item class. Use .carousel-item class.
Supported? Yes. No.